From 0ac4e297adf95cff78de361fc4867fd412ec3b60 Mon Sep 17 00:00:00 2001
From: Fathy Boundjadj <fathy.boundjadj@gmail.com>
Date: Thu, 14 Jun 2018 10:12:48 +0200
Subject: [PATCH] Scope hoisting for ES6 and CommonJS modules (#1135)

---
 package.json                                  |   3 +-
 src/Bundler.js                                |  33 +-
 src/FSCache.js                                |   2 +-
 src/Parser.js                                 |   4 +-
 src/Pipeline.js                               |  15 +-
 src/SourceMap.js                              |  79 +-
 src/assets/CSSAsset.js                        |   2 +-
 src/assets/GLSLAsset.js                       |   4 +-
 src/assets/GlobAsset.js                       |   9 +-
 src/assets/GraphqlAsset.js                    |   4 +-
 src/assets/JSAsset.js                         |  36 +-
 src/assets/JSONAsset.js                       |   6 +-
 src/assets/RawAsset.js                        |   9 +-
 src/assets/TOMLAsset.js                       |   7 +-
 src/assets/VueAsset.js                        |  33 +-
 src/assets/YAMLAsset.js                       |   7 +-
 src/builtins/.eslintrc.json                   |   5 +-
 src/builtins/bundle-loader.js                 |  16 +-
 src/builtins/helpers.js                       |  30 +
 src/builtins/prelude.js                       |   5 +
 src/builtins/prelude2.js                      |  45 ++
 src/cli.js                                    |   5 +
 src/packagers/JSConcatPackager.js             | 526 ++++++++++++
 src/packagers/JSPackager.js                   |   5 +-
 src/packagers/SourceMapPackager.js            |   1 +
 src/packagers/index.js                        |   5 +-
 src/scope-hoisting/concat.js                  | 394 +++++++++
 src/scope-hoisting/hoist.js                   | 570 +++++++++++++
 src/scope-hoisting/mangler.js                 |  69 ++
 src/scope-hoisting/renamer.js                 |  33 +
 src/scope-hoisting/shake.js                   | 126 +++
 src/transforms/terser.js                      |   2 +-
 src/visitors/globals.js                       |   3 +-
 src/worker.js                                 |   4 +-
 test/fs.js                                    |   6 +-
 test/integration/circular/about.js            |   4 +
 test/integration/circular/index.js            |   4 +
 .../commonjs/default-import/a.js              |   3 +
 .../commonjs/default-import/b.js              |   1 +
 .../commonjs/define-exports/a.js              |   7 +
 .../commonjs/eliminate-exports/a.js           |   4 +
 .../commonjs/eliminate-exports/b.js           |   6 +
 .../scope-hoisting/commonjs/empty-module/a.js |   3 +
 .../scope-hoisting/commonjs/empty-module/b.js |   0
 .../commonjs/es6-commonjs-hybrid/a.js         |   3 +
 .../commonjs/es6-commonjs-hybrid/b.js         |   2 +
 .../scope-hoisting/commonjs/export-order/a.js |   3 +
 .../scope-hoisting/commonjs/export-order/b.js |   2 +
 .../commonjs/import-namespace/a.js            |   3 +
 .../commonjs/import-namespace/b.js            |   1 +
 .../commonjs/live-bindings/a.js               |   5 +
 .../commonjs/live-bindings/b.js               |   7 +
 .../commonjs/module-object/a.js               |   8 +
 .../commonjs/module-object/package.json       |   3 +
 .../scope-hoisting/commonjs/multi-assign/a.js |   2 +
 .../scope-hoisting/commonjs/named-import/a.js |   3 +
 .../scope-hoisting/commonjs/named-import/b.js |   1 +
 .../commonjs/object-pattern/a.js              |   2 +
 .../commonjs/object-pattern/b.js              |   2 +
 .../commonjs/object-pattern/package.json      |   4 +
 .../commonjs/re-export-var/a.js               |   3 +
 .../commonjs/re-export-var/b.js               |   3 +
 .../commonjs/re-export-var/c.js               |   7 +
 .../commonjs/require-circular/a.js            |   2 +
 .../commonjs/require-circular/b.js            |   1 +
 .../commonjs/require-conditional/a.js         |   7 +
 .../commonjs/require-conditional/b.js         |   2 +
 .../commonjs/require-conditional/c.js         |   1 +
 .../require-default-export-declaration/a.js   |   3 +
 .../require-default-export-declaration/b.js   |   3 +
 .../require-default-export-expression/a.js    |   3 +
 .../require-default-export-expression/b.js    |   1 +
 .../require-default-export-variable/a.js      |   3 +
 .../require-default-export-variable/b.js      |   2 +
 .../commonjs/require-execution-order/a.js     |   3 +
 .../commonjs/require-execution-order/b.js     |   2 +
 .../commonjs/require-execution-order/c.js     |   1 +
 .../require-in-function-import-hoist/a.js     |   8 +
 .../require-in-function-import-hoist/b.js     |   2 +
 .../require-in-function-import-hoist/c.js     |   1 +
 .../commonjs/require-in-function-import/a.js  |   8 +
 .../commonjs/require-in-function-import/b.js  |   2 +
 .../commonjs/require-in-function-import/c.js  |   1 +
 .../require-in-function-reexport/a.js         |   8 +
 .../require-in-function-reexport/b.js         |   2 +
 .../require-in-function-reexport/c.js         |   2 +
 .../commonjs/require-in-function/a.js         |   8 +
 .../commonjs/require-in-function/b.js         |   2 +
 .../require-named-export-declaration/a.js     |   3 +
 .../require-named-export-declaration/b.js     |   1 +
 .../require-named-export-variable/a.js        |   3 +
 .../require-named-export-variable/b.js        |   2 +
 .../commonjs/require-re-export-all/a.js       |   3 +
 .../commonjs/require-re-export-all/b.js       |   2 +
 .../commonjs/require-re-export-all/c.js       |   1 +
 .../commonjs/require-re-export-default/a.js   |   3 +
 .../commonjs/require-re-export-default/b.js   |   2 +
 .../commonjs/require-re-export-default/c.js   |   1 +
 .../require-re-export-exclude-default/a.js    |   1 +
 .../require-re-export-exclude-default/b.js    |   1 +
 .../require-re-export-exclude-default/c.js    |   2 +
 .../commonjs/require-re-export-multiple/a.js  |   3 +
 .../commonjs/require-re-export-multiple/b.js  |   2 +
 .../commonjs/require-re-export-multiple/c.js  |   2 +
 .../commonjs/require-re-export-multiple/d.js  |   1 +
 .../commonjs/require-re-export-named/a.js     |   3 +
 .../commonjs/require-re-export-named/b.js     |   2 +
 .../commonjs/require-re-export-named/c.js     |   1 +
 .../commonjs/require-re-export-namespace/a.js |   3 +
 .../commonjs/require-re-export-namespace/b.js |   4 +
 .../commonjs/require-re-export-namespace/c.js |   1 +
 .../commonjs/require-renamed-export/a.js      |   3 +
 .../commonjs/require-renamed-export/b.js      |   2 +
 .../commonjs/require-resolve/a.js             |   3 +
 .../commonjs/require-resolve/b.js             |   1 +
 .../scope-hoisting/commonjs/require/a.js      |   3 +
 .../scope-hoisting/commonjs/require/b.js      |   1 +
 .../commonjs/stream-module/a.js               |   1 +
 .../commonjs/this-reference-wrapped/a.js      |   3 +
 .../commonjs/this-reference-wrapped/b.js      |   2 +
 .../commonjs/this-reference/a.js              |   3 +
 .../commonjs/this-reference/b.js              |   1 +
 .../scope-hoisting/commonjs/tree-shaking/a.js |   1 +
 .../scope-hoisting/commonjs/tree-shaking/b.js |   2 +
 .../scope-hoisting/commonjs/wrap-eval/a.js    |   3 +
 .../scope-hoisting/commonjs/wrap-eval/b.js    |   2 +
 .../commonjs/wrap-module-computed/a.js        |   2 +
 .../scope-hoisting/commonjs/wrap-module/a.js  |   2 +
 .../scope-hoisting/commonjs/wrap-return/a.js  |   3 +
 .../scope-hoisting/commonjs/wrap-return/b.js  |   3 +
 .../es6/default-export-anonymous/a.js         |   3 +
 .../es6/default-export-anonymous/b.js         |   3 +
 .../es6/default-export-declaration/a.js       |   3 +
 .../es6/default-export-declaration/b.js       |   3 +
 .../es6/default-export-expression/a.js        |   3 +
 .../es6/default-export-expression/b.js        |   1 +
 .../es6/default-export-variable/a.js          |   3 +
 .../es6/default-export-variable/b.js          |   2 +
 .../es6/dynamic-default-interop/a.js          |   3 +
 .../es6/dynamic-default-interop/b.js          |   3 +
 .../es6/dynamic-default-interop/shared.js     |   1 +
 .../scope-hoisting/es6/dynamic-import/a.js    |   7 +
 .../scope-hoisting/es6/dynamic-import/b.js    |   4 +
 .../scope-hoisting/es6/dynamic-import/c.js    |   3 +
 .../scope-hoisting/es6/empty-module/a.js      |   3 +
 .../scope-hoisting/es6/empty-module/b.js      |   0
 .../es6/export-binding-identifiers/a.js       |   3 +
 .../es6/export-binding-identifiers/b.js       |   3 +
 .../es6/import-commonjs-default/a.js          |   4 +
 .../es6/import-commonjs-default/exports.js    |   1 +
 .../es6/import-commonjs-default/wrapped.js    |   3 +
 .../es6/import-namespace-commonjs/a.js        |   6 +
 .../es6/import-namespace-commonjs/b.js        |   3 +
 .../es6/import-namespace-commonjs/c.js        |   1 +
 .../scope-hoisting/es6/import-namespace/a.js  |   3 +
 .../scope-hoisting/es6/import-namespace/b.js  |   1 +
 .../scope-hoisting/es6/live-bindings/a.js     |   5 +
 .../scope-hoisting/es6/live-bindings/b.js     |   7 +
 .../scope-hoisting/es6/multi-export/a.js      |   3 +
 .../scope-hoisting/es6/multi-export/b.js      |   3 +
 .../es6/named-export-declaration/a.js         |   3 +
 .../es6/named-export-declaration/b.js         |   1 +
 .../es6/named-export-variable/a.js            |   3 +
 .../es6/named-export-variable/b.js            |   2 +
 .../es6/re-export-all-multiple/a.js           |   3 +
 .../es6/re-export-all-multiple/b.js           |   3 +
 .../es6/re-export-all-multiple/c.js           |   1 +
 .../es6/re-export-all-multiple/d.js           |   1 +
 .../scope-hoisting/es6/re-export-all/a.js     |   3 +
 .../scope-hoisting/es6/re-export-all/b.js     |   2 +
 .../scope-hoisting/es6/re-export-all/c.js     |   1 +
 .../scope-hoisting/es6/re-export-default/a.js |   3 +
 .../scope-hoisting/es6/re-export-default/b.js |   2 +
 .../scope-hoisting/es6/re-export-default/c.js |   1 +
 .../es6/re-export-exclude-default/a.js        |   3 +
 .../es6/re-export-exclude-default/b.js        |   1 +
 .../es6/re-export-exclude-default/c.js        |   2 +
 .../es6/re-export-multiple/a.js               |   3 +
 .../es6/re-export-multiple/b.js               |   2 +
 .../es6/re-export-multiple/c.js               |   2 +
 .../es6/re-export-multiple/d.js               |   1 +
 .../scope-hoisting/es6/re-export-named/a.js   |   3 +
 .../scope-hoisting/es6/re-export-named/b.js   |   2 +
 .../scope-hoisting/es6/re-export-named/c.js   |   1 +
 .../es6/re-export-namespace/a.js              |   3 +
 .../es6/re-export-namespace/b.js              |   2 +
 .../es6/re-export-namespace/c.js              |   1 +
 .../scope-hoisting/es6/re-export-var/a.js     |   3 +
 .../scope-hoisting/es6/re-export-var/b.js     |   3 +
 .../scope-hoisting/es6/re-export-var/c.js     |   7 +
 .../scope-hoisting/es6/renamed-export/a.js    |   3 +
 .../scope-hoisting/es6/renamed-export/b.js    |   2 +
 .../scope-hoisting/es6/renamed-import/a.js    |   3 +
 .../scope-hoisting/es6/renamed-import/b.js    |   1 +
 .../es6/side-effects-false/a.js               |   3 +
 .../node_modules/bar/bar.js                   |   5 +
 .../node_modules/bar/foo.js                   |   3 +
 .../node_modules/bar/index.js                 |   2 +
 .../node_modules/bar/package.json             |   4 +
 .../scope-hoisting/es6/side-effects/a.js      |   3 +
 .../es6/side-effects/node_modules/bar/bar.js  |   5 +
 .../es6/side-effects/node_modules/bar/foo.js  |   3 +
 .../side-effects/node_modules/bar/index.js    |   2 +
 .../node_modules/bar/package.json             |   3 +
 .../scope-hoisting/es6/tree-shaking/a.js      |   2 +
 .../scope-hoisting/es6/tree-shaking/b.js      |   2 +
 test/integration/sourcemap-reference/data.js  |   6 +
 .../integration/sourcemap-reference/data.json |   6 -
 test/integration/sourcemap-reference/index.js |   3 +-
 test/javascript.js                            |  59 +-
 test/scope-hoisting.js                        | 761 ++++++++++++++++++
 test/sourcemaps.js                            |   2 +-
 test/utils.js                                 |  13 +-
 test/watcher.js                               |   8 +-
 214 files changed, 3299 insertions(+), 129 deletions(-)
 create mode 100644 src/builtins/helpers.js
 create mode 100644 src/builtins/prelude2.js
 create mode 100644 src/packagers/JSConcatPackager.js
 create mode 100644 src/scope-hoisting/concat.js
 create mode 100644 src/scope-hoisting/hoist.js
 create mode 100644 src/scope-hoisting/mangler.js
 create mode 100644 src/scope-hoisting/renamer.js
 create mode 100644 src/scope-hoisting/shake.js
 create mode 100644 test/integration/scope-hoisting/commonjs/default-import/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/default-import/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/define-exports/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/eliminate-exports/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/eliminate-exports/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/empty-module/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/empty-module/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/es6-commonjs-hybrid/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/es6-commonjs-hybrid/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/export-order/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/export-order/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/import-namespace/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/import-namespace/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/live-bindings/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/live-bindings/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/module-object/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/module-object/package.json
 create mode 100644 test/integration/scope-hoisting/commonjs/multi-assign/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/named-import/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/named-import/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/object-pattern/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/object-pattern/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/object-pattern/package.json
 create mode 100644 test/integration/scope-hoisting/commonjs/re-export-var/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/re-export-var/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/re-export-var/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-circular/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-circular/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-conditional/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-conditional/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-conditional/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-default-export-declaration/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-default-export-declaration/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-default-export-expression/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-default-export-expression/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-default-export-variable/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-default-export-variable/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-execution-order/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-execution-order/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-execution-order/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-in-function-import/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-in-function-import/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-in-function-import/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-in-function-reexport/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-in-function-reexport/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-in-function-reexport/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-in-function/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-in-function/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-named-export-declaration/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-named-export-declaration/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-named-export-variable/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-named-export-variable/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-all/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-all/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-all/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-default/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-default/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-default/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-multiple/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-multiple/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-multiple/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-multiple/d.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-named/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-named/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-named/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-namespace/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-namespace/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-re-export-namespace/c.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-renamed-export/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-renamed-export/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-resolve/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require-resolve/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/require/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/stream-module/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/this-reference-wrapped/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/this-reference-wrapped/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/this-reference/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/this-reference/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/tree-shaking/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/tree-shaking/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/wrap-eval/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/wrap-eval/b.js
 create mode 100644 test/integration/scope-hoisting/commonjs/wrap-module-computed/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/wrap-module/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/wrap-return/a.js
 create mode 100644 test/integration/scope-hoisting/commonjs/wrap-return/b.js
 create mode 100644 test/integration/scope-hoisting/es6/default-export-anonymous/a.js
 create mode 100644 test/integration/scope-hoisting/es6/default-export-anonymous/b.js
 create mode 100644 test/integration/scope-hoisting/es6/default-export-declaration/a.js
 create mode 100644 test/integration/scope-hoisting/es6/default-export-declaration/b.js
 create mode 100644 test/integration/scope-hoisting/es6/default-export-expression/a.js
 create mode 100644 test/integration/scope-hoisting/es6/default-export-expression/b.js
 create mode 100644 test/integration/scope-hoisting/es6/default-export-variable/a.js
 create mode 100644 test/integration/scope-hoisting/es6/default-export-variable/b.js
 create mode 100644 test/integration/scope-hoisting/es6/dynamic-default-interop/a.js
 create mode 100644 test/integration/scope-hoisting/es6/dynamic-default-interop/b.js
 create mode 100644 test/integration/scope-hoisting/es6/dynamic-default-interop/shared.js
 create mode 100644 test/integration/scope-hoisting/es6/dynamic-import/a.js
 create mode 100644 test/integration/scope-hoisting/es6/dynamic-import/b.js
 create mode 100644 test/integration/scope-hoisting/es6/dynamic-import/c.js
 create mode 100644 test/integration/scope-hoisting/es6/empty-module/a.js
 create mode 100644 test/integration/scope-hoisting/es6/empty-module/b.js
 create mode 100644 test/integration/scope-hoisting/es6/export-binding-identifiers/a.js
 create mode 100644 test/integration/scope-hoisting/es6/export-binding-identifiers/b.js
 create mode 100644 test/integration/scope-hoisting/es6/import-commonjs-default/a.js
 create mode 100644 test/integration/scope-hoisting/es6/import-commonjs-default/exports.js
 create mode 100644 test/integration/scope-hoisting/es6/import-commonjs-default/wrapped.js
 create mode 100644 test/integration/scope-hoisting/es6/import-namespace-commonjs/a.js
 create mode 100644 test/integration/scope-hoisting/es6/import-namespace-commonjs/b.js
 create mode 100644 test/integration/scope-hoisting/es6/import-namespace-commonjs/c.js
 create mode 100644 test/integration/scope-hoisting/es6/import-namespace/a.js
 create mode 100644 test/integration/scope-hoisting/es6/import-namespace/b.js
 create mode 100644 test/integration/scope-hoisting/es6/live-bindings/a.js
 create mode 100644 test/integration/scope-hoisting/es6/live-bindings/b.js
 create mode 100644 test/integration/scope-hoisting/es6/multi-export/a.js
 create mode 100644 test/integration/scope-hoisting/es6/multi-export/b.js
 create mode 100644 test/integration/scope-hoisting/es6/named-export-declaration/a.js
 create mode 100644 test/integration/scope-hoisting/es6/named-export-declaration/b.js
 create mode 100644 test/integration/scope-hoisting/es6/named-export-variable/a.js
 create mode 100644 test/integration/scope-hoisting/es6/named-export-variable/b.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-all-multiple/a.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-all-multiple/b.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-all-multiple/c.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-all-multiple/d.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-all/a.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-all/b.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-all/c.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-default/a.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-default/b.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-default/c.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-exclude-default/a.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-exclude-default/b.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-exclude-default/c.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-multiple/a.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-multiple/b.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-multiple/c.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-multiple/d.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-named/a.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-named/b.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-named/c.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-namespace/a.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-namespace/b.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-namespace/c.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-var/a.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-var/b.js
 create mode 100644 test/integration/scope-hoisting/es6/re-export-var/c.js
 create mode 100644 test/integration/scope-hoisting/es6/renamed-export/a.js
 create mode 100644 test/integration/scope-hoisting/es6/renamed-export/b.js
 create mode 100644 test/integration/scope-hoisting/es6/renamed-import/a.js
 create mode 100644 test/integration/scope-hoisting/es6/renamed-import/b.js
 create mode 100644 test/integration/scope-hoisting/es6/side-effects-false/a.js
 create mode 100644 test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/bar.js
 create mode 100644 test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/foo.js
 create mode 100644 test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/index.js
 create mode 100644 test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/package.json
 create mode 100644 test/integration/scope-hoisting/es6/side-effects/a.js
 create mode 100644 test/integration/scope-hoisting/es6/side-effects/node_modules/bar/bar.js
 create mode 100644 test/integration/scope-hoisting/es6/side-effects/node_modules/bar/foo.js
 create mode 100644 test/integration/scope-hoisting/es6/side-effects/node_modules/bar/index.js
 create mode 100644 test/integration/scope-hoisting/es6/side-effects/node_modules/bar/package.json
 create mode 100644 test/integration/scope-hoisting/es6/tree-shaking/a.js
 create mode 100644 test/integration/scope-hoisting/es6/tree-shaking/b.js
 create mode 100644 test/integration/sourcemap-reference/data.js
 delete mode 100644 test/integration/sourcemap-reference/data.json
 create mode 100644 test/scope-hoisting.js

diff --git a/package.json b/package.json
index 7d90846c7bc..2fbd8ab6786 100644
--- a/package.json
+++ b/package.json
@@ -106,8 +106,7 @@
     "format": "prettier --write \"./{src,bin,test}/**/*.{js,json,md}\"",
     "build": "yarn minify && babel src -d lib && ncp src/builtins lib/builtins",
     "prepublish": "yarn build",
-    "minify":
-      "terser -c -m -o src/builtins/prelude.min.js src/builtins/prelude.js",
+    "minify": "terser -c -m -o src/builtins/prelude.min.js src/builtins/prelude.js && terser -c -m -o src/builtins/prelude2.min.js src/builtins/prelude2.js",
     "precommit": "npm run lint && lint-staged",
     "lint":
       "eslint . && prettier \"./{src,bin,test}/**/*.{js,json,md}\" --list-different",
diff --git a/src/Bundler.js b/src/Bundler.js
index 9c84793729f..5698f5efc52 100644
--- a/src/Bundler.js
+++ b/src/Bundler.js
@@ -35,7 +35,7 @@ class Bundler extends EventEmitter {
 
     this.resolver = new Resolver(this.options);
     this.parser = new Parser(this.options);
-    this.packagers = new PackagerRegistry();
+    this.packagers = new PackagerRegistry(this.options);
     this.cache = this.options.cache ? new FSCache(this.options) : null;
     this.delegate = options.delegate || {};
     this.bundleLoaders = {};
@@ -91,6 +91,14 @@ class Bundler extends EventEmitter {
     const watch =
       typeof options.watch === 'boolean' ? options.watch : !isProduction;
     const target = options.target || 'browser';
+    const hmr =
+      target === 'node'
+        ? false
+        : typeof options.hmr === 'boolean'
+          ? options.hmr
+          : watch;
+    const scopeHoist =
+      options.scopeHoist !== undefined ? options.scopeHoist : false;
     return {
       production: isProduction,
       outDir: Path.resolve(options.outDir || 'dist'),
@@ -104,19 +112,15 @@ class Bundler extends EventEmitter {
       minify:
         typeof options.minify === 'boolean' ? options.minify : isProduction,
       target: target,
-      hmr:
-        target === 'node'
-          ? false
-          : typeof options.hmr === 'boolean'
-            ? options.hmr
-            : watch,
+      hmr: hmr,
       https: options.https || false,
       logLevel: isNaN(options.logLevel) ? 3 : options.logLevel,
       entryFiles: this.entryFiles,
       hmrPort: options.hmrPort || 0,
       rootDir: getRootDir(this.entryFiles),
       sourceMaps:
-        typeof options.sourceMaps === 'boolean' ? options.sourceMaps : true,
+        (typeof options.sourceMaps === 'boolean' ? options.sourceMaps : true) &&
+        !scopeHoist,
       hmrHostname:
         options.hmrHostname ||
         (options.target === 'electron' ? 'localhost' : ''),
@@ -126,6 +130,7 @@ class Bundler extends EventEmitter {
         typeof options.autoinstall === 'boolean'
           ? options.autoinstall
           : !isProduction,
+      scopeHoist: scopeHoist,
       contentHash:
         typeof options.contentHash === 'boolean'
           ? options.contentHash
@@ -246,6 +251,8 @@ class Bundler extends EventEmitter {
         asset.invalidateBundle();
       }
 
+      logger.status(emoji.progress, `Producing bundles...`);
+
       // Create a root bundle to hold all of the entry assets, and add them to the tree.
       this.mainBundle = new Bundle();
       for (let asset of this.entryAssets) {
@@ -271,6 +278,8 @@ class Bundler extends EventEmitter {
         this.hmr.emitUpdate(changedAssets);
       }
 
+      logger.status(emoji.progress, `Packaging...`);
+
       // Package everything up
       this.bundleHashes = await this.mainBundle.package(
         this,
@@ -318,7 +327,7 @@ class Bundler extends EventEmitter {
     }
 
     await this.loadPlugins();
-    
+
     if (!this.options.env) {
       await loadEnv(Path.join(this.options.rootDir, 'index'));
       this.options.env = process.env;
@@ -508,14 +517,17 @@ class Bundler extends EventEmitter {
     let processed = this.cache && (await this.cache.read(asset.name));
     let cacheMiss = false;
     if (!processed || asset.shouldInvalidate(processed.cacheData)) {
-      processed = await this.farm.run(asset.name);
+      processed = await this.farm.run(asset.name, asset.id);
+      processed.id = asset.id;
       cacheMiss = true;
     }
 
     asset.endTime = Date.now();
     asset.buildTime = asset.endTime - asset.startTime;
+    asset.id = processed.id;
     asset.generated = processed.generated;
     asset.hash = processed.hash;
+    asset.cacheData = processed.cacheData;
 
     // Call the delegate to get implicit dependencies
     let dependencies = processed.dependencies;
@@ -535,6 +547,7 @@ class Bundler extends EventEmitter {
           // that changing it triggers a recompile of the parent.
           this.watch(dep.name, asset);
         } else {
+          dep.parent = asset.name;
           let assetDep = await this.resolveDep(asset, dep);
           if (assetDep) {
             await this.loadAsset(assetDep);
diff --git a/src/FSCache.js b/src/FSCache.js
index 38c842f0db4..fdfd98166e1 100644
--- a/src/FSCache.js
+++ b/src/FSCache.js
@@ -6,7 +6,7 @@ const pkg = require('../package.json');
 const logger = require('./Logger');
 
 // These keys can affect the output, so if they differ, the cache should not match
-const OPTION_KEYS = ['publicURL', 'minify', 'hmr', 'target'];
+const OPTION_KEYS = ['publicURL', 'minify', 'hmr', 'target', 'scopeHoist'];
 
 class FSCache {
   constructor(options) {
diff --git a/src/Parser.js b/src/Parser.js
index 22ac505ce8e..8c6fc23b50e 100644
--- a/src/Parser.js
+++ b/src/Parser.js
@@ -61,8 +61,8 @@ class Parser {
     this.extensions[ext.toLowerCase()] = parser;
   }
 
-  findParser(filename) {
-    if (/[*+{}]/.test(filename) && glob.hasMagic(filename)) {
+  findParser(filename, fromPipeline) {
+    if (!fromPipeline && /[*+{}]/.test(filename) && glob.hasMagic(filename)) {
       return GlobAsset;
     }
 
diff --git a/src/Pipeline.js b/src/Pipeline.js
index 40f588ced8a..6483bd9ed1a 100644
--- a/src/Pipeline.js
+++ b/src/Pipeline.js
@@ -11,13 +11,15 @@ class Pipeline {
     this.parser = new Parser(options);
   }
 
-  async process(path, isWarmUp) {
+  async process(path, id, isWarmUp) {
     let options = this.options;
     if (isWarmUp) {
       options = Object.assign({isWarmUp}, options);
     }
 
     let asset = this.parser.getAsset(path, options);
+    asset.id = id;
+
     let generated = await this.processAsset(asset);
     let generatedMap = {};
     for (let rendition of generated) {
@@ -52,17 +54,19 @@ class Pipeline {
       // Find an asset type for the rendition type.
       // If the asset is not already an instance of this asset type, process it.
       let AssetType = this.parser.findParser(
-        asset.name.slice(0, -inputType.length) + type
+        asset.name.slice(0, -inputType.length) + type,
+        true
       );
       if (!(asset instanceof AssetType)) {
-        let opts = Object.assign({rendition}, asset.options);
+        let opts = Object.assign({}, asset.options, {rendition});
         let subAsset = new AssetType(asset.name, opts);
+        subAsset.id = asset.id;
         subAsset.contents = value;
         subAsset.dependencies = asset.dependencies;
+        subAsset.cacheData = Object.assign(asset.cacheData, subAsset.cacheData);
 
         let processed = await this.processAsset(subAsset);
         generated = generated.concat(processed);
-        Object.assign(asset.cacheData, subAsset.cacheData);
         asset.hash = md5(asset.hash + subAsset.hash);
       } else {
         generated.push(rendition);
@@ -98,7 +102,8 @@ class Pipeline {
       yield {
         type,
         value: asset.generated[type],
-        final: true
+        // for scope hoisting, we need to post process all JS
+        final: !(type === 'js' && this.options.scopeHoist)
       };
     }
   }
diff --git a/src/SourceMap.js b/src/SourceMap.js
index eee70281efe..6b97a2fa1f7 100644
--- a/src/SourceMap.js
+++ b/src/SourceMap.js
@@ -149,8 +149,8 @@ class SourceMap {
         column: mapping.original.column
       });
 
-      if (!originalMapping.line) {
-        return false;
+      if (!originalMapping || !originalMapping.line) {
+        return;
       }
 
       this.addMapping({
@@ -182,7 +182,60 @@ class SourceMap {
     return this;
   }
 
-  findClosest(line, column, key = 'original') {
+  findClosestGenerated(line, column) {
+    if (line < 1) {
+      throw new Error('Line numbers must be >= 1');
+    }
+
+    if (column < 0) {
+      throw new Error('Column numbers must be >= 0');
+    }
+
+    if (this.mappings.length < 1) {
+      return undefined;
+    }
+
+    let startIndex = 0;
+    let stopIndex = this.mappings.length - 1;
+    let middleIndex = (stopIndex + startIndex) >>> 1;
+
+    while (
+      startIndex < stopIndex &&
+      this.mappings[middleIndex].generated.line !== line
+    ) {
+      let mid = this.mappings[middleIndex].generated.line;
+      if (line < mid) {
+        stopIndex = middleIndex - 1;
+      } else if (line > mid) {
+        startIndex = middleIndex + 1;
+      }
+      middleIndex = (stopIndex + startIndex) >>> 1;
+    }
+
+    let mapping = this.mappings[middleIndex];
+    if (!mapping || mapping.generated.line !== line) {
+      return this.mappings.length - 1;
+    }
+
+    while (
+      middleIndex >= 1 &&
+      this.mappings[middleIndex - 1].generated.line === line
+    ) {
+      middleIndex--;
+    }
+
+    while (
+      middleIndex < this.mappings.length - 1 &&
+      this.mappings[middleIndex + 1].generated.line === line &&
+      column > this.mappings[middleIndex].generated.column
+    ) {
+      middleIndex++;
+    }
+
+    return middleIndex;
+  }
+
+  findClosest(line, column, key) {
     if (line < 1) {
       throw new Error('Line numbers must be >= 1');
     }
@@ -211,7 +264,7 @@ class SourceMap {
       middleIndex = Math.floor((stopIndex + startIndex) / 2);
     }
 
-    let mapping = this.mappings[middleIndex];
+    var mapping = this.mappings[middleIndex];
     if (!mapping || mapping[key].line !== line) {
       return this.mappings.length - 1;
     }
@@ -235,16 +288,20 @@ class SourceMap {
   }
 
   originalPositionFor(generatedPosition) {
-    let index = this.findClosest(
+    let index = this.findClosestGenerated(
       generatedPosition.line,
-      generatedPosition.column,
-      'generated'
+      generatedPosition.column
     );
+    let mapping = this.mappings[index];
+    if (!mapping) {
+      return null;
+    }
+
     return {
-      source: this.mappings[index].source,
-      name: this.mappings[index].name,
-      line: this.mappings[index].original.line,
-      column: this.mappings[index].original.column
+      source: mapping.source,
+      name: mapping.name,
+      line: mapping.original.line,
+      column: mapping.original.column
     };
   }
 
diff --git a/src/assets/CSSAsset.js b/src/assets/CSSAsset.js
index c79bb355364..4cf066ac1f0 100644
--- a/src/assets/CSSAsset.js
+++ b/src/assets/CSSAsset.js
@@ -125,7 +125,7 @@ class CSSAsset extends Asset {
       {
         type: 'js',
         value: js,
-        final: true
+        hasDependencies: false
       }
     ];
   }
diff --git a/src/assets/GLSLAsset.js b/src/assets/GLSLAsset.js
index 50019952cce..fb67e73242c 100644
--- a/src/assets/GLSLAsset.js
+++ b/src/assets/GLSLAsset.js
@@ -53,9 +53,7 @@ class GLSLAsset extends Asset {
     const glslifyBundle = await localRequire('glslify-bundle', this.name);
     let glsl = glslifyBundle(this.ast);
 
-    return {
-      js: `module.exports=${JSON.stringify(glsl)};`
-    };
+    return `module.exports=${JSON.stringify(glsl)};`;
   }
 }
 
diff --git a/src/assets/GlobAsset.js b/src/assets/GlobAsset.js
index bb567d00e1d..63f151f5bde 100644
--- a/src/assets/GlobAsset.js
+++ b/src/assets/GlobAsset.js
@@ -38,9 +38,12 @@ class GlobAsset extends Asset {
   }
 
   generate() {
-    return {
-      js: 'module.exports = ' + generate(this.contents) + ';'
-    };
+    return [
+      {
+        type: 'js',
+        value: 'module.exports = ' + generate(this.contents) + ';'
+      }
+    ];
   }
 }
 
diff --git a/src/assets/GraphqlAsset.js b/src/assets/GraphqlAsset.js
index af15efe6edf..62e7a3563d9 100644
--- a/src/assets/GraphqlAsset.js
+++ b/src/assets/GraphqlAsset.js
@@ -13,9 +13,7 @@ class GraphqlAsset extends Asset {
   }
 
   generate() {
-    return {
-      js: `module.exports=${JSON.stringify(this.ast, false, 2)};`
-    };
+    return `module.exports=${JSON.stringify(this.ast, false, 2)};`;
   }
 }
 
diff --git a/src/assets/JSAsset.js b/src/assets/JSAsset.js
index cfdc370fe0e..57301b8956d 100644
--- a/src/assets/JSAsset.js
+++ b/src/assets/JSAsset.js
@@ -12,6 +12,7 @@ const babel = require('../transforms/babel');
 const generate = require('babel-generator').default;
 const terser = require('../transforms/terser');
 const SourceMap = require('../SourceMap');
+const hoist = require('../scope-hoisting/hoist');
 
 const IMPORT_RE = /\b(?:import\b|export\b|require\s*\()/;
 const ENV_RE = /\b(?:process\.env)\b/;
@@ -29,7 +30,8 @@ class JSAsset extends Asset {
     this.isES6Module = false;
     this.outputCode = null;
     this.cacheData.env = {};
-    this.sourceMap = options.rendition ? options.rendition.sourceMap : null;
+    this.rendition = options.rendition;
+    this.sourceMap = this.rendition ? this.rendition.sourceMap : null;
   }
 
   shouldInvalidate(cacheData) {
@@ -82,6 +84,15 @@ class JSAsset extends Asset {
   }
 
   traverse(visitor) {
+    // Create a babel File object if one hasn't been created yet.
+    // This is needed so that cached NodePath objects get a `hub` object on them.
+    // Plugins like babel-minify depend on this to get the original source code string.
+    if (!this.babelFile) {
+      this.babelFile = new BabelFile(this.babelConfig || {});
+      this.babelFile.addCode(this.contents);
+      this.babelFile.addAst(this.ast);
+    }
+
     return traverse(this.ast, visitor, null, this);
   }
 
@@ -123,8 +134,16 @@ class JSAsset extends Asset {
       }
     }
 
-    if (this.isES6Module) {
-      await babel(this);
+    if (this.options.scopeHoist) {
+      await this.parseIfNeeded();
+      await this.getPackage();
+
+      this.traverse(hoist);
+      this.isAstDirty = true;
+    } else {
+      if (this.isES6Module) {
+        await babel(this);
+      }
     }
 
     if (this.options.minify) {
@@ -133,6 +152,9 @@ class JSAsset extends Asset {
   }
 
   async generate() {
+    let enableSourceMaps =
+      this.options.sourceMaps &&
+      (!this.rendition || !!this.rendition.sourceMap);
     let code;
     if (this.isAstDirty) {
       let opts = {
@@ -142,7 +164,7 @@ class JSAsset extends Asset {
 
       let generated = generate(this.ast, opts, this.contents);
 
-      if (this.options.sourceMaps && generated.rawMappings) {
+      if (enableSourceMaps && generated.rawMappings) {
         let rawMap = new SourceMap(generated.rawMappings, {
           [this.relativeName]: this.contents
         });
@@ -161,10 +183,10 @@ class JSAsset extends Asset {
 
       code = generated.code;
     } else {
-      code = this.outputCode || this.contents;
+      code = this.outputCode != null ? this.outputCode : this.contents;
     }
 
-    if (this.options.sourceMaps && !this.sourceMap) {
+    if (enableSourceMaps && !this.sourceMap) {
       this.sourceMap = new SourceMap().generateEmptyMap(
         this.relativeName,
         this.contents
@@ -173,7 +195,7 @@ class JSAsset extends Asset {
 
     if (this.globals.size > 0) {
       code = Array.from(this.globals.values()).join('\n') + '\n' + code;
-      if (this.options.sourceMaps) {
+      if (enableSourceMaps) {
         if (!(this.sourceMap instanceof SourceMap)) {
           this.sourceMap = await new SourceMap().addMap(this.sourceMap);
         }
diff --git a/src/assets/JSONAsset.js b/src/assets/JSONAsset.js
index 2979b7e1d31..203223beb5b 100644
--- a/src/assets/JSONAsset.js
+++ b/src/assets/JSONAsset.js
@@ -18,7 +18,7 @@ class JSONAsset extends Asset {
       this.ast ? JSON.stringify(this.ast, null, 2) : this.contents
     };`;
 
-    if (this.options.minify) {
+    if (this.options.minify && !this.options.scopeHoist) {
       let minified = minify(code);
       if (minified.error) {
         throw minified.error;
@@ -27,9 +27,7 @@ class JSONAsset extends Asset {
       code = minified.code;
     }
 
-    return {
-      js: code
-    };
+    return code;
   }
 }
 
diff --git a/src/assets/RawAsset.js b/src/assets/RawAsset.js
index 4a1be0cdda5..d44abf2e306 100644
--- a/src/assets/RawAsset.js
+++ b/src/assets/RawAsset.js
@@ -18,9 +18,12 @@ class RawAsset extends Asset {
       this.generateBundleName()
     );
 
-    return {
-      js: `module.exports=${JSON.stringify(pathToAsset)};`
-    };
+    return [
+      {
+        type: 'js',
+        value: `module.exports=${JSON.stringify(pathToAsset)};`
+      }
+    ];
   }
 
   async generateHash() {
diff --git a/src/assets/TOMLAsset.js b/src/assets/TOMLAsset.js
index 10c86dfed6b..ce1d77e8058 100644
--- a/src/assets/TOMLAsset.js
+++ b/src/assets/TOMLAsset.js
@@ -13,9 +13,10 @@ class TOMLAsset extends Asset {
   }
 
   generate() {
-    return {
-      js: serializeObject(this.ast, this.options.minify)
-    };
+    return serializeObject(
+      this.ast,
+      this.options.minify && !this.options.scopeHoist
+    );
   }
 }
 
diff --git a/src/assets/VueAsset.js b/src/assets/VueAsset.js
index a5705dcebde..e68b715f22a 100644
--- a/src/assets/VueAsset.js
+++ b/src/assets/VueAsset.js
@@ -68,8 +68,27 @@ class VueAsset extends Asset {
 
     // Generate JS output.
     let js = this.ast.script ? generated[0].value : '';
-    let supplemental = `
-      var ${optsVar} = exports.default || module.exports;
+    let supplemental = '';
+
+    // TODO: make it possible to process this code with the normal scope hoister
+    if (this.options.scopeHoist) {
+      optsVar = `$${this.id}$export$default`;
+
+      if (!js.includes(optsVar)) {
+        optsVar = `$${this.id}$exports`;
+        if (!js.includes(optsVar)) {
+          supplemental += `
+            var ${optsVar} = {};
+          `;
+
+          this.cacheData.isCommonJS = true;
+        }
+      }
+    } else {
+      supplemental += `var ${optsVar} = exports.default || module.exports;`;
+    }
+
+    supplemental += `
       if (typeof ${optsVar} === 'function') {
         ${optsVar} = ${optsVar}.options;
       }
@@ -79,19 +98,17 @@ class VueAsset extends Asset {
     supplemental += this.compileCSSModules(generated, optsVar);
     supplemental += this.compileHMR(generated, optsVar);
 
-    if (this.options.minify && supplemental) {
+    if (this.options.minify && !this.options.scopeHoist && supplemental) {
       let {code, error} = minify(supplemental, {toplevel: true});
       if (error) {
         throw error;
       }
 
       supplemental = code;
+      if (supplemental) {
+        supplemental = `\n(function(){${supplemental}})();`;
+      }
     }
-
-    if (supplemental) {
-      supplemental = `\n(function(){${supplemental}})();`;
-    }
-
     js += supplemental;
 
     if (js) {
diff --git a/src/assets/YAMLAsset.js b/src/assets/YAMLAsset.js
index 40c904ff6f8..327d7407180 100644
--- a/src/assets/YAMLAsset.js
+++ b/src/assets/YAMLAsset.js
@@ -13,9 +13,10 @@ class YAMLAsset extends Asset {
   }
 
   generate() {
-    return {
-      js: serializeObject(this.ast, this.options.minify)
-    };
+    return serializeObject(
+      this.ast,
+      this.options.minify && !this.options.scopeHoist
+    );
   }
 }
 
diff --git a/src/builtins/.eslintrc.json b/src/builtins/.eslintrc.json
index 3361ed605a0..bbe2667e56c 100644
--- a/src/builtins/.eslintrc.json
+++ b/src/builtins/.eslintrc.json
@@ -7,6 +7,7 @@
     "browser": true
   },
   "rules": {
-    "no-global-assign": 1
+    "no-global-assign": 1,
+    "no-unused-vars": 0
   }
-}
\ No newline at end of file
+}
diff --git a/src/builtins/bundle-loader.js b/src/builtins/bundle-loader.js
index e60c0ae3119..f36878875f7 100644
--- a/src/builtins/bundle-loader.js
+++ b/src/builtins/bundle-loader.js
@@ -12,7 +12,10 @@ function loadBundlesLazy(bundles) {
   } catch (err) {
     if (err.code === 'MODULE_NOT_FOUND') {
       return new LazyPromise(function (resolve, reject) {
-        loadBundles(bundles)
+        loadBundles(bundles.slice(0, -1))
+          .then(function () {
+            return require(id);
+          })
           .then(resolve, reject);
       });
     }
@@ -22,12 +25,7 @@ function loadBundlesLazy(bundles) {
 }
 
 function loadBundles(bundles) {
-  var id = bundles[bundles.length - 1];
-
-  return Promise.all(bundles.slice(0, -1).map(loadBundle))
-    .then(function () {
-      return require(id);
-    });
+  return Promise.all(bundles.map(loadBundle));
 }
 
 var bundleLoaders = {};
@@ -57,9 +55,7 @@ function loadBundle(bundle) {
     return bundles[bundle] = bundleLoader(getBundleURL() + bundle)
       .then(function (resolved) {
         if (resolved) {
-          module.bundle.modules[id] = [function (require, module) {
-            module.exports = resolved;
-          }, {}];
+          module.bundle.register(id, resolved);
         }
 
         return resolved;
diff --git a/src/builtins/helpers.js b/src/builtins/helpers.js
new file mode 100644
index 00000000000..e40bff949d3
--- /dev/null
+++ b/src/builtins/helpers.js
@@ -0,0 +1,30 @@
+function $parcel$interopDefault(a) {
+  return a && a.__esModule
+    ? {d: a.default}
+    : {d: a};
+}
+
+function $parcel$exportWildcard(dest, source) {
+  Object.keys(source).forEach(function(key) {
+    if(key === "default" || key === "__esModule") {
+      return;
+    }
+
+    Object.defineProperty(dest, key, {
+      enumerable: true,
+      get: function get() {
+        return source[key];
+      }
+    });
+  });
+
+  return dest;
+}
+
+function $parcel$missingModule(name) {
+  var err = new Error("Cannot find module '" + name + "'");
+  err.code = 'MODULE_NOT_FOUND';
+  throw err;
+}
+
+var $parcel$global = this;
diff --git a/src/builtins/prelude.js b/src/builtins/prelude.js
index 8463e1c60b2..189d8cba73d 100644
--- a/src/builtins/prelude.js
+++ b/src/builtins/prelude.js
@@ -70,6 +70,11 @@ parcelRequire = (function (modules, cache, entry, globalName) {
   newRequire.modules = modules;
   newRequire.cache = cache;
   newRequire.parent = previousRequire;
+  newRequire.register = function (id, exports) {
+    modules[id] = [function (require, module) {
+      module.exports = exports;
+    }, {}];
+  };
 
   for (var i = 0; i < entry.length; i++) {
     newRequire(entry[i]);
diff --git a/src/builtins/prelude2.js b/src/builtins/prelude2.js
new file mode 100644
index 00000000000..6dcd6d49f10
--- /dev/null
+++ b/src/builtins/prelude2.js
@@ -0,0 +1,45 @@
+parcelRequire = (function (init) {
+  // Save the require from previous bundle to this closure if any
+  var previousRequire = typeof parcelRequire === 'function' && parcelRequire;
+  var nodeRequire = typeof require === 'function' && require;
+  var modules = {};
+
+  function localRequire(name, jumped) {
+    if (name in modules) {
+      return modules[name];
+    }
+
+    // if we cannot find the module within our internal map or
+    // cache jump to the current global require ie. the last bundle
+    // that was added to the page.
+    var currentRequire = typeof parcelRequire === 'function' && parcelRequire;
+    if (!jumped && currentRequire) {
+      return currentRequire(name, true);
+    }
+
+    // If there are other bundles on this page the require from the
+    // previous one is saved to 'previousRequire'. Repeat this as
+    // many times as there are bundles until the module is found or
+    // we exhaust the require chain.
+    if (previousRequire) {
+      return previousRequire(name, true);
+    }
+
+    // Try the node require function if it exists.
+    if (nodeRequire && typeof name === 'string') {
+      return nodeRequire(name);
+    }
+
+    var err = new Error('Cannot find module \'' + name + '\'');
+    err.code = 'MODULE_NOT_FOUND';
+    throw err;
+  }
+
+  localRequire.register = function register(id, exports) {
+    modules[id] = exports;
+  };
+
+  modules = init(localRequire);
+  localRequire.modules = modules;
+  return localRequire;
+})
diff --git a/src/cli.js b/src/cli.js
index bfa36a1345b..6bde994d052 100755
--- a/src/cli.js
+++ b/src/cli.js
@@ -122,6 +122,10 @@ program
   .option('--no-minify', 'disable minification')
   .option('--no-cache', 'disable the filesystem cache')
   .option('--no-source-maps', 'disable sourcemaps')
+  .option(
+    '--experimental-scope-hoisting',
+    'enable experimental scope hoisting/tree shaking support'
+  )
   .option(
     '-t, --target <target>',
     'set the runtime environment, either "node", "browser" or "electron". defaults to "browser"',
@@ -182,6 +186,7 @@ async function bundle(main, command) {
     };
   }
 
+  command.scopeHoist = command.experimentalScopeHoisting || false;
   const bundler = new Bundler(main, command);
 
   command.target = command.target || 'browser';
diff --git a/src/packagers/JSConcatPackager.js b/src/packagers/JSConcatPackager.js
new file mode 100644
index 00000000000..39f27b69750
--- /dev/null
+++ b/src/packagers/JSConcatPackager.js
@@ -0,0 +1,526 @@
+const Packager = require('./Packager');
+const path = require('path');
+const fs = require('fs');
+const concat = require('../scope-hoisting/concat');
+const urlJoin = require('../utils/urlJoin');
+const walk = require('babylon-walk');
+const babylon = require('babylon');
+const t = require('babel-types');
+
+const prelude = fs
+  .readFileSync(path.join(__dirname, '../builtins/prelude2.min.js'), 'utf8')
+  .trim()
+  .replace(/;$/, '');
+const helpers =
+  fs
+    .readFileSync(path.join(__dirname, '../builtins/helpers.js'), 'utf8')
+    .trim() + '\n';
+
+class JSConcatPackager extends Packager {
+  async start() {
+    this.addedAssets = new Set();
+    this.exposedModules = new Set();
+    this.externalModules = new Set();
+    this.size = 0;
+    this.needsPrelude = false;
+    this.statements = [];
+    this.assetPostludes = new Map();
+
+    for (let asset of this.bundle.assets) {
+      // If this module is referenced by another JS bundle, it needs to be exposed externally.
+      let isExposed = !Array.from(asset.parentDeps).every(dep => {
+        let depAsset = this.bundler.loadedAssets.get(dep.parent);
+        return this.bundle.assets.has(depAsset) || depAsset.type !== 'js';
+      });
+
+      if (
+        isExposed ||
+        (this.bundle.entryAsset === asset &&
+          this.bundle.parentBundle &&
+          this.bundle.parentBundle.childBundles.size !== 1)
+      ) {
+        this.exposedModules.add(asset);
+        this.needsPrelude = true;
+      }
+
+      for (let mod of asset.depAssets.values()) {
+        if (
+          !this.bundle.assets.has(mod) &&
+          this.options.bundleLoaders[asset.type]
+        ) {
+          this.needsPrelude = true;
+          break;
+        }
+      }
+    }
+
+    if (this.bundle.entryAsset) {
+      this.markUsedExports(this.bundle.entryAsset);
+    }
+
+    if (this.needsPrelude) {
+      if (
+        this.bundle.entryAsset &&
+        this.options.bundleLoaders[this.bundle.entryAsset.type]
+      ) {
+        this.exposedModules.add(this.bundle.entryAsset);
+      }
+    }
+
+    this.write(helpers);
+  }
+
+  write(string) {
+    this.statements.push(...this.parse(string));
+  }
+
+  getSize() {
+    return this.size;
+  }
+
+  markUsedExports(asset) {
+    if (asset.usedExports) {
+      return;
+    }
+
+    asset.usedExports = new Set();
+
+    for (let identifier in asset.cacheData.imports) {
+      let [source, name] = asset.cacheData.imports[identifier];
+      let dep = asset.depAssets.get(asset.dependencies.get(source));
+      this.markUsed(dep, name);
+    }
+  }
+
+  markUsed(mod, id) {
+    let exp = mod.cacheData.exports[id];
+    if (Array.isArray(exp)) {
+      let depMod = mod.depAssets.get(mod.dependencies.get(exp[0]));
+      return this.markUsed(depMod, exp[1]);
+    }
+
+    this.markUsedExports(mod);
+    mod.usedExports.add(id);
+  }
+
+  getExportIdentifier(asset) {
+    let id = '$' + asset.id + '$exports';
+    if (this.shouldWrap(asset)) {
+      return `($${asset.id}$init(), ${id})`;
+    }
+
+    return id;
+  }
+
+  async addAsset(asset) {
+    if (this.addedAssets.has(asset)) {
+      return;
+    }
+    this.addedAssets.add(asset);
+    let {js} = asset.generated;
+
+    // If the asset's package has the sideEffects: false flag set, and there are no used
+    // exports marked, exclude the asset from the bundle.
+    if (
+      asset.cacheData.sideEffects === false &&
+      (!asset.usedExports || asset.usedExports.size === 0)
+    ) {
+      return;
+    }
+
+    for (let [dep, mod] of asset.depAssets) {
+      if (dep.dynamic && this.bundle.childBundles.has(mod.parentBundle)) {
+        for (let child of mod.parentBundle.siblingBundles) {
+          if (!child.isEmpty) {
+            await this.addBundleLoader(child.type, asset);
+          }
+        }
+
+        await this.addBundleLoader(mod.type, asset, true);
+      } else {
+        // If the dep isn't in this bundle, add it to the list of external modules to preload.
+        // Only do this if this is the root JS bundle, otherwise they will have already been
+        // loaded in parallel with this bundle as part of a dynamic import.
+        if (
+          !this.bundle.assets.has(mod) &&
+          (!this.bundle.parentBundle ||
+            this.bundle.parentBundle.type !== 'js') &&
+          this.options.bundleLoaders[mod.type]
+        ) {
+          this.externalModules.add(mod);
+          await this.addBundleLoader(mod.type, asset);
+        }
+      }
+    }
+
+    // if (this.bundle.entryAsset === asset && this.externalModules.size > 0) {
+    //   js = `
+    //     function $parcel$entry() {
+    //       ${js.trim()}
+    //     }
+    //   `;
+    // }
+
+    // js = js.trim() + '\n';
+    this.size += js.length;
+  }
+
+  shouldWrap(asset) {
+    if (!asset) {
+      return false;
+    }
+
+    if (asset.cacheData.shouldWrap != null) {
+      return asset.cacheData.shouldWrap;
+    }
+
+    // Set to false initially so circular deps work
+    asset.cacheData.shouldWrap = false;
+
+    // We need to wrap if any of the deps are marked by the hoister, e.g.
+    // when the dep is required inside a function or conditional.
+    // We also need to wrap if any of the parents are wrapped - transitive requires
+    // shouldn't be evaluated until their parents are.
+    let shouldWrap = [...asset.parentDeps].some(
+      dep =>
+        dep.shouldWrap ||
+        this.shouldWrap(this.bundler.loadedAssets.get(dep.parent))
+    );
+
+    asset.cacheData.shouldWrap = shouldWrap;
+    return shouldWrap;
+  }
+
+  addDeps(asset, included) {
+    if (!this.bundle.assets.has(asset) || included.has(asset)) {
+      return [];
+    }
+
+    included.add(asset);
+
+    let depAsts = new Map();
+    for (let depAsset of asset.depAssets.values()) {
+      let depAst = this.addDeps(depAsset, included);
+      depAsts.set(depAsset, depAst);
+    }
+
+    let statements;
+    if (
+      asset.cacheData.sideEffects === false &&
+      (!asset.usedExports || asset.usedExports.size === 0)
+    ) {
+      statements = [];
+    } else {
+      statements = this.parse(asset.generated.js, asset.name);
+    }
+
+    if (this.shouldWrap(asset)) {
+      statements = this.wrapModule(asset, statements);
+    }
+
+    if (statements[0]) {
+      if (!statements[0].leadingComments) {
+        statements[0].leadingComments = [];
+      }
+      statements[0].leadingComments.push({
+        type: 'CommentLine',
+        value: ` ASSET: ${path.relative(this.options.rootDir, asset.name)}`
+      });
+    }
+
+    let statementIndices = new Map();
+    for (let i = 0; i < statements.length; i++) {
+      let statement = statements[i];
+      if (t.isExpressionStatement(statement)) {
+        for (let depAsset of this.findRequires(asset, statement)) {
+          if (!statementIndices.has(depAsset)) {
+            statementIndices.set(depAsset, i);
+          }
+        }
+      }
+    }
+
+    let reverseDeps = [...asset.depAssets.values()].reverse();
+    for (let dep of reverseDeps) {
+      let index = statementIndices.has(dep) ? statementIndices.get(dep) : 0;
+      statements.splice(index, 0, ...depAsts.get(dep));
+    }
+
+    if (this.assetPostludes.has(asset)) {
+      statements.push(...this.parse(this.assetPostludes.get(asset)));
+    }
+
+    return statements;
+  }
+
+  wrapModule(asset, statements) {
+    let body = [];
+    let decls = [];
+    let fns = [];
+    for (let node of statements) {
+      // Hoist all declarations out of the function wrapper
+      // so that they can be referenced by other modules directly.
+      if (t.isVariableDeclaration(node)) {
+        for (let decl of node.declarations) {
+          decls.push(t.variableDeclarator(decl.id));
+          if (decl.init) {
+            body.push(
+              t.expressionStatement(
+                t.assignmentExpression(
+                  '=',
+                  t.identifier(decl.id.name),
+                  decl.init
+                )
+              )
+            );
+          }
+        }
+      } else if (t.isFunctionDeclaration(node)) {
+        // Function declarations can be hoisted out of the module initialization function
+        fns.push(node);
+      } else if (t.isClassDeclaration(node)) {
+        // Class declarations are not hoisted. We declare a variable outside the
+        // function convert to a class expression assignment.
+        decls.push(t.variableDeclarator(t.identifier(node.id.name)));
+        body.push(
+          t.expressionStatement(
+            t.assignmentExpression(
+              '=',
+              t.identifier(node.id.name),
+              t.toExpression(node)
+            )
+          )
+        );
+      } else {
+        body.push(node);
+      }
+    }
+
+    let executed = `$${asset.id}$executed`;
+    decls.push(
+      t.variableDeclarator(t.identifier(executed), t.booleanLiteral(false))
+    );
+
+    let init = t.functionDeclaration(
+      t.identifier(`$${asset.id}$init`),
+      [],
+      t.blockStatement([
+        t.ifStatement(t.identifier(executed), t.returnStatement()),
+        t.expressionStatement(
+          t.assignmentExpression(
+            '=',
+            t.identifier(executed),
+            t.booleanLiteral(true)
+          )
+        ),
+        ...body
+      ])
+    );
+
+    return [t.variableDeclaration('var', decls), ...fns, init];
+  }
+
+  parse(code, filename) {
+    let ast = babylon.parse(code, {
+      sourceFilename: filename,
+      allowReturnOutsideFunction: true
+    });
+
+    return ast.program.body;
+  }
+
+  findRequires(asset, ast) {
+    let result = [];
+    walk.simple(ast, {
+      CallExpression(node) {
+        let {arguments: args, callee} = node;
+
+        if (!t.isIdentifier(callee)) {
+          return;
+        }
+
+        if (callee.name === '$parcel$require') {
+          result.push(
+            asset.depAssets.get(asset.dependencies.get(args[1].value))
+          );
+        }
+      }
+    });
+
+    return result;
+  }
+
+  getBundleSpecifier(bundle) {
+    let name = path.basename(bundle.name);
+    if (bundle.entryAsset) {
+      return [name, bundle.entryAsset.id];
+    }
+
+    return name;
+  }
+
+  async addAssetToBundle(asset) {
+    if (this.bundle.assets.has(asset)) {
+      return;
+    }
+    this.bundle.addAsset(asset);
+    if (!asset.parentBundle) {
+      asset.parentBundle = this.bundle;
+    }
+
+    // Add all dependencies as well
+    for (let child of asset.depAssets.values()) {
+      await this.addAssetToBundle(child, this.bundle);
+    }
+
+    await this.addAsset(asset);
+  }
+
+  async addBundleLoader(bundleType, parentAsset, dynamic) {
+    let loader = this.options.bundleLoaders[bundleType];
+    if (!loader) {
+      return;
+    }
+
+    let bundleLoader = this.bundler.loadedAssets.get(
+      require.resolve('../builtins/bundle-loader')
+    );
+    if (!bundleLoader && !dynamic) {
+      bundleLoader = await this.bundler.getAsset('_bundle_loader');
+    }
+
+    if (bundleLoader) {
+      // parentAsset.depAssets.set({name: '_bundle_loader'}, bundleLoader);
+      await this.addAssetToBundle(bundleLoader);
+    } else {
+      return;
+    }
+
+    let target = this.options.target === 'node' ? 'node' : 'browser';
+    let asset = await this.bundler.getAsset(loader[target]);
+    if (!this.bundle.assets.has(asset)) {
+      let dep = {name: asset.name};
+      asset.parentDeps.add(dep);
+      parentAsset.dependencies.set(dep.name, dep);
+      parentAsset.depAssets.set(dep, asset);
+      this.assetPostludes.set(
+        asset,
+        `${this.getExportIdentifier(bundleLoader)}.register(${JSON.stringify(
+          bundleType
+        )},${this.getExportIdentifier(asset)});\n`
+      );
+
+      await this.addAssetToBundle(asset);
+    }
+  }
+
+  async end() {
+    let included = new Set();
+    for (let asset of this.bundle.assets) {
+      this.statements.push(...this.addDeps(asset, included));
+    }
+
+    // Preload external modules before running entry point if needed
+    if (this.externalModules.size > 0) {
+      let bundleLoader = this.bundler.loadedAssets.get(
+        require.resolve('../builtins/bundle-loader')
+      );
+
+      let preload = [];
+      for (let mod of this.externalModules) {
+        // Find the bundle that has the module as its entry point
+        let bundle = Array.from(mod.bundles).find(b => b.entryAsset === mod);
+        if (bundle) {
+          preload.push([path.basename(bundle.name), mod.id]);
+        }
+      }
+
+      let loads = `${this.getExportIdentifier(
+        bundleLoader
+      )}.load(${JSON.stringify(preload)})`;
+      if (this.bundle.entryAsset) {
+        loads += '.then($parcel$entry)';
+      }
+
+      loads += ';';
+      this.write(loads);
+    }
+
+    let entryExports =
+      this.bundle.entryAsset &&
+      this.getExportIdentifier(this.bundle.entryAsset);
+    if (
+      entryExports &&
+      this.bundle.entryAsset.generated.js.includes(entryExports)
+    ) {
+      this.write(`
+        if (typeof exports === "object" && typeof module !== "undefined") {
+          // CommonJS
+          module.exports = ${entryExports};
+        } else if (typeof define === "function" && define.amd) {
+          // RequireJS
+          define(function () {
+            return ${entryExports};
+          });
+        } ${
+          this.options.global
+            ? `else {
+          // <script>
+          this[${JSON.stringify(this.options.global)}] = ${entryExports};
+        }`
+            : ''
+        }
+      `);
+    }
+
+    if (this.needsPrelude) {
+      let exposed = [];
+      let prepareModule = [];
+      for (let m of this.exposedModules) {
+        if (m.cacheData.isES6Module) {
+          prepareModule.push(
+            `${this.getExportIdentifier(m)}.__esModule = true;`
+          );
+        }
+
+        exposed.push(`${m.id}: ${this.getExportIdentifier(m)}`);
+      }
+
+      this.write(`
+        ${prepareModule.join('\n')}
+        return {${exposed.join(', ')}};
+      `);
+    }
+
+    let ast = t.file(t.program(this.statements));
+    let {code: output} = concat(this, ast);
+
+    if (!this.options.minify) {
+      output = '\n' + output + '\n';
+    }
+
+    if (this.needsPrelude) {
+      output = prelude + '(function (require) {' + output + '});';
+    } else {
+      output = '(function () {' + output + '})();';
+    }
+
+    this.bundle.totalSize = output.length;
+
+    let {sourceMaps} = this.options;
+    if (sourceMaps) {
+      // Add source map url if a map bundle exists
+      let mapBundle = this.bundle.siblingBundlesMap.get('map');
+      if (mapBundle) {
+        output += `\n//# sourceMappingURL=${urlJoin(
+          this.options.publicURL,
+          path.basename(mapBundle.name)
+        )}`;
+      }
+    }
+
+    await super.write(output);
+  }
+}
+
+module.exports = JSConcatPackager;
diff --git a/src/packagers/JSPackager.js b/src/packagers/JSPackager.js
index b0436ec0eb5..15c058778be 100644
--- a/src/packagers/JSPackager.js
+++ b/src/packagers/JSPackager.js
@@ -171,11 +171,12 @@ class JSPackager extends Packager {
         }
       }
 
+      loads += 'b.load(' + JSON.stringify(preload) + ')';
       if (this.bundle.entryAsset) {
-        preload.push(this.bundle.entryAsset.id);
+        loads += `.then(function(){require(${this.bundle.entryAsset.id});})`;
       }
 
-      loads += 'b.load(' + JSON.stringify(preload) + ');';
+      loads += ';';
     }
 
     // Asset ids normally start at 1, so this should be safe.
diff --git a/src/packagers/SourceMapPackager.js b/src/packagers/SourceMapPackager.js
index 148c7f84553..1b570d14981 100644
--- a/src/packagers/SourceMapPackager.js
+++ b/src/packagers/SourceMapPackager.js
@@ -16,6 +16,7 @@ class SourceMapPackager extends Packager {
 
   async end() {
     let file = path.basename(this.bundle.name);
+
     await this.write(
       this.sourceMap.stringify(
         file,
diff --git a/src/packagers/index.js b/src/packagers/index.js
index 388c75f56ad..7c6e0b18150 100644
--- a/src/packagers/index.js
+++ b/src/packagers/index.js
@@ -1,3 +1,4 @@
+const JSConcatPackager = require('./JSConcatPackager');
 const JSPackager = require('./JSPackager');
 const CSSPackager = require('./CSSPackager');
 const HTMLPackager = require('./HTMLPackager');
@@ -5,13 +6,13 @@ const SourceMapPackager = require('./SourceMapPackager');
 const RawPackager = require('./RawPackager');
 
 class PackagerRegistry {
-  constructor() {
+  constructor(options) {
     this.packagers = new Map();
 
-    this.add('js', JSPackager);
     this.add('css', CSSPackager);
     this.add('html', HTMLPackager);
     this.add('map', SourceMapPackager);
+    this.add('js', options.scopeHoist ? JSConcatPackager : JSPackager);
   }
 
   add(type, packager) {
diff --git a/src/scope-hoisting/concat.js b/src/scope-hoisting/concat.js
new file mode 100644
index 00000000000..d74b68358aa
--- /dev/null
+++ b/src/scope-hoisting/concat.js
@@ -0,0 +1,394 @@
+const {relative} = require('path');
+const template = require('babel-template');
+const t = require('babel-types');
+const traverse = require('babel-traverse').default;
+const generate = require('babel-generator').default;
+const treeShake = require('./shake');
+const mangleScope = require('./mangler');
+
+const EXPORTS_RE = /^\$([\d]+)\$exports$/;
+
+const DEFAULT_INTEROP_TEMPLATE = template(
+  'var NAME = $parcel$interopDefault(MODULE)'
+);
+const THROW_TEMPLATE = template('$parcel$missingModule(MODULE)');
+const REQUIRE_TEMPLATE = template('require(ID)');
+
+module.exports = (packager, ast) => {
+  let {addedAssets} = packager;
+  let replacements = new Map();
+  let imports = new Map();
+  let referenced = new Set();
+
+  let assets = Array.from(addedAssets).reduce((acc, asset) => {
+    acc[asset.id] = asset;
+
+    return acc;
+  }, {});
+
+  // Build a mapping of all imported identifiers to replace.
+  for (let asset of addedAssets) {
+    for (let name in asset.cacheData.imports) {
+      let imp = asset.cacheData.imports[name];
+      imports.set(name, [resolveModule(asset.id, imp[0]), imp[1]]);
+    }
+  }
+
+  function resolveModule(id, name) {
+    let module = assets[id];
+    return module.depAssets.get(module.dependencies.get(name));
+  }
+
+  function findExportModule(id, name) {
+    let module = assets[id];
+    let exp =
+      module &&
+      Object.prototype.hasOwnProperty.call(module.cacheData.exports, name)
+        ? module.cacheData.exports[name]
+        : null;
+
+    // If this is a re-export, find the original module.
+    if (Array.isArray(exp)) {
+      let mod = resolveModule(id, exp[0]);
+      return findExportModule(mod.id, exp[1]);
+    }
+
+    // If this module exports wildcards, resolve the original module.
+    // Default exports are excluded from wildcard exports.
+    let wildcards = module && module.cacheData.wildcards;
+    if (wildcards && name !== 'default') {
+      for (let source of wildcards) {
+        let m = findExportModule(resolveModule(id, source).id, name);
+        if (m) {
+          return m;
+        }
+      }
+    }
+
+    // If this is a wildcard import, resolve to the exports object.
+    if (module && name === '*') {
+      exp = `$${id}$exports`;
+    }
+
+    if (replacements.has(exp)) {
+      exp = replacements.get(exp);
+    }
+
+    return exp;
+  }
+
+  function replaceExportNode(mod, originalName, path) {
+    let id = mod.id;
+    let res = findExportModule(id, originalName);
+    let node;
+
+    if (res) {
+      node = findSymbol(path, res);
+    }
+
+    // If the module is not in this bundle, create a `require` call for it.
+    if (!node && !assets[id]) {
+      node = REQUIRE_TEMPLATE({ID: t.numericLiteral(id)}).expression;
+      return interop(mod, originalName, path, node);
+    }
+
+    // If this is an ES6 module, throw an error if we cannot resolve the module
+    if (!node && !mod.cacheData.isCommonJS && mod.cacheData.isES6Module) {
+      let relativePath = relative(packager.options.rootDir, mod.name);
+      throw new Error(`${relativePath} does not export '${originalName}'`);
+    }
+
+    // If it is CommonJS, look for an exports object.
+    if (!node && mod.cacheData.isCommonJS) {
+      node = findSymbol(path, `$${id}$exports`);
+      if (!node) {
+        return null;
+      }
+
+      return interop(mod, originalName, path, node);
+    }
+
+    return node;
+  }
+
+  function findSymbol(path, symbol) {
+    if (replacements.has(symbol)) {
+      symbol = replacements.get(symbol);
+    }
+
+    // if the symbol is in the scope there is not need to remap it
+    if (path.scope.getProgramParent().hasBinding(symbol)) {
+      return t.identifier(symbol);
+    }
+
+    return null;
+  }
+
+  function interop(mod, originalName, path, node) {
+    // Handle interop for default imports of CommonJS modules.
+    if (mod.cacheData.isCommonJS && originalName === 'default') {
+      let name = `$${mod.id}$interop$default`;
+      if (!path.scope.getBinding(name)) {
+        let [decl] = path.getStatementParent().insertBefore(
+          DEFAULT_INTEROP_TEMPLATE({
+            NAME: t.identifier(name),
+            MODULE: node
+          })
+        );
+
+        let binding = path.scope.getBinding(`$${mod.id}$exports`);
+        if (binding) {
+          binding.reference(decl.get('declarations.0.init'));
+        }
+
+        path.scope.registerDeclaration(decl);
+      }
+
+      return t.memberExpression(t.identifier(name), t.identifier('d'));
+    }
+
+    // if there is a CommonJS export return $id$exports.name
+    if (originalName !== '*') {
+      return t.memberExpression(node, t.identifier(originalName));
+    }
+
+    return node;
+  }
+
+  function isUnusedValue(path) {
+    return (
+      path.parentPath.isExpressionStatement() ||
+      (path.parentPath.isSequenceExpression() &&
+        (path.key !== path.container.length - 1 ||
+          isUnusedValue(path.parentPath)))
+    );
+  }
+
+  traverse(ast, {
+    CallExpression(path) {
+      let {arguments: args, callee} = path.node;
+
+      if (!t.isIdentifier(callee)) {
+        return;
+      }
+
+      // each require('module') call gets replaced with $parcel$require(id, 'module')
+      if (callee.name === '$parcel$require') {
+        let [id, source] = args;
+
+        if (
+          args.length !== 2 ||
+          !t.isNumericLiteral(id) ||
+          !t.isStringLiteral(source)
+        ) {
+          throw new Error(
+            'invariant: invalid signature, expected : $parcel$require(number, string)'
+          );
+        }
+
+        let mod = resolveModule(id.value, source.value);
+
+        if (!mod) {
+          if (assets[id.value].dependencies.get(source.value).optional) {
+            path.replaceWith(
+              THROW_TEMPLATE({MODULE: t.stringLiteral(source.value)})
+            );
+          } else {
+            throw new Error(
+              `Cannot find module "${source.value}" in asset ${id.value}`
+            );
+          }
+        } else {
+          let node;
+          if (assets[mod.id]) {
+            // Replace with nothing if the require call's result is not used.
+            if (!isUnusedValue(path)) {
+              let name = `$${mod.id}$exports`;
+              node = t.identifier(replacements.get(name) || name);
+            }
+
+            // We need to wrap the module in a function when a require
+            // call happens inside a non top-level scope, e.g. in a
+            // function, if statement, or conditional expression.
+            if (mod.cacheData.shouldWrap) {
+              let call = t.callExpression(t.identifier(`$${mod.id}$init`), []);
+              node = node ? t.sequenceExpression([call, node]) : call;
+            }
+          } else {
+            node = REQUIRE_TEMPLATE({ID: t.numericLiteral(mod.id)}).expression;
+          }
+
+          if (node) {
+            path.replaceWith(node);
+          } else {
+            path.remove();
+          }
+        }
+      } else if (callee.name === '$parcel$require$resolve') {
+        let [id, source] = args;
+
+        if (
+          args.length !== 2 ||
+          !t.isNumericLiteral(id) ||
+          !t.isStringLiteral(source)
+        ) {
+          throw new Error(
+            'invariant: invalid signature, expected : $parcel$require$resolve(number, string)'
+          );
+        }
+
+        let mapped = assets[id.value];
+        let dep = mapped.dependencies.get(source.value);
+        let mod = mapped.depAssets.get(dep);
+        let bundles = mod.id;
+
+        if (dep.dynamic && packager.bundle.childBundles.has(mod.parentBundle)) {
+          bundles = [];
+
+          for (let child of mod.parentBundle.siblingBundles) {
+            if (!child.isEmpty && packager.options.bundleLoaders[child.type]) {
+              bundles.push(packager.getBundleSpecifier(child));
+            }
+          }
+
+          bundles.push(packager.getBundleSpecifier(mod.parentBundle));
+          bundles.push(mod.id);
+        }
+
+        path.replaceWith(t.valueToNode(bundles));
+      }
+    },
+    VariableDeclarator: {
+      exit(path) {
+        // Replace references to declarations like `var x = require('x')`
+        // with the final export identifier instead.
+        // This allows us to potentially replace accesses to e.g. `x.foo` with
+        // a variable like `$id$export$foo` later, avoiding the exports object altogether.
+        let {id, init} = path.node;
+        if (!t.isIdentifier(init)) {
+          return;
+        }
+
+        let match = init.name.match(EXPORTS_RE);
+        if (!match) {
+          return;
+        }
+
+        // Replace patterns like `var {x} = require('y')` with e.g. `$id$export$x`.
+        if (t.isObjectPattern(id)) {
+          for (let p of path.get('id.properties')) {
+            let {computed, key, value} = p.node;
+            if (computed || !t.isIdentifier(key) || !t.isIdentifier(value)) {
+              continue;
+            }
+
+            let exp = findExportModule(match[1], key.name, path);
+            if (exp) {
+              replace(value.name, exp, p);
+            }
+          }
+
+          if (id.properties.length === 0) {
+            path.remove();
+          }
+        } else if (t.isIdentifier(id)) {
+          replace(id.name, init.name, path);
+        }
+
+        function replace(id, init, path) {
+          let binding = path.scope.getBinding(id);
+          if (!binding.constant) {
+            return;
+          }
+
+          for (let ref of binding.referencePaths) {
+            ref.replaceWith(t.identifier(init));
+          }
+
+          replacements.set(id, init);
+          path.remove();
+        }
+      }
+    },
+    MemberExpression: {
+      exit(path) {
+        if (!path.isReferenced()) {
+          return;
+        }
+
+        let {object, property, computed} = path.node;
+        if (
+          !(
+            t.isIdentifier(object) &&
+            ((t.isIdentifier(property) && !computed) ||
+              t.isStringLiteral(property))
+          )
+        ) {
+          return;
+        }
+
+        let match = object.name.match(EXPORTS_RE);
+
+        // If it's a $id$exports.name expression.
+        if (match) {
+          let name = t.isIdentifier(property) ? property.name : property.value;
+          let exp = findExportModule(match[1], name, path);
+
+          // Check if $id$export$name exists and if so, replace the node by it.
+          if (exp) {
+            path.replaceWith(t.identifier(exp));
+          }
+        }
+      }
+    },
+    ReferencedIdentifier(path) {
+      let {name} = path.node;
+
+      if (typeof name !== 'string') {
+        return;
+      }
+
+      if (imports.has(name)) {
+        let imp = imports.get(name);
+        let node = replaceExportNode(imp[0], imp[1], path);
+
+        // If the export does not exist, replace with an empty object.
+        if (!node) {
+          node = t.objectExpression([]);
+        }
+
+        path.replaceWith(node);
+        return;
+      }
+
+      let match = name.match(EXPORTS_RE);
+      if (match) {
+        referenced.add(name);
+      }
+
+      // If it's an undefined $id$exports identifier.
+      if (match && !path.scope.hasBinding(name)) {
+        path.replaceWith(t.objectExpression([]));
+      }
+    },
+    Program: {
+      // A small optimization to remove unused CommonJS exports as sometimes Uglify doesn't remove them.
+      exit(path) {
+        treeShake(path.scope);
+
+        if (packager.options.minify) {
+          mangleScope(path.scope);
+        }
+      }
+    }
+  });
+
+  let opts = {
+    sourceMaps: packager.options.sourceMaps,
+    sourceFileName: packager.bundle.name,
+    minified: packager.options.minify,
+    comments: !packager.options.minify
+  };
+
+  return generate(ast, opts);
+};
diff --git a/src/scope-hoisting/hoist.js b/src/scope-hoisting/hoist.js
new file mode 100644
index 00000000000..96b1c6e1852
--- /dev/null
+++ b/src/scope-hoisting/hoist.js
@@ -0,0 +1,570 @@
+const matchesPattern = require('../visitors/matches-pattern');
+const t = require('babel-types');
+const template = require('babel-template');
+const rename = require('./renamer');
+
+const WRAPPER_TEMPLATE = template(`
+  var NAME = (function () {
+    var exports = this;
+    var module = {exports: this};
+    BODY;
+    return module.exports;
+  }).call({});
+`);
+
+const ESMODULE_TEMPLATE = template(`exports.__esModule = true;`);
+
+const EXPORT_ASSIGN_TEMPLATE = template('EXPORTS.NAME = LOCAL');
+const EXPORT_ALL_TEMPLATE = template(
+  '$parcel$exportWildcard(OLD_NAME, $parcel$require(ID, SOURCE))'
+);
+const REQUIRE_CALL_TEMPLATE = template('$parcel$require(ID, SOURCE)');
+const REQUIRE_RESOLVE_CALL_TEMPLATE = template(
+  '$parcel$require$resolve(ID, SOURCE)'
+);
+const TYPEOF = {
+  module: 'object',
+  require: 'function'
+};
+
+module.exports = {
+  Program: {
+    enter(path, asset) {
+      asset.cacheData.imports = asset.cacheData.imports || Object.create(null);
+      asset.cacheData.exports = asset.cacheData.exports || Object.create(null);
+      asset.cacheData.wildcards = asset.cacheData.wildcards || [];
+      asset.cacheData.sideEffects =
+        asset._package && asset._package.sideEffects;
+
+      let shouldWrap = false;
+      path.traverse({
+        CallExpression(path) {
+          // If we see an `eval` call, wrap the module in a function.
+          // Otherwise, local variables accessed inside the eval won't work.
+          let callee = path.node.callee;
+          if (
+            t.isIdentifier(callee) &&
+            callee.name === 'eval' &&
+            !path.scope.hasBinding('eval', true)
+          ) {
+            asset.cacheData.isCommonJS = true;
+            shouldWrap = true;
+            path.stop();
+          }
+        },
+
+        ReturnStatement(path) {
+          // Wrap in a function if we see a top-level return statement.
+          if (path.getFunctionParent().isProgram()) {
+            shouldWrap = true;
+            asset.cacheData.isCommonJS = true;
+            path.replaceWith(
+              t.returnStatement(
+                t.memberExpression(
+                  t.identifier('module'),
+                  t.identifier('exports')
+                )
+              )
+            );
+            path.stop();
+          }
+        },
+
+        ReferencedIdentifier(path) {
+          // We must wrap if `module` is referenced as a free identifier rather
+          // than a statically resolvable member expression.
+          if (
+            path.node.name === 'module' &&
+            (!path.parentPath.isMemberExpression() || path.parent.computed) &&
+            !(
+              path.parentPath.isUnaryExpression() &&
+              path.parent.operator === 'typeof'
+            ) &&
+            !path.scope.hasBinding('module') &&
+            !path.scope.getData('shouldWrap')
+          ) {
+            asset.cacheData.isCommonJS = true;
+            shouldWrap = true;
+            path.stop();
+          }
+        }
+      });
+
+      path.scope.setData('shouldWrap', shouldWrap);
+    },
+
+    exit(path, asset) {
+      let scope = path.scope;
+
+      if (scope.getData('shouldWrap')) {
+        if (asset.cacheData.isES6Module) {
+          path.unshiftContainer('body', [ESMODULE_TEMPLATE()]);
+        }
+
+        path.replaceWith(
+          t.program([
+            WRAPPER_TEMPLATE({
+              NAME: getExportsIdentifier(asset),
+              BODY: path.node.body
+            })
+          ])
+        );
+
+        asset.cacheData.isCommonJS = true;
+        asset.cacheData.isES6Module = false;
+      } else {
+        // Re-crawl scope so we are sure to have all bindings.
+        scope.crawl();
+
+        // Rename each binding in the top-level scope to something unique.
+        for (let name in scope.bindings) {
+          if (!name.startsWith('$' + asset.id)) {
+            let newName = '$' + asset.id + '$var$' + name;
+            rename(scope, name, newName);
+          }
+        }
+
+        let exportsIdentifier = getExportsIdentifier(asset);
+
+        // Add variable that represents module.exports if it is referenced and not declared.
+        if (
+          scope.hasGlobal(exportsIdentifier.name) &&
+          !scope.hasBinding(exportsIdentifier.name)
+        ) {
+          scope.push({id: exportsIdentifier, init: t.objectExpression([])});
+        }
+      }
+
+      path.stop();
+      asset.isAstDirty = true;
+    }
+  },
+
+  DirectiveLiteral(path) {
+    // Remove 'use strict' directives, since modules are concatenated - one strict mode
+    // module should not apply to all other modules in the same scope.
+    if (path.node.value === 'use strict') {
+      path.parentPath.remove();
+    }
+  },
+
+  MemberExpression(path, asset) {
+    if (path.scope.hasBinding('module') || path.scope.getData('shouldWrap')) {
+      return;
+    }
+
+    if (matchesPattern(path.node, 'module.exports')) {
+      path.replaceWith(getExportsIdentifier(asset));
+      asset.cacheData.isCommonJS = true;
+    }
+
+    if (matchesPattern(path.node, 'module.id')) {
+      path.replaceWith(t.numericLiteral(asset.id));
+    }
+
+    if (matchesPattern(path.node, 'module.hot')) {
+      path.replaceWith(t.identifier('null'));
+    }
+
+    if (matchesPattern(path.node, 'module.bundle')) {
+      path.replaceWith(t.identifier('require'));
+    }
+  },
+
+  ReferencedIdentifier(path, asset) {
+    if (
+      path.node.name === 'exports' &&
+      !path.scope.hasBinding('exports') &&
+      !path.scope.getData('shouldWrap')
+    ) {
+      path.replaceWith(getExportsIdentifier(asset));
+      asset.cacheData.isCommonJS = true;
+    }
+
+    if (path.node.name === 'global' && !path.scope.hasBinding('global')) {
+      path.replaceWith(t.identifier('$parcel$global'));
+      asset.globals.delete('global');
+    }
+
+    let globalCode = asset.globals.get(path.node.name);
+    if (globalCode) {
+      path.scope
+        .getProgramParent()
+        .path.unshiftContainer('body', [template(globalCode)()]);
+
+      asset.globals.delete(path.node.name);
+    }
+  },
+
+  ThisExpression(path, asset) {
+    if (!path.scope.parent && !path.scope.getData('shouldWrap')) {
+      path.replaceWith(getExportsIdentifier(asset));
+      asset.cacheData.isCommonJS = true;
+    }
+  },
+
+  AssignmentExpression(path, asset) {
+    if (path.scope.hasBinding('exports') || path.scope.getData('shouldWrap')) {
+      return;
+    }
+
+    let {left, right} = path.node;
+    if (t.isIdentifier(left) && left.name === 'exports') {
+      path.get('left').replaceWith(getExportsIdentifier(asset));
+      asset.cacheData.isCommonJS = true;
+    }
+
+    // If we can statically evaluate the name of a CommonJS export, create an ES6-style export for it.
+    // This allows us to remove the CommonJS export object completely in many cases.
+    if (
+      t.isMemberExpression(left) &&
+      t.isIdentifier(left.object, {name: 'exports'}) &&
+      ((t.isIdentifier(left.property) && !left.computed) ||
+        t.isStringLiteral(left.property))
+    ) {
+      let name = t.isIdentifier(left.property)
+        ? left.property.name
+        : left.property.value;
+      let identifier = getExportIdentifier(asset, name);
+
+      // Replace the CommonJS assignment with a reference to the ES6 identifier.
+      path.get('left.object').replaceWith(getExportsIdentifier(asset));
+      path.get('right').replaceWith(identifier);
+
+      // If this is the first assignment, create a binding for the ES6-style export identifier.
+      // Otherwise, assign to the existing export binding.
+      let scope = path.scope.getProgramParent();
+      if (!scope.hasBinding(identifier.name)) {
+        asset.cacheData.exports[name] = identifier.name;
+        let [decl] = path.insertBefore(
+          t.variableDeclaration('var', [
+            t.variableDeclarator(t.clone(identifier), right)
+          ])
+        );
+
+        scope.registerDeclaration(decl);
+      } else {
+        path.insertBefore(
+          t.assignmentExpression('=', t.clone(identifier), right)
+        );
+      }
+
+      asset.cacheData.isCommonJS = true;
+    }
+  },
+
+  UnaryExpression(path) {
+    // Replace `typeof module` with "object"
+    if (
+      path.node.operator === 'typeof' &&
+      t.isIdentifier(path.node.argument) &&
+      TYPEOF[path.node.argument.name] &&
+      !path.scope.hasBinding(path.node.argument.name) &&
+      !path.scope.getData('shouldWrap')
+    ) {
+      path.replaceWith(t.stringLiteral(TYPEOF[path.node.argument.name]));
+    }
+  },
+
+  CallExpression(path, asset) {
+    let {callee, arguments: args} = path.node;
+    let ignore =
+      args.length !== 1 ||
+      !t.isStringLiteral(args[0]) ||
+      path.scope.hasBinding('require');
+
+    if (ignore) {
+      return;
+    }
+
+    if (t.isIdentifier(callee, {name: 'require'})) {
+      // Ignore require calls that were ignored earlier.
+      if (!asset.dependencies.has(args[0].value)) {
+        return;
+      }
+
+      // If this require call does not occur in the top-level, e.g. in a function
+      // or inside an if statement, or if it might potentially happen conditionally,
+      // the module must be wrapped in a function so that the module execution order is correct.
+      let parent = path.getStatementParent().parentPath;
+      let bail = path.findParent(
+        p =>
+          p.isConditionalExpression() ||
+          p.isLogicalExpression() ||
+          p.isSequenceExpression()
+      );
+      if (!parent.isProgram() || bail) {
+        asset.dependencies.get(args[0].value).shouldWrap = true;
+      }
+
+      // Generate a variable name based on the current asset id and the module name to require.
+      // This will be replaced by the final variable name of the resolved asset in the packager.
+      path.replaceWith(
+        REQUIRE_CALL_TEMPLATE({
+          ID: t.numericLiteral(asset.id),
+          SOURCE: t.stringLiteral(args[0].value)
+        })
+      );
+    }
+
+    if (matchesPattern(callee, 'require.resolve')) {
+      path.replaceWith(
+        REQUIRE_RESOLVE_CALL_TEMPLATE({
+          ID: t.numericLiteral(asset.id),
+          SOURCE: args[0]
+        })
+      );
+    }
+  },
+
+  ImportDeclaration(path, asset) {
+    // For each specifier, rename the local variables to point to the imported name.
+    // This will be replaced by the final variable name of the resolved asset in the packager.
+    for (let specifier of path.node.specifiers) {
+      let id = getIdentifier(asset, 'import', specifier.local.name);
+      rename(path.scope, specifier.local.name, id.name);
+
+      if (t.isImportDefaultSpecifier(specifier)) {
+        asset.cacheData.imports[id.name] = [path.node.source.value, 'default'];
+      } else if (t.isImportSpecifier(specifier)) {
+        asset.cacheData.imports[id.name] = [
+          path.node.source.value,
+          specifier.imported.name
+        ];
+      } else if (t.isImportNamespaceSpecifier(specifier)) {
+        asset.cacheData.imports[id.name] = [path.node.source.value, '*'];
+      }
+    }
+
+    addImport(asset, path);
+    path.remove();
+  },
+
+  ExportDefaultDeclaration(path, asset) {
+    let {declaration} = path.node;
+    let identifier = getExportIdentifier(asset, 'default');
+
+    let name = declaration.id ? declaration.id.name : declaration.name;
+
+    if (asset.cacheData.imports[name]) {
+      asset.cacheData.exports['default'] = asset.cacheData.imports[name];
+      identifier = t.identifier(name);
+    }
+
+    if (hasExport(asset, name)) {
+      identifier = t.identifier(name);
+    }
+
+    // Add assignment to exports object for namespace imports and commonjs.
+    path.insertAfter(
+      EXPORT_ASSIGN_TEMPLATE({
+        EXPORTS: getExportsIdentifier(asset, path.scope),
+        NAME: t.identifier('default'),
+        LOCAL: t.clone(identifier)
+      })
+    );
+
+    if (t.isIdentifier(declaration)) {
+      // Rename the variable being exported.
+      safeRename(path, asset, declaration.name, identifier.name);
+      path.remove();
+    } else if (t.isExpression(declaration) || !declaration.id) {
+      // Declare a variable to hold the exported value.
+      path.replaceWith(
+        t.variableDeclaration('var', [
+          t.variableDeclarator(identifier, t.toExpression(declaration))
+        ])
+      );
+
+      path.scope.registerDeclaration(path);
+    } else {
+      // Rename the declaration to the exported name.
+      safeRename(path, asset, declaration.id.name, identifier.name);
+      path.replaceWith(declaration);
+    }
+
+    if (!asset.cacheData.exports['default']) {
+      asset.cacheData.exports['default'] = identifier.name;
+    }
+
+    // Mark the asset as an ES6 module, so we handle imports correctly in the packager.
+    asset.cacheData.isES6Module = true;
+  },
+
+  ExportNamedDeclaration(path, asset) {
+    let {declaration, source, specifiers} = path.node;
+
+    if (source) {
+      for (let specifier of specifiers) {
+        let exported = specifier.exported;
+
+        if (t.isExportDefaultSpecifier(specifier)) {
+          asset.cacheData.exports[exported.name] = [source.value, 'default'];
+        } else if (t.isExportNamespaceSpecifier(specifier)) {
+          asset.cacheData.exports[exported.name] = [source.value, '*'];
+        } else if (t.isExportSpecifier(specifier)) {
+          asset.cacheData.exports[exported.name] = [
+            source.value,
+            specifier.local.name
+          ];
+        }
+
+        let id = getIdentifier(asset, 'import', exported.name);
+        asset.cacheData.imports[id.name] =
+          asset.cacheData.exports[exported.name];
+
+        path.insertAfter(
+          EXPORT_ASSIGN_TEMPLATE({
+            EXPORTS: getExportsIdentifier(asset, path.scope),
+            NAME: exported,
+            LOCAL: id
+          })
+        );
+      }
+
+      addImport(asset, path);
+      path.remove();
+    } else if (declaration) {
+      path.replaceWith(declaration);
+
+      let identifiers = t.isIdentifier(declaration.id)
+        ? [declaration.id]
+        : t.getBindingIdentifiers(declaration);
+
+      for (let id in identifiers) {
+        addExport(asset, path, identifiers[id], identifiers[id]);
+      }
+    } else if (specifiers.length > 0) {
+      for (let specifier of specifiers) {
+        addExport(asset, path, specifier.local, specifier.exported);
+      }
+
+      path.remove();
+    }
+
+    // Mark the asset as an ES6 module, so we handle imports correctly in the packager.
+    asset.cacheData.isES6Module = true;
+  },
+
+  ExportAllDeclaration(path, asset) {
+    asset.cacheData.wildcards.push(path.node.source.value);
+    asset.cacheData.isES6Module = true;
+
+    path.replaceWith(
+      EXPORT_ALL_TEMPLATE({
+        OLD_NAME: getExportsIdentifier(asset),
+        SOURCE: t.stringLiteral(path.node.source.value),
+        ID: t.numericLiteral(asset.id)
+      })
+    );
+  }
+};
+
+function addImport(asset, path) {
+  // Replace with a $parcel$require call so we know where to insert side effects.
+  let requireCall = REQUIRE_CALL_TEMPLATE({
+    ID: t.numericLiteral(asset.id),
+    SOURCE: t.stringLiteral(path.node.source.value)
+  });
+
+  // Hoist the call to the top of the file.
+  let lastImport = path.scope.getData('hoistedImport');
+  if (lastImport) {
+    [lastImport] = lastImport.insertAfter(requireCall);
+  } else {
+    [lastImport] = path.parentPath.unshiftContainer('body', [requireCall]);
+  }
+
+  path.scope.setData('hoistedImport', lastImport);
+}
+
+function addExport(asset, path, local, exported) {
+  let scope = path.scope.getProgramParent();
+  let identifier = getExportIdentifier(asset, exported.name);
+
+  if (asset.cacheData.imports[local.name]) {
+    asset.cacheData.exports[exported.name] =
+      asset.cacheData.imports[local.name];
+    identifier = t.identifier(local.name);
+  }
+
+  if (hasExport(asset, local.name)) {
+    identifier = t.identifier(local.name);
+  }
+
+  let assignNode = EXPORT_ASSIGN_TEMPLATE({
+    EXPORTS: getExportsIdentifier(asset, scope),
+    NAME: t.identifier(exported.name),
+    LOCAL: identifier
+  });
+
+  let constantViolations = scope
+    .getBinding(local.name)
+    .constantViolations.concat(path);
+
+  if (!asset.cacheData.exports[exported.name]) {
+    asset.cacheData.exports[exported.name] = identifier.name;
+  }
+
+  rename(scope, local.name, identifier.name);
+
+  constantViolations.forEach(path => path.insertAfter(t.cloneDeep(assignNode)));
+}
+
+function hasExport(asset, name) {
+  let exports = asset.cacheData.exports;
+  return Object.keys(exports).some(k => exports[k] === name);
+}
+
+function safeRename(path, asset, from, to) {
+  if (from === to) {
+    return;
+  }
+
+  // If the binding that we're renaming is constant, it's safe to rename it.
+  // Otherwise, create a new binding that references the original.
+  let binding = path.scope.getBinding(from);
+  if (binding && binding.constant) {
+    rename(path.scope, from, to);
+  } else {
+    let [decl] = path.insertAfter(
+      t.variableDeclaration('var', [
+        t.variableDeclarator(t.identifier(to), t.identifier(from))
+      ])
+    );
+
+    path.scope.getBinding(from).reference(decl.get('declarations.0.init'));
+    path.scope.registerDeclaration(decl);
+  }
+}
+
+function getName(asset, type, ...rest) {
+  return (
+    '$' +
+    asset.id +
+    '$' +
+    type +
+    (rest.length
+      ? '$' +
+        rest
+          .map(name => (name === 'default' ? name : t.toIdentifier(name)))
+          .join('$')
+      : '')
+  );
+}
+
+function getIdentifier(asset, type, ...rest) {
+  return t.identifier(getName(asset, type, ...rest));
+}
+
+function getExportIdentifier(asset, name) {
+  return getIdentifier(asset, 'export', name);
+}
+
+function getExportsIdentifier(asset, scope) {
+  if (scope && scope.getData('shouldWrap')) {
+    return t.identifier('exports');
+  } else {
+    return getIdentifier(asset, 'exports');
+  }
+}
diff --git a/src/scope-hoisting/mangler.js b/src/scope-hoisting/mangler.js
new file mode 100644
index 00000000000..f2bac52f35e
--- /dev/null
+++ b/src/scope-hoisting/mangler.js
@@ -0,0 +1,69 @@
+const rename = require('./renamer');
+const t = require('babel-types');
+
+const CHARSET = (
+  'abcdefghijklmnopqrstuvwxyz' + 'ABCDEFGHIJKLMNOPQRSTUVWXYZ$_'
+).split('');
+
+/**
+ * This is a very specialized mangler designer to mangle only names in the top-level scope.
+ * Mangling of names in other scopes happens at a file level inside workers, but we can't
+ * mangle the top-level scope until scope hoisting is complete in the packager.
+ */
+function mangleScope(scope) {
+  let newNames = new Set();
+
+  // Sort bindings so that more frequently referenced bindings get shorter names.
+  let sortedBindings = Object.keys(scope.bindings).sort(
+    (a, b) =>
+      scope.bindings[b].referencePaths.length -
+      scope.bindings[a].referencePaths.length
+  );
+
+  for (let oldName of sortedBindings) {
+    let i = 0;
+    let newName = '';
+
+    do {
+      newName = getIdentifier(i++);
+    } while (
+      newNames.has(newName) ||
+      !canRename(scope, scope.bindings[oldName], newName)
+    );
+
+    rename(scope, oldName, newName);
+    newNames.add(newName);
+  }
+}
+
+function getIdentifier(num) {
+  let ret = '';
+  num++;
+
+  do {
+    num--;
+    ret += CHARSET[num % CHARSET.length];
+    num = Math.floor(num / CHARSET.length);
+  } while (num > 0);
+
+  return ret;
+}
+
+function canRename(scope, binding, newName) {
+  if (!t.isValidIdentifier(newName)) {
+    return false;
+  }
+
+  // If there are any references where the parent scope has a binding
+  // for the new name, we cannot rename to this name.
+  for (let i = 0; i < binding.referencePaths.length; i++) {
+    const ref = binding.referencePaths[i];
+    if (ref.scope.hasBinding(newName) || ref.scope.hasReference(newName)) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+module.exports = mangleScope;
diff --git a/src/scope-hoisting/renamer.js b/src/scope-hoisting/renamer.js
new file mode 100644
index 00000000000..288e9adbb37
--- /dev/null
+++ b/src/scope-hoisting/renamer.js
@@ -0,0 +1,33 @@
+function rename(scope, oldName, newName) {
+  if (oldName === newName) {
+    return;
+  }
+
+  let binding = scope.getBinding(oldName);
+
+  // Rename all constant violations
+  for (let violation of binding.constantViolations) {
+    let bindingIds = violation.getBindingIdentifierPaths(true, false);
+    for (let name in bindingIds) {
+      if (name === oldName) {
+        for (let idPath of bindingIds[name]) {
+          idPath.node.name = newName;
+        }
+      }
+    }
+  }
+
+  // Rename all references
+  for (let path of binding.referencePaths) {
+    if (path.node.name === oldName) {
+      path.node.name = newName;
+    }
+  }
+
+  // Rename binding identifier, and update scope.
+  binding.identifier.name = newName;
+  scope.bindings[newName] = binding;
+  delete scope.bindings[oldName];
+}
+
+module.exports = rename;
diff --git a/src/scope-hoisting/shake.js b/src/scope-hoisting/shake.js
new file mode 100644
index 00000000000..3133b52dc1b
--- /dev/null
+++ b/src/scope-hoisting/shake.js
@@ -0,0 +1,126 @@
+const t = require('babel-types');
+
+const EXPORTS_RE = /^\$([\d]+)\$exports$/;
+
+/**
+ * This is a small small implementation of dead code removal specialized to handle
+ * removing unused exports. All other dead code removal happens in workers on each
+ * individual file by babel-minify.
+ */
+function treeShake(scope) {
+  // Keep passing over all bindings in the scope until we don't remove any.
+  // This handles cases where we remove one binding which had a reference to
+  // another one. That one will get removed in the next pass if it is now unreferenced.
+  let removed;
+  do {
+    removed = false;
+
+    // Recrawl to get all bindings.
+    scope.crawl();
+    Object.keys(scope.bindings).forEach(name => {
+      let binding = getUnusedBinding(scope.path, name);
+
+      // If it is not safe to remove the binding don't touch it.
+      if (!binding) {
+        return;
+      }
+
+      // Remove the binding and all references to it.
+      binding.path.remove();
+      binding.referencePaths
+        .concat(binding.constantViolations)
+        .forEach(path => {
+          if (path.parentPath.isMemberExpression()) {
+            let parent = path.parentPath.parentPath;
+            if (
+              parent.parentPath.isSequenceExpression() &&
+              parent.parent.expressions.length === 1
+            ) {
+              parent.parentPath.remove();
+            } else if (!parent.removed) {
+              parent.remove();
+            }
+          } else if (isUnusedWildcard(path) && !path.parentPath.removed) {
+            path.parentPath.remove();
+          } else if (path.isAssignmentExpression()) {
+            let parent = path.parentPath;
+            if (!parent.isExpressionStatement()) {
+              path.replaceWith(path.node.right);
+            } else {
+              path.remove();
+            }
+          }
+        });
+
+      scope.removeBinding(name);
+      removed = true;
+    });
+  } while (removed);
+}
+
+module.exports = treeShake;
+
+// Check if a binding is safe to remove and returns it if it is.
+function getUnusedBinding(path, name) {
+  let binding = path.scope.getBinding(name);
+  if (!binding) {
+    return null;
+  }
+
+  if (isPure(binding)) {
+    return binding;
+  }
+
+  if (!EXPORTS_RE.test(name)) {
+    return null;
+  }
+
+  // Is there any references which aren't simple assignments?
+  let bailout = binding.referencePaths.some(
+    path => !isExportAssignment(path) && !isUnusedWildcard(path)
+  );
+
+  if (bailout) {
+    return null;
+  } else {
+    return binding;
+  }
+}
+
+function isPure(binding) {
+  if (binding.referenced) {
+    return false;
+  }
+
+  if (
+    binding.path.isVariableDeclarator() &&
+    binding.path.get('id').isIdentifier()
+  ) {
+    let init = binding.path.get('init');
+    return init.isPure() || init.isIdentifier() || init.isThisExpression();
+  }
+
+  return binding.path.isPure();
+}
+
+function isExportAssignment(path) {
+  return (
+    // match "path.any = any;"
+    path.parentPath.isMemberExpression() &&
+    path.parentPath.parentPath.isAssignmentExpression() &&
+    path.parentPath.parentPath.node.left === path.parentPath.node
+  );
+}
+
+function isUnusedWildcard(path) {
+  let {parent} = path;
+
+  return (
+    // match `$parcel$exportWildcard` calls
+    t.isCallExpression(parent) &&
+    t.isIdentifier(parent.callee, {name: '$parcel$exportWildcard'}) &&
+    parent.arguments[0] === path.node &&
+    // check if the $id$exports variable is used
+    !getUnusedBinding(path, parent.arguments[1].name)
+  );
+}
diff --git a/src/transforms/terser.js b/src/transforms/terser.js
index b9ae9295827..ddd2470c572 100644
--- a/src/transforms/terser.js
+++ b/src/transforms/terser.js
@@ -11,7 +11,7 @@ module.exports = async function(asset) {
   let options = {
     warnings: true,
     mangle: {
-      toplevel: true
+      toplevel: !asset.options.scopeHoist
     }
   };
 
diff --git a/src/visitors/globals.js b/src/visitors/globals.js
index f84cde3028d..b947081950a 100644
--- a/src/visitors/globals.js
+++ b/src/visitors/globals.js
@@ -6,7 +6,8 @@ const VARS = {
     asset.addDependency('process');
     return 'var process = require("process");';
   },
-  global: () => 'var global = arguments[3];',
+  global: asset =>
+    `var global = arguments[${asset.options.scopeHoist ? 0 : 3}];`,
   __dirname: asset =>
     `var __dirname = ${JSON.stringify(Path.dirname(asset.name))};`,
   __filename: asset => `var __filename = ${JSON.stringify(asset.name)};`,
diff --git a/src/worker.js b/src/worker.js
index 1c093dbaa85..cb607f58951 100644
--- a/src/worker.js
+++ b/src/worker.js
@@ -18,9 +18,9 @@ function init(options) {
   process.env.HMR_HOSTNAME = options.hmrHostname;
 }
 
-async function run(path, isWarmUp) {
+async function run(path, id, isWarmUp) {
   try {
-    return await pipeline.process(path, isWarmUp);
+    return await pipeline.process(path, id, isWarmUp);
   } catch (e) {
     e.fileName = path;
     throw e;
diff --git a/test/fs.js b/test/fs.js
index 1f9f49d84c1..b5c2edb40b1 100644
--- a/test/fs.js
+++ b/test/fs.js
@@ -13,7 +13,7 @@ describe('fs', function() {
     it('should inline a file as a buffer', async function() {
       let b = await bundle(__dirname + '/integration/fs-buffer/index.js');
       let output = await run(b);
-      assert.equal(output.constructor.name, 'Buffer');
+      assert(output.constructor.name.includes('Buffer'));
       assert.equal(output.length, 5);
     });
 
@@ -87,7 +87,7 @@ describe('fs', function() {
       try {
         await run(b);
       } catch (e) {
-        assert.equal(e.message, 'require(...).readFileSync is not a function');
+        assert(e.message.includes('.readFileSync is not a function'));
 
         thrown = true;
       }
@@ -104,7 +104,7 @@ describe('fs', function() {
       try {
         await run(b);
       } catch (e) {
-        assert.equal(e.message, 'require(...).readFileSync is not a function');
+        assert(e.message.includes('.readFileSync is not a function'));
 
         thrown = true;
       }
diff --git a/test/integration/circular/about.js b/test/integration/circular/about.js
index 0423432d88b..27f8a48c2b7 100644
--- a/test/integration/circular/about.js
+++ b/test/integration/circular/about.js
@@ -1,2 +1,6 @@
 // eslint-disable-next-line no-unused-vars
 import index from './index';
+
+export default function () {
+  index();
+}
diff --git a/test/integration/circular/index.js b/test/integration/circular/index.js
index 86716399365..9cbf6c6508a 100644
--- a/test/integration/circular/index.js
+++ b/test/integration/circular/index.js
@@ -1,2 +1,6 @@
 // eslint-disable-next-line no-unused-vars
 import about from './about';
+
+export default function () {
+  about();
+}
diff --git a/test/integration/scope-hoisting/commonjs/default-import/a.js b/test/integration/scope-hoisting/commonjs/default-import/a.js
new file mode 100644
index 00000000000..0b1fbc04f48
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/default-import/a.js
@@ -0,0 +1,3 @@
+import foo from './b';
+
+output = foo;
diff --git a/test/integration/scope-hoisting/commonjs/default-import/b.js b/test/integration/scope-hoisting/commonjs/default-import/b.js
new file mode 100644
index 00000000000..4bbffde1044
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/default-import/b.js
@@ -0,0 +1 @@
+module.exports = 2;
diff --git a/test/integration/scope-hoisting/commonjs/define-exports/a.js b/test/integration/scope-hoisting/commonjs/define-exports/a.js
new file mode 100644
index 00000000000..5793ac2853d
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/define-exports/a.js
@@ -0,0 +1,7 @@
+export const foo = 'bar'
+
+export function getExports() {
+    return exports
+}
+
+output = getExports() === exports && getExports().foo
diff --git a/test/integration/scope-hoisting/commonjs/eliminate-exports/a.js b/test/integration/scope-hoisting/commonjs/eliminate-exports/a.js
new file mode 100644
index 00000000000..32d2012d4ac
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/eliminate-exports/a.js
@@ -0,0 +1,4 @@
+var b = require('./b');
+
+b.setFoo(3);
+module.exports = b.foo + b['bar'];
diff --git a/test/integration/scope-hoisting/commonjs/eliminate-exports/b.js b/test/integration/scope-hoisting/commonjs/eliminate-exports/b.js
new file mode 100644
index 00000000000..64dc2535ae8
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/eliminate-exports/b.js
@@ -0,0 +1,6 @@
+exports.foo = 2;
+exports['bar'] = 3;
+
+exports.setFoo = function (foo) {
+  exports.foo = foo;
+};
diff --git a/test/integration/scope-hoisting/commonjs/empty-module/a.js b/test/integration/scope-hoisting/commonjs/empty-module/a.js
new file mode 100644
index 00000000000..5ab80db97f1
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/empty-module/a.js
@@ -0,0 +1,3 @@
+module.exports = {
+  b: require('./b')
+};
diff --git a/test/integration/scope-hoisting/commonjs/empty-module/b.js b/test/integration/scope-hoisting/commonjs/empty-module/b.js
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/test/integration/scope-hoisting/commonjs/es6-commonjs-hybrid/a.js b/test/integration/scope-hoisting/commonjs/es6-commonjs-hybrid/a.js
new file mode 100644
index 00000000000..b02c428e581
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/es6-commonjs-hybrid/a.js
@@ -0,0 +1,3 @@
+const {a, b} = require('./b');
+
+output = a + b;
diff --git a/test/integration/scope-hoisting/commonjs/es6-commonjs-hybrid/b.js b/test/integration/scope-hoisting/commonjs/es6-commonjs-hybrid/b.js
new file mode 100644
index 00000000000..00f2b7f6129
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/es6-commonjs-hybrid/b.js
@@ -0,0 +1,2 @@
+export var a = 2;
+exports.b = 3;
\ No newline at end of file
diff --git a/test/integration/scope-hoisting/commonjs/export-order/a.js b/test/integration/scope-hoisting/commonjs/export-order/a.js
new file mode 100644
index 00000000000..b02c428e581
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/export-order/a.js
@@ -0,0 +1,3 @@
+const {a, b} = require('./b');
+
+output = a + b;
diff --git a/test/integration/scope-hoisting/commonjs/export-order/b.js b/test/integration/scope-hoisting/commonjs/export-order/b.js
new file mode 100644
index 00000000000..f05c9c574ed
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/export-order/b.js
@@ -0,0 +1,2 @@
+exports.a = 2;
+export var b = 3;
diff --git a/test/integration/scope-hoisting/commonjs/import-namespace/a.js b/test/integration/scope-hoisting/commonjs/import-namespace/a.js
new file mode 100644
index 00000000000..40fb3bc0a00
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/import-namespace/a.js
@@ -0,0 +1,3 @@
+import * as test from './b';
+
+output = test.foo;
diff --git a/test/integration/scope-hoisting/commonjs/import-namespace/b.js b/test/integration/scope-hoisting/commonjs/import-namespace/b.js
new file mode 100644
index 00000000000..ea0063ffb86
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/import-namespace/b.js
@@ -0,0 +1 @@
+exports.foo = 2;
diff --git a/test/integration/scope-hoisting/commonjs/live-bindings/a.js b/test/integration/scope-hoisting/commonjs/live-bindings/a.js
new file mode 100644
index 00000000000..44553148d3d
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/live-bindings/a.js
@@ -0,0 +1,5 @@
+const b = require('./b');
+
+b.changeFoo(3);
+
+output = b.default + b.foo + b.bar;
diff --git a/test/integration/scope-hoisting/commonjs/live-bindings/b.js b/test/integration/scope-hoisting/commonjs/live-bindings/b.js
new file mode 100644
index 00000000000..5b2892845f0
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/live-bindings/b.js
@@ -0,0 +1,7 @@
+var foo = 2;
+export default foo;
+export {foo, foo as bar};
+
+export function changeFoo(v) {
+  foo = v;
+}
diff --git a/test/integration/scope-hoisting/commonjs/module-object/a.js b/test/integration/scope-hoisting/commonjs/module-object/a.js
new file mode 100644
index 00000000000..8e7e26c9669
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/module-object/a.js
@@ -0,0 +1,8 @@
+output = {
+  id: module.id,
+  hot: module.hot,
+  type: typeof module,
+  exports: exports,
+  exportsType: typeof exports,
+  require: typeof require
+};
diff --git a/test/integration/scope-hoisting/commonjs/module-object/package.json b/test/integration/scope-hoisting/commonjs/module-object/package.json
new file mode 100644
index 00000000000..e74061aadac
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/module-object/package.json
@@ -0,0 +1,3 @@
+{
+  "browserslist": ["last 1 Chrome versions"]
+}
diff --git a/test/integration/scope-hoisting/commonjs/multi-assign/a.js b/test/integration/scope-hoisting/commonjs/multi-assign/a.js
new file mode 100644
index 00000000000..b9a1d257a12
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/multi-assign/a.js
@@ -0,0 +1,2 @@
+var foo = exports.foo = exports.baz = 2;
+exports.bar = foo;
diff --git a/test/integration/scope-hoisting/commonjs/named-import/a.js b/test/integration/scope-hoisting/commonjs/named-import/a.js
new file mode 100644
index 00000000000..229761a608f
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/named-import/a.js
@@ -0,0 +1,3 @@
+import {foo} from './b';
+
+output = foo;
diff --git a/test/integration/scope-hoisting/commonjs/named-import/b.js b/test/integration/scope-hoisting/commonjs/named-import/b.js
new file mode 100644
index 00000000000..ea0063ffb86
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/named-import/b.js
@@ -0,0 +1 @@
+exports.foo = 2;
diff --git a/test/integration/scope-hoisting/commonjs/object-pattern/a.js b/test/integration/scope-hoisting/commonjs/object-pattern/a.js
new file mode 100644
index 00000000000..51061ef5c68
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/object-pattern/a.js
@@ -0,0 +1,2 @@
+var {foo, bar} = require('./b');
+output = foo + bar;
diff --git a/test/integration/scope-hoisting/commonjs/object-pattern/b.js b/test/integration/scope-hoisting/commonjs/object-pattern/b.js
new file mode 100644
index 00000000000..cc153322e3c
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/object-pattern/b.js
@@ -0,0 +1,2 @@
+exports.foo = 2;
+exports.bar = 3;
diff --git a/test/integration/scope-hoisting/commonjs/object-pattern/package.json b/test/integration/scope-hoisting/commonjs/object-pattern/package.json
new file mode 100644
index 00000000000..b163a7ca22f
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/object-pattern/package.json
@@ -0,0 +1,4 @@
+{
+  "name": "object-pattern",
+  "browserslist": ["last 1 Chrome version"]
+}
diff --git a/test/integration/scope-hoisting/commonjs/re-export-var/a.js b/test/integration/scope-hoisting/commonjs/re-export-var/a.js
new file mode 100644
index 00000000000..39320ab8475
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/re-export-var/a.js
@@ -0,0 +1,3 @@
+const {foo, bar} = require('./b');
+
+output = foo() + bar()
diff --git a/test/integration/scope-hoisting/commonjs/re-export-var/b.js b/test/integration/scope-hoisting/commonjs/re-export-var/b.js
new file mode 100644
index 00000000000..3ebf0b95a1f
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/re-export-var/b.js
@@ -0,0 +1,3 @@
+import {foo, bar} from './c'
+
+export {foo, bar}
diff --git a/test/integration/scope-hoisting/commonjs/re-export-var/c.js b/test/integration/scope-hoisting/commonjs/re-export-var/c.js
new file mode 100644
index 00000000000..b2c661e0ce3
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/re-export-var/c.js
@@ -0,0 +1,7 @@
+const foo = () => 'foo'
+
+function bar() {
+    return 'bar'
+}
+
+export {foo, bar}
diff --git a/test/integration/scope-hoisting/commonjs/require-circular/a.js b/test/integration/scope-hoisting/commonjs/require-circular/a.js
new file mode 100644
index 00000000000..5cb4a5df1e6
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-circular/a.js
@@ -0,0 +1,2 @@
+module.exports.foo = 'foo'
+module.exports = require('./b');
diff --git a/test/integration/scope-hoisting/commonjs/require-circular/b.js b/test/integration/scope-hoisting/commonjs/require-circular/b.js
new file mode 100644
index 00000000000..f4379bfe99b
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-circular/b.js
@@ -0,0 +1 @@
+module.exports = require('./a').foo + ' bar'
diff --git a/test/integration/scope-hoisting/commonjs/require-conditional/a.js b/test/integration/scope-hoisting/commonjs/require-conditional/a.js
new file mode 100644
index 00000000000..8d718b012c9
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-conditional/a.js
@@ -0,0 +1,7 @@
+output('a');
+
+if (b) {
+  require('./b');
+}
+
+output('d');
diff --git a/test/integration/scope-hoisting/commonjs/require-conditional/b.js b/test/integration/scope-hoisting/commonjs/require-conditional/b.js
new file mode 100644
index 00000000000..53356f68b58
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-conditional/b.js
@@ -0,0 +1,2 @@
+output('b');
+require('./c');
diff --git a/test/integration/scope-hoisting/commonjs/require-conditional/c.js b/test/integration/scope-hoisting/commonjs/require-conditional/c.js
new file mode 100644
index 00000000000..e8fcad54935
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-conditional/c.js
@@ -0,0 +1 @@
+output('c');
diff --git a/test/integration/scope-hoisting/commonjs/require-default-export-declaration/a.js b/test/integration/scope-hoisting/commonjs/require-default-export-declaration/a.js
new file mode 100644
index 00000000000..3b74d7866f5
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-default-export-declaration/a.js
@@ -0,0 +1,3 @@
+const foo = require('./b').default;
+
+output = foo();
diff --git a/test/integration/scope-hoisting/commonjs/require-default-export-declaration/b.js b/test/integration/scope-hoisting/commonjs/require-default-export-declaration/b.js
new file mode 100644
index 00000000000..f99965aae75
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-default-export-declaration/b.js
@@ -0,0 +1,3 @@
+export default function foo() {
+  return 2;
+}
diff --git a/test/integration/scope-hoisting/commonjs/require-default-export-expression/a.js b/test/integration/scope-hoisting/commonjs/require-default-export-expression/a.js
new file mode 100644
index 00000000000..92ac4c99872
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-default-export-expression/a.js
@@ -0,0 +1,3 @@
+const foo = require('./b').default;
+
+output = foo;
diff --git a/test/integration/scope-hoisting/commonjs/require-default-export-expression/b.js b/test/integration/scope-hoisting/commonjs/require-default-export-expression/b.js
new file mode 100644
index 00000000000..842e368a0a2
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-default-export-expression/b.js
@@ -0,0 +1 @@
+export default 2;
diff --git a/test/integration/scope-hoisting/commonjs/require-default-export-variable/a.js b/test/integration/scope-hoisting/commonjs/require-default-export-variable/a.js
new file mode 100644
index 00000000000..92ac4c99872
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-default-export-variable/a.js
@@ -0,0 +1,3 @@
+const foo = require('./b').default;
+
+output = foo;
diff --git a/test/integration/scope-hoisting/commonjs/require-default-export-variable/b.js b/test/integration/scope-hoisting/commonjs/require-default-export-variable/b.js
new file mode 100644
index 00000000000..00109805e6d
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-default-export-variable/b.js
@@ -0,0 +1,2 @@
+var foo = 2;
+export default foo;
diff --git a/test/integration/scope-hoisting/commonjs/require-execution-order/a.js b/test/integration/scope-hoisting/commonjs/require-execution-order/a.js
new file mode 100644
index 00000000000..e7ac237460e
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-execution-order/a.js
@@ -0,0 +1,3 @@
+output('a');
+require('./b');
+output('d');
\ No newline at end of file
diff --git a/test/integration/scope-hoisting/commonjs/require-execution-order/b.js b/test/integration/scope-hoisting/commonjs/require-execution-order/b.js
new file mode 100644
index 00000000000..53356f68b58
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-execution-order/b.js
@@ -0,0 +1,2 @@
+output('b');
+require('./c');
diff --git a/test/integration/scope-hoisting/commonjs/require-execution-order/c.js b/test/integration/scope-hoisting/commonjs/require-execution-order/c.js
new file mode 100644
index 00000000000..e8fcad54935
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-execution-order/c.js
@@ -0,0 +1 @@
+output('c');
diff --git a/test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/a.js b/test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/a.js
new file mode 100644
index 00000000000..c9cd1193019
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/a.js
@@ -0,0 +1,8 @@
+output('a');
+
+function x() {
+  return require('./b');
+}
+
+output('d');
+x();
diff --git a/test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/b.js b/test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/b.js
new file mode 100644
index 00000000000..c66532a2b7d
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/b.js
@@ -0,0 +1,2 @@
+output('b');
+import './c';
diff --git a/test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/c.js b/test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/c.js
new file mode 100644
index 00000000000..e8fcad54935
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-in-function-import-hoist/c.js
@@ -0,0 +1 @@
+output('c');
diff --git a/test/integration/scope-hoisting/commonjs/require-in-function-import/a.js b/test/integration/scope-hoisting/commonjs/require-in-function-import/a.js
new file mode 100644
index 00000000000..c9cd1193019
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-in-function-import/a.js
@@ -0,0 +1,8 @@
+output('a');
+
+function x() {
+  return require('./b');
+}
+
+output('d');
+x();
diff --git a/test/integration/scope-hoisting/commonjs/require-in-function-import/b.js b/test/integration/scope-hoisting/commonjs/require-in-function-import/b.js
new file mode 100644
index 00000000000..c579b5b2362
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-in-function-import/b.js
@@ -0,0 +1,2 @@
+import './c';
+output('b');
diff --git a/test/integration/scope-hoisting/commonjs/require-in-function-import/c.js b/test/integration/scope-hoisting/commonjs/require-in-function-import/c.js
new file mode 100644
index 00000000000..e8fcad54935
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-in-function-import/c.js
@@ -0,0 +1 @@
+output('c');
diff --git a/test/integration/scope-hoisting/commonjs/require-in-function-reexport/a.js b/test/integration/scope-hoisting/commonjs/require-in-function-reexport/a.js
new file mode 100644
index 00000000000..c9cd1193019
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-in-function-reexport/a.js
@@ -0,0 +1,8 @@
+output('a');
+
+function x() {
+  return require('./b');
+}
+
+output('d');
+x();
diff --git a/test/integration/scope-hoisting/commonjs/require-in-function-reexport/b.js b/test/integration/scope-hoisting/commonjs/require-in-function-reexport/b.js
new file mode 100644
index 00000000000..cb1902b3f95
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-in-function-reexport/b.js
@@ -0,0 +1,2 @@
+export {x} from './c';
+output('b');
diff --git a/test/integration/scope-hoisting/commonjs/require-in-function-reexport/c.js b/test/integration/scope-hoisting/commonjs/require-in-function-reexport/c.js
new file mode 100644
index 00000000000..a458cb364f0
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-in-function-reexport/c.js
@@ -0,0 +1,2 @@
+export var x = 2;
+output('c');
diff --git a/test/integration/scope-hoisting/commonjs/require-in-function/a.js b/test/integration/scope-hoisting/commonjs/require-in-function/a.js
new file mode 100644
index 00000000000..cba68fdf175
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-in-function/a.js
@@ -0,0 +1,8 @@
+output('a');
+
+function x() {
+  return require('./b');
+}
+
+output('c');
+x();
diff --git a/test/integration/scope-hoisting/commonjs/require-in-function/b.js b/test/integration/scope-hoisting/commonjs/require-in-function/b.js
new file mode 100644
index 00000000000..275c9f1bddd
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-in-function/b.js
@@ -0,0 +1,2 @@
+output('b');
+
diff --git a/test/integration/scope-hoisting/commonjs/require-named-export-declaration/a.js b/test/integration/scope-hoisting/commonjs/require-named-export-declaration/a.js
new file mode 100644
index 00000000000..821bed59980
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-named-export-declaration/a.js
@@ -0,0 +1,3 @@
+const {foo} = require('./b');
+
+output = foo;
diff --git a/test/integration/scope-hoisting/commonjs/require-named-export-declaration/b.js b/test/integration/scope-hoisting/commonjs/require-named-export-declaration/b.js
new file mode 100644
index 00000000000..2263b5a27c2
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-named-export-declaration/b.js
@@ -0,0 +1 @@
+export var foo = 2;
diff --git a/test/integration/scope-hoisting/commonjs/require-named-export-variable/a.js b/test/integration/scope-hoisting/commonjs/require-named-export-variable/a.js
new file mode 100644
index 00000000000..821bed59980
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-named-export-variable/a.js
@@ -0,0 +1,3 @@
+const {foo} = require('./b');
+
+output = foo;
diff --git a/test/integration/scope-hoisting/commonjs/require-named-export-variable/b.js b/test/integration/scope-hoisting/commonjs/require-named-export-variable/b.js
new file mode 100644
index 00000000000..f9d330af7a5
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-named-export-variable/b.js
@@ -0,0 +1,2 @@
+var foo = 2;
+export {foo};
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-all/a.js b/test/integration/scope-hoisting/commonjs/require-re-export-all/a.js
new file mode 100644
index 00000000000..558f70fe546
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-all/a.js
@@ -0,0 +1,3 @@
+const {foo, bar, baz} = require('./b');
+
+output = foo + bar + baz;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-all/b.js b/test/integration/scope-hoisting/commonjs/require-re-export-all/b.js
new file mode 100644
index 00000000000..b60063c4f40
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-all/b.js
@@ -0,0 +1,2 @@
+export * from './c';
+export var baz = 1;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-all/c.js b/test/integration/scope-hoisting/commonjs/require-re-export-all/c.js
new file mode 100644
index 00000000000..d6a7a6a3e60
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-all/c.js
@@ -0,0 +1 @@
+export var foo = 2, bar = 3;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-default/a.js b/test/integration/scope-hoisting/commonjs/require-re-export-default/a.js
new file mode 100644
index 00000000000..ccc03bcb999
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-default/a.js
@@ -0,0 +1,3 @@
+const {foo, baz} = require('./b');
+
+output = foo + baz;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-default/b.js b/test/integration/scope-hoisting/commonjs/require-re-export-default/b.js
new file mode 100644
index 00000000000..7b678240251
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-default/b.js
@@ -0,0 +1,2 @@
+export {default as foo} from './c';
+export var baz = 1;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-default/c.js b/test/integration/scope-hoisting/commonjs/require-re-export-default/c.js
new file mode 100644
index 00000000000..842e368a0a2
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-default/c.js
@@ -0,0 +1 @@
+export default 2;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/a.js b/test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/a.js
new file mode 100644
index 00000000000..a74ec1e77cc
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/a.js
@@ -0,0 +1 @@
+output = require('./b');
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/b.js b/test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/b.js
new file mode 100644
index 00000000000..34a28aa08d0
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/b.js
@@ -0,0 +1 @@
+export * from './c';
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/c.js b/test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/c.js
new file mode 100644
index 00000000000..e1e7cfb81e0
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-exclude-default/c.js
@@ -0,0 +1,2 @@
+export default 2;
+export var foo = 3;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-multiple/a.js b/test/integration/scope-hoisting/commonjs/require-re-export-multiple/a.js
new file mode 100644
index 00000000000..4e65a39e476
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-multiple/a.js
@@ -0,0 +1,3 @@
+const {foo, bar, baz, d} = require('./b');
+
+output = foo + bar + baz + d;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-multiple/b.js b/test/integration/scope-hoisting/commonjs/require-re-export-multiple/b.js
new file mode 100644
index 00000000000..b60063c4f40
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-multiple/b.js
@@ -0,0 +1,2 @@
+export * from './c';
+export var baz = 1;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-multiple/c.js b/test/integration/scope-hoisting/commonjs/require-re-export-multiple/c.js
new file mode 100644
index 00000000000..e749b06020a
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-multiple/c.js
@@ -0,0 +1,2 @@
+export var foo = 2, bar = 3;
+export * from './d';
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-multiple/d.js b/test/integration/scope-hoisting/commonjs/require-re-export-multiple/d.js
new file mode 100644
index 00000000000..cc3b2daa00e
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-multiple/d.js
@@ -0,0 +1 @@
+export var d = 1;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-named/a.js b/test/integration/scope-hoisting/commonjs/require-re-export-named/a.js
new file mode 100644
index 00000000000..ccc03bcb999
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-named/a.js
@@ -0,0 +1,3 @@
+const {foo, baz} = require('./b');
+
+output = foo + baz;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-named/b.js b/test/integration/scope-hoisting/commonjs/require-re-export-named/b.js
new file mode 100644
index 00000000000..8a4642a5883
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-named/b.js
@@ -0,0 +1,2 @@
+export {foo} from './c';
+export var baz = 1;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-named/c.js b/test/integration/scope-hoisting/commonjs/require-re-export-named/c.js
new file mode 100644
index 00000000000..d6a7a6a3e60
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-named/c.js
@@ -0,0 +1 @@
+export var foo = 2, bar = 3;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-namespace/a.js b/test/integration/scope-hoisting/commonjs/require-re-export-namespace/a.js
new file mode 100644
index 00000000000..3fc48702c71
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-namespace/a.js
@@ -0,0 +1,3 @@
+const {c, baz} = require('./b');
+
+output = c.foo + c.bar + baz;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-namespace/b.js b/test/integration/scope-hoisting/commonjs/require-re-export-namespace/b.js
new file mode 100644
index 00000000000..43f5aa737b8
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-namespace/b.js
@@ -0,0 +1,4 @@
+import * as c from './c';
+
+export {c};
+export var baz = 1;
diff --git a/test/integration/scope-hoisting/commonjs/require-re-export-namespace/c.js b/test/integration/scope-hoisting/commonjs/require-re-export-namespace/c.js
new file mode 100644
index 00000000000..d6a7a6a3e60
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-re-export-namespace/c.js
@@ -0,0 +1 @@
+export var foo = 2, bar = 3;
diff --git a/test/integration/scope-hoisting/commonjs/require-renamed-export/a.js b/test/integration/scope-hoisting/commonjs/require-renamed-export/a.js
new file mode 100644
index 00000000000..821bed59980
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-renamed-export/a.js
@@ -0,0 +1,3 @@
+const {foo} = require('./b');
+
+output = foo;
diff --git a/test/integration/scope-hoisting/commonjs/require-renamed-export/b.js b/test/integration/scope-hoisting/commonjs/require-renamed-export/b.js
new file mode 100644
index 00000000000..bfe56e11c81
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-renamed-export/b.js
@@ -0,0 +1,2 @@
+var bar = 2;
+export {bar as foo};
diff --git a/test/integration/scope-hoisting/commonjs/require-resolve/a.js b/test/integration/scope-hoisting/commonjs/require-resolve/a.js
new file mode 100644
index 00000000000..b5f996a1811
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-resolve/a.js
@@ -0,0 +1,3 @@
+const foo = require('./b');
+
+output = require.resolve('./b');
diff --git a/test/integration/scope-hoisting/commonjs/require-resolve/b.js b/test/integration/scope-hoisting/commonjs/require-resolve/b.js
new file mode 100644
index 00000000000..4bbffde1044
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require-resolve/b.js
@@ -0,0 +1 @@
+module.exports = 2;
diff --git a/test/integration/scope-hoisting/commonjs/require/a.js b/test/integration/scope-hoisting/commonjs/require/a.js
new file mode 100644
index 00000000000..de2c5da4b3b
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require/a.js
@@ -0,0 +1,3 @@
+const foo = require('./b');
+
+output = foo;
diff --git a/test/integration/scope-hoisting/commonjs/require/b.js b/test/integration/scope-hoisting/commonjs/require/b.js
new file mode 100644
index 00000000000..4bbffde1044
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/require/b.js
@@ -0,0 +1 @@
+module.exports = 2;
diff --git a/test/integration/scope-hoisting/commonjs/stream-module/a.js b/test/integration/scope-hoisting/commonjs/stream-module/a.js
new file mode 100644
index 00000000000..ce2ad5b6ee5
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/stream-module/a.js
@@ -0,0 +1 @@
+module.exports = require('stream');
diff --git a/test/integration/scope-hoisting/commonjs/this-reference-wrapped/a.js b/test/integration/scope-hoisting/commonjs/this-reference-wrapped/a.js
new file mode 100644
index 00000000000..fa0aaf7fadf
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/this-reference-wrapped/a.js
@@ -0,0 +1,3 @@
+const b = require('./b');
+
+output = b.foo + b.bar;
diff --git a/test/integration/scope-hoisting/commonjs/this-reference-wrapped/b.js b/test/integration/scope-hoisting/commonjs/this-reference-wrapped/b.js
new file mode 100644
index 00000000000..9740b8e6158
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/this-reference-wrapped/b.js
@@ -0,0 +1,2 @@
+this.foo = 2;
+eval('this.bar = 4');
diff --git a/test/integration/scope-hoisting/commonjs/this-reference/a.js b/test/integration/scope-hoisting/commonjs/this-reference/a.js
new file mode 100644
index 00000000000..afb22d072f4
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/this-reference/a.js
@@ -0,0 +1,3 @@
+const b = require('./b');
+
+output = b.foo;
diff --git a/test/integration/scope-hoisting/commonjs/this-reference/b.js b/test/integration/scope-hoisting/commonjs/this-reference/b.js
new file mode 100644
index 00000000000..559a5bfbffb
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/this-reference/b.js
@@ -0,0 +1 @@
+this.foo = 2;
diff --git a/test/integration/scope-hoisting/commonjs/tree-shaking/a.js b/test/integration/scope-hoisting/commonjs/tree-shaking/a.js
new file mode 100644
index 00000000000..2e209e55fd4
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/tree-shaking/a.js
@@ -0,0 +1 @@
+module.exports = require('./b').foo;
diff --git a/test/integration/scope-hoisting/commonjs/tree-shaking/b.js b/test/integration/scope-hoisting/commonjs/tree-shaking/b.js
new file mode 100644
index 00000000000..cc153322e3c
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/tree-shaking/b.js
@@ -0,0 +1,2 @@
+exports.foo = 2;
+exports.bar = 3;
diff --git a/test/integration/scope-hoisting/commonjs/wrap-eval/a.js b/test/integration/scope-hoisting/commonjs/wrap-eval/a.js
new file mode 100644
index 00000000000..de2c5da4b3b
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/wrap-eval/a.js
@@ -0,0 +1,3 @@
+const foo = require('./b');
+
+output = foo;
diff --git a/test/integration/scope-hoisting/commonjs/wrap-eval/b.js b/test/integration/scope-hoisting/commonjs/wrap-eval/b.js
new file mode 100644
index 00000000000..ea0d3a0f6d8
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/wrap-eval/b.js
@@ -0,0 +1,2 @@
+module.exports = 2;
+eval('module.exports = 4');
diff --git a/test/integration/scope-hoisting/commonjs/wrap-module-computed/a.js b/test/integration/scope-hoisting/commonjs/wrap-module-computed/a.js
new file mode 100644
index 00000000000..2b810bb628b
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/wrap-module-computed/a.js
@@ -0,0 +1,2 @@
+exports.foo = 2;
+output = module['exports'];
diff --git a/test/integration/scope-hoisting/commonjs/wrap-module/a.js b/test/integration/scope-hoisting/commonjs/wrap-module/a.js
new file mode 100644
index 00000000000..b7c1511cda1
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/wrap-module/a.js
@@ -0,0 +1,2 @@
+exports.foo = 2;
+output = module;
diff --git a/test/integration/scope-hoisting/commonjs/wrap-return/a.js b/test/integration/scope-hoisting/commonjs/wrap-return/a.js
new file mode 100644
index 00000000000..de2c5da4b3b
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/wrap-return/a.js
@@ -0,0 +1,3 @@
+const foo = require('./b');
+
+output = foo;
diff --git a/test/integration/scope-hoisting/commonjs/wrap-return/b.js b/test/integration/scope-hoisting/commonjs/wrap-return/b.js
new file mode 100644
index 00000000000..7716398359a
--- /dev/null
+++ b/test/integration/scope-hoisting/commonjs/wrap-return/b.js
@@ -0,0 +1,3 @@
+module.exports = 2;
+return;
+module.exports = 4;
diff --git a/test/integration/scope-hoisting/es6/default-export-anonymous/a.js b/test/integration/scope-hoisting/es6/default-export-anonymous/a.js
new file mode 100644
index 00000000000..b37150cd87b
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/default-export-anonymous/a.js
@@ -0,0 +1,3 @@
+import foo from './b';
+
+output = foo();
diff --git a/test/integration/scope-hoisting/es6/default-export-anonymous/b.js b/test/integration/scope-hoisting/es6/default-export-anonymous/b.js
new file mode 100644
index 00000000000..e99e4f2be8d
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/default-export-anonymous/b.js
@@ -0,0 +1,3 @@
+export default function() {
+  return 2;
+}
diff --git a/test/integration/scope-hoisting/es6/default-export-declaration/a.js b/test/integration/scope-hoisting/es6/default-export-declaration/a.js
new file mode 100644
index 00000000000..b37150cd87b
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/default-export-declaration/a.js
@@ -0,0 +1,3 @@
+import foo from './b';
+
+output = foo();
diff --git a/test/integration/scope-hoisting/es6/default-export-declaration/b.js b/test/integration/scope-hoisting/es6/default-export-declaration/b.js
new file mode 100644
index 00000000000..f99965aae75
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/default-export-declaration/b.js
@@ -0,0 +1,3 @@
+export default function foo() {
+  return 2;
+}
diff --git a/test/integration/scope-hoisting/es6/default-export-expression/a.js b/test/integration/scope-hoisting/es6/default-export-expression/a.js
new file mode 100644
index 00000000000..0b1fbc04f48
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/default-export-expression/a.js
@@ -0,0 +1,3 @@
+import foo from './b';
+
+output = foo;
diff --git a/test/integration/scope-hoisting/es6/default-export-expression/b.js b/test/integration/scope-hoisting/es6/default-export-expression/b.js
new file mode 100644
index 00000000000..842e368a0a2
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/default-export-expression/b.js
@@ -0,0 +1 @@
+export default 2;
diff --git a/test/integration/scope-hoisting/es6/default-export-variable/a.js b/test/integration/scope-hoisting/es6/default-export-variable/a.js
new file mode 100644
index 00000000000..0b1fbc04f48
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/default-export-variable/a.js
@@ -0,0 +1,3 @@
+import foo from './b';
+
+output = foo;
diff --git a/test/integration/scope-hoisting/es6/default-export-variable/b.js b/test/integration/scope-hoisting/es6/default-export-variable/b.js
new file mode 100644
index 00000000000..00109805e6d
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/default-export-variable/b.js
@@ -0,0 +1,2 @@
+var foo = 2;
+export default foo;
diff --git a/test/integration/scope-hoisting/es6/dynamic-default-interop/a.js b/test/integration/scope-hoisting/es6/dynamic-default-interop/a.js
new file mode 100644
index 00000000000..dfe67a90274
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/dynamic-default-interop/a.js
@@ -0,0 +1,3 @@
+import shared from './shared';
+
+module.exports = import('./b').then(b => b.out + shared);
diff --git a/test/integration/scope-hoisting/es6/dynamic-default-interop/b.js b/test/integration/scope-hoisting/es6/dynamic-default-interop/b.js
new file mode 100644
index 00000000000..ac5b547154c
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/dynamic-default-interop/b.js
@@ -0,0 +1,3 @@
+import shared from './shared';
+
+export var out = 2 + shared;
diff --git a/test/integration/scope-hoisting/es6/dynamic-default-interop/shared.js b/test/integration/scope-hoisting/es6/dynamic-default-interop/shared.js
new file mode 100644
index 00000000000..4bbffde1044
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/dynamic-default-interop/shared.js
@@ -0,0 +1 @@
+module.exports = 2;
diff --git a/test/integration/scope-hoisting/es6/dynamic-import/a.js b/test/integration/scope-hoisting/es6/dynamic-import/a.js
new file mode 100644
index 00000000000..a8038e64f53
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/dynamic-import/a.js
@@ -0,0 +1,7 @@
+import {compute} from './c'
+
+var b = import('./b');
+
+export default b.then(function ({foo, bar}) {
+  return compute(foo, 0) + compute(bar, 0);
+});
diff --git a/test/integration/scope-hoisting/es6/dynamic-import/b.js b/test/integration/scope-hoisting/es6/dynamic-import/b.js
new file mode 100644
index 00000000000..b5350fa6686
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/dynamic-import/b.js
@@ -0,0 +1,4 @@
+import {compute} from './c'
+
+export var foo = compute(2, 1);
+export var bar = compute(3, 1);
diff --git a/test/integration/scope-hoisting/es6/dynamic-import/c.js b/test/integration/scope-hoisting/es6/dynamic-import/c.js
new file mode 100644
index 00000000000..369d7211d62
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/dynamic-import/c.js
@@ -0,0 +1,3 @@
+export function compute(x, q) {
+    return q ? x * 2 : x / 2
+}
diff --git a/test/integration/scope-hoisting/es6/empty-module/a.js b/test/integration/scope-hoisting/es6/empty-module/a.js
new file mode 100644
index 00000000000..46b671f0c4c
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/empty-module/a.js
@@ -0,0 +1,3 @@
+import b from './b';
+
+export {b};
diff --git a/test/integration/scope-hoisting/es6/empty-module/b.js b/test/integration/scope-hoisting/es6/empty-module/b.js
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/test/integration/scope-hoisting/es6/export-binding-identifiers/a.js b/test/integration/scope-hoisting/es6/export-binding-identifiers/a.js
new file mode 100644
index 00000000000..de4ad7b376d
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/export-binding-identifiers/a.js
@@ -0,0 +1,3 @@
+import {test} from './b'
+
+output = test(exports => Object.keys(exports))
diff --git a/test/integration/scope-hoisting/es6/export-binding-identifiers/b.js b/test/integration/scope-hoisting/es6/export-binding-identifiers/b.js
new file mode 100644
index 00000000000..915389c370e
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/export-binding-identifiers/b.js
@@ -0,0 +1,3 @@
+export function test(arg) {
+    return arg(exports)
+}
diff --git a/test/integration/scope-hoisting/es6/import-commonjs-default/a.js b/test/integration/scope-hoisting/es6/import-commonjs-default/a.js
new file mode 100644
index 00000000000..c2ecbdc135e
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/import-commonjs-default/a.js
@@ -0,0 +1,4 @@
+import foo from './wrapped'
+import bar from './exports'
+
+output = foo() + bar()
diff --git a/test/integration/scope-hoisting/es6/import-commonjs-default/exports.js b/test/integration/scope-hoisting/es6/import-commonjs-default/exports.js
new file mode 100644
index 00000000000..9d178e4d54a
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/import-commonjs-default/exports.js
@@ -0,0 +1 @@
+exports = () => 'bar'
diff --git a/test/integration/scope-hoisting/es6/import-commonjs-default/wrapped.js b/test/integration/scope-hoisting/es6/import-commonjs-default/wrapped.js
new file mode 100644
index 00000000000..a785ce7a0b3
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/import-commonjs-default/wrapped.js
@@ -0,0 +1,3 @@
+// triggers wrapping
+eval('void 0')
+module.exports = () => 'foo'
diff --git a/test/integration/scope-hoisting/es6/import-namespace-commonjs/a.js b/test/integration/scope-hoisting/es6/import-namespace-commonjs/a.js
new file mode 100644
index 00000000000..c0a51b86f1a
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/import-namespace-commonjs/a.js
@@ -0,0 +1,6 @@
+import {foo} from './c';
+
+module.exports = import('./b').then(function (b) {
+  return foo + b.foo;
+});
+
diff --git a/test/integration/scope-hoisting/es6/import-namespace-commonjs/b.js b/test/integration/scope-hoisting/es6/import-namespace-commonjs/b.js
new file mode 100644
index 00000000000..451b4eb82e9
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/import-namespace-commonjs/b.js
@@ -0,0 +1,3 @@
+import * as c from './c';
+
+module.exports = c;
diff --git a/test/integration/scope-hoisting/es6/import-namespace-commonjs/c.js b/test/integration/scope-hoisting/es6/import-namespace-commonjs/c.js
new file mode 100644
index 00000000000..ea0063ffb86
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/import-namespace-commonjs/c.js
@@ -0,0 +1 @@
+exports.foo = 2;
diff --git a/test/integration/scope-hoisting/es6/import-namespace/a.js b/test/integration/scope-hoisting/es6/import-namespace/a.js
new file mode 100644
index 00000000000..40fb3bc0a00
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/import-namespace/a.js
@@ -0,0 +1,3 @@
+import * as test from './b';
+
+output = test.foo;
diff --git a/test/integration/scope-hoisting/es6/import-namespace/b.js b/test/integration/scope-hoisting/es6/import-namespace/b.js
new file mode 100644
index 00000000000..2263b5a27c2
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/import-namespace/b.js
@@ -0,0 +1 @@
+export var foo = 2;
diff --git a/test/integration/scope-hoisting/es6/live-bindings/a.js b/test/integration/scope-hoisting/es6/live-bindings/a.js
new file mode 100644
index 00000000000..d3d7c6e6823
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/live-bindings/a.js
@@ -0,0 +1,5 @@
+import b, {foo, bar, changeFoo} from './b';
+
+changeFoo(3);
+
+output = b + foo + bar;
diff --git a/test/integration/scope-hoisting/es6/live-bindings/b.js b/test/integration/scope-hoisting/es6/live-bindings/b.js
new file mode 100644
index 00000000000..5b2892845f0
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/live-bindings/b.js
@@ -0,0 +1,7 @@
+var foo = 2;
+export default foo;
+export {foo, foo as bar};
+
+export function changeFoo(v) {
+  foo = v;
+}
diff --git a/test/integration/scope-hoisting/es6/multi-export/a.js b/test/integration/scope-hoisting/es6/multi-export/a.js
new file mode 100644
index 00000000000..6cd12dd92ae
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/multi-export/a.js
@@ -0,0 +1,3 @@
+import b, {foo, bar} from './b';
+
+output = b + foo + bar;
diff --git a/test/integration/scope-hoisting/es6/multi-export/b.js b/test/integration/scope-hoisting/es6/multi-export/b.js
new file mode 100644
index 00000000000..d553b25d2b7
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/multi-export/b.js
@@ -0,0 +1,3 @@
+var foo = 2;
+export default foo;
+export {foo, foo as bar};
diff --git a/test/integration/scope-hoisting/es6/named-export-declaration/a.js b/test/integration/scope-hoisting/es6/named-export-declaration/a.js
new file mode 100644
index 00000000000..229761a608f
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/named-export-declaration/a.js
@@ -0,0 +1,3 @@
+import {foo} from './b';
+
+output = foo;
diff --git a/test/integration/scope-hoisting/es6/named-export-declaration/b.js b/test/integration/scope-hoisting/es6/named-export-declaration/b.js
new file mode 100644
index 00000000000..2263b5a27c2
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/named-export-declaration/b.js
@@ -0,0 +1 @@
+export var foo = 2;
diff --git a/test/integration/scope-hoisting/es6/named-export-variable/a.js b/test/integration/scope-hoisting/es6/named-export-variable/a.js
new file mode 100644
index 00000000000..229761a608f
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/named-export-variable/a.js
@@ -0,0 +1,3 @@
+import {foo} from './b';
+
+output = foo;
diff --git a/test/integration/scope-hoisting/es6/named-export-variable/b.js b/test/integration/scope-hoisting/es6/named-export-variable/b.js
new file mode 100644
index 00000000000..f9d330af7a5
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/named-export-variable/b.js
@@ -0,0 +1,2 @@
+var foo = 2;
+export {foo};
diff --git a/test/integration/scope-hoisting/es6/re-export-all-multiple/a.js b/test/integration/scope-hoisting/es6/re-export-all-multiple/a.js
new file mode 100644
index 00000000000..b7bf5c90d72
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-all-multiple/a.js
@@ -0,0 +1,3 @@
+import {foo, bar, baz, a, b} from './b';
+
+output = foo + bar + baz + a + b;
diff --git a/test/integration/scope-hoisting/es6/re-export-all-multiple/b.js b/test/integration/scope-hoisting/es6/re-export-all-multiple/b.js
new file mode 100644
index 00000000000..a67001c5d8e
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-all-multiple/b.js
@@ -0,0 +1,3 @@
+export * from './c';
+export * from './d';
+export var baz = 1;
diff --git a/test/integration/scope-hoisting/es6/re-export-all-multiple/c.js b/test/integration/scope-hoisting/es6/re-export-all-multiple/c.js
new file mode 100644
index 00000000000..d6a7a6a3e60
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-all-multiple/c.js
@@ -0,0 +1 @@
+export var foo = 2, bar = 3;
diff --git a/test/integration/scope-hoisting/es6/re-export-all-multiple/d.js b/test/integration/scope-hoisting/es6/re-export-all-multiple/d.js
new file mode 100644
index 00000000000..4a414b5c1ff
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-all-multiple/d.js
@@ -0,0 +1 @@
+export var a = 4, b = 5;
diff --git a/test/integration/scope-hoisting/es6/re-export-all/a.js b/test/integration/scope-hoisting/es6/re-export-all/a.js
new file mode 100644
index 00000000000..603d59a6f90
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-all/a.js
@@ -0,0 +1,3 @@
+import {foo, bar, baz} from './b';
+
+output = foo + bar + baz;
diff --git a/test/integration/scope-hoisting/es6/re-export-all/b.js b/test/integration/scope-hoisting/es6/re-export-all/b.js
new file mode 100644
index 00000000000..b60063c4f40
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-all/b.js
@@ -0,0 +1,2 @@
+export * from './c';
+export var baz = 1;
diff --git a/test/integration/scope-hoisting/es6/re-export-all/c.js b/test/integration/scope-hoisting/es6/re-export-all/c.js
new file mode 100644
index 00000000000..d6a7a6a3e60
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-all/c.js
@@ -0,0 +1 @@
+export var foo = 2, bar = 3;
diff --git a/test/integration/scope-hoisting/es6/re-export-default/a.js b/test/integration/scope-hoisting/es6/re-export-default/a.js
new file mode 100644
index 00000000000..2a5e2f49538
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-default/a.js
@@ -0,0 +1,3 @@
+import {foo, baz} from './b';
+
+output = foo + baz;
diff --git a/test/integration/scope-hoisting/es6/re-export-default/b.js b/test/integration/scope-hoisting/es6/re-export-default/b.js
new file mode 100644
index 00000000000..6c2f9933ca8
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-default/b.js
@@ -0,0 +1,2 @@
+export foo from './c';
+export var baz = 1;
diff --git a/test/integration/scope-hoisting/es6/re-export-default/c.js b/test/integration/scope-hoisting/es6/re-export-default/c.js
new file mode 100644
index 00000000000..842e368a0a2
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-default/c.js
@@ -0,0 +1 @@
+export default 2;
diff --git a/test/integration/scope-hoisting/es6/re-export-exclude-default/a.js b/test/integration/scope-hoisting/es6/re-export-exclude-default/a.js
new file mode 100644
index 00000000000..37ba9a3d1a8
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-exclude-default/a.js
@@ -0,0 +1,3 @@
+import b, {foo} from './b';
+
+output = {b, foo};
diff --git a/test/integration/scope-hoisting/es6/re-export-exclude-default/b.js b/test/integration/scope-hoisting/es6/re-export-exclude-default/b.js
new file mode 100644
index 00000000000..34a28aa08d0
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-exclude-default/b.js
@@ -0,0 +1 @@
+export * from './c';
diff --git a/test/integration/scope-hoisting/es6/re-export-exclude-default/c.js b/test/integration/scope-hoisting/es6/re-export-exclude-default/c.js
new file mode 100644
index 00000000000..e1e7cfb81e0
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-exclude-default/c.js
@@ -0,0 +1,2 @@
+export default 2;
+export var foo = 3;
diff --git a/test/integration/scope-hoisting/es6/re-export-multiple/a.js b/test/integration/scope-hoisting/es6/re-export-multiple/a.js
new file mode 100644
index 00000000000..6154922e1ad
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-multiple/a.js
@@ -0,0 +1,3 @@
+import {foo, bar, baz, d} from './b';
+
+output = foo + bar + baz + d;
diff --git a/test/integration/scope-hoisting/es6/re-export-multiple/b.js b/test/integration/scope-hoisting/es6/re-export-multiple/b.js
new file mode 100644
index 00000000000..b60063c4f40
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-multiple/b.js
@@ -0,0 +1,2 @@
+export * from './c';
+export var baz = 1;
diff --git a/test/integration/scope-hoisting/es6/re-export-multiple/c.js b/test/integration/scope-hoisting/es6/re-export-multiple/c.js
new file mode 100644
index 00000000000..75f71b809cf
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-multiple/c.js
@@ -0,0 +1,2 @@
+export var foo = 2, bar = 3;
+export * from './d'
diff --git a/test/integration/scope-hoisting/es6/re-export-multiple/d.js b/test/integration/scope-hoisting/es6/re-export-multiple/d.js
new file mode 100644
index 00000000000..cc3b2daa00e
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-multiple/d.js
@@ -0,0 +1 @@
+export var d = 1;
diff --git a/test/integration/scope-hoisting/es6/re-export-named/a.js b/test/integration/scope-hoisting/es6/re-export-named/a.js
new file mode 100644
index 00000000000..2a5e2f49538
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-named/a.js
@@ -0,0 +1,3 @@
+import {foo, baz} from './b';
+
+output = foo + baz;
diff --git a/test/integration/scope-hoisting/es6/re-export-named/b.js b/test/integration/scope-hoisting/es6/re-export-named/b.js
new file mode 100644
index 00000000000..8a4642a5883
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-named/b.js
@@ -0,0 +1,2 @@
+export {foo} from './c';
+export var baz = 1;
diff --git a/test/integration/scope-hoisting/es6/re-export-named/c.js b/test/integration/scope-hoisting/es6/re-export-named/c.js
new file mode 100644
index 00000000000..d6a7a6a3e60
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-named/c.js
@@ -0,0 +1 @@
+export var foo = 2, bar = 3;
diff --git a/test/integration/scope-hoisting/es6/re-export-namespace/a.js b/test/integration/scope-hoisting/es6/re-export-namespace/a.js
new file mode 100644
index 00000000000..eefc5013919
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-namespace/a.js
@@ -0,0 +1,3 @@
+import {c, baz} from './b';
+
+output = c.foo + c.bar + baz;
diff --git a/test/integration/scope-hoisting/es6/re-export-namespace/b.js b/test/integration/scope-hoisting/es6/re-export-namespace/b.js
new file mode 100644
index 00000000000..3f1e1af874a
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-namespace/b.js
@@ -0,0 +1,2 @@
+export * as c from './c';
+export var baz = 1;
diff --git a/test/integration/scope-hoisting/es6/re-export-namespace/c.js b/test/integration/scope-hoisting/es6/re-export-namespace/c.js
new file mode 100644
index 00000000000..d6a7a6a3e60
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-namespace/c.js
@@ -0,0 +1 @@
+export var foo = 2, bar = 3;
diff --git a/test/integration/scope-hoisting/es6/re-export-var/a.js b/test/integration/scope-hoisting/es6/re-export-var/a.js
new file mode 100644
index 00000000000..07897a84949
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-var/a.js
@@ -0,0 +1,3 @@
+import {foo, bar} from './b'
+
+output = foo() + bar()
diff --git a/test/integration/scope-hoisting/es6/re-export-var/b.js b/test/integration/scope-hoisting/es6/re-export-var/b.js
new file mode 100644
index 00000000000..3ebf0b95a1f
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-var/b.js
@@ -0,0 +1,3 @@
+import {foo, bar} from './c'
+
+export {foo, bar}
diff --git a/test/integration/scope-hoisting/es6/re-export-var/c.js b/test/integration/scope-hoisting/es6/re-export-var/c.js
new file mode 100644
index 00000000000..b2c661e0ce3
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/re-export-var/c.js
@@ -0,0 +1,7 @@
+const foo = () => 'foo'
+
+function bar() {
+    return 'bar'
+}
+
+export {foo, bar}
diff --git a/test/integration/scope-hoisting/es6/renamed-export/a.js b/test/integration/scope-hoisting/es6/renamed-export/a.js
new file mode 100644
index 00000000000..229761a608f
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/renamed-export/a.js
@@ -0,0 +1,3 @@
+import {foo} from './b';
+
+output = foo;
diff --git a/test/integration/scope-hoisting/es6/renamed-export/b.js b/test/integration/scope-hoisting/es6/renamed-export/b.js
new file mode 100644
index 00000000000..bfe56e11c81
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/renamed-export/b.js
@@ -0,0 +1,2 @@
+var bar = 2;
+export {bar as foo};
diff --git a/test/integration/scope-hoisting/es6/renamed-import/a.js b/test/integration/scope-hoisting/es6/renamed-import/a.js
new file mode 100644
index 00000000000..009fb8df016
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/renamed-import/a.js
@@ -0,0 +1,3 @@
+import {foo as bar} from './b';
+
+output = bar;
diff --git a/test/integration/scope-hoisting/es6/renamed-import/b.js b/test/integration/scope-hoisting/es6/renamed-import/b.js
new file mode 100644
index 00000000000..2263b5a27c2
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/renamed-import/b.js
@@ -0,0 +1 @@
+export var foo = 2;
diff --git a/test/integration/scope-hoisting/es6/side-effects-false/a.js b/test/integration/scope-hoisting/es6/side-effects-false/a.js
new file mode 100644
index 00000000000..d07f8414fae
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/side-effects-false/a.js
@@ -0,0 +1,3 @@
+import {foo} from 'bar';
+
+output = foo(2);
diff --git a/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/bar.js b/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/bar.js
new file mode 100644
index 00000000000..ef2caf98adf
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/bar.js
@@ -0,0 +1,5 @@
+sideEffect();
+
+export default function bar() {
+  return 2;
+}
diff --git a/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/foo.js b/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/foo.js
new file mode 100644
index 00000000000..36b0b344468
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/foo.js
@@ -0,0 +1,3 @@
+export default function foo(a) {
+  return a * a;
+}
diff --git a/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/index.js b/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/index.js
new file mode 100644
index 00000000000..f9e940c9f6a
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/index.js
@@ -0,0 +1,2 @@
+export foo from './foo';
+export bar from './bar';
diff --git a/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/package.json b/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/package.json
new file mode 100644
index 00000000000..1ea9bea7dfa
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/side-effects-false/node_modules/bar/package.json
@@ -0,0 +1,4 @@
+{
+  "name": "bar",
+  "sideEffects": false
+}
diff --git a/test/integration/scope-hoisting/es6/side-effects/a.js b/test/integration/scope-hoisting/es6/side-effects/a.js
new file mode 100644
index 00000000000..d07f8414fae
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/side-effects/a.js
@@ -0,0 +1,3 @@
+import {foo} from 'bar';
+
+output = foo(2);
diff --git a/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/bar.js b/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/bar.js
new file mode 100644
index 00000000000..ef2caf98adf
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/bar.js
@@ -0,0 +1,5 @@
+sideEffect();
+
+export default function bar() {
+  return 2;
+}
diff --git a/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/foo.js b/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/foo.js
new file mode 100644
index 00000000000..36b0b344468
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/foo.js
@@ -0,0 +1,3 @@
+export default function foo(a) {
+  return a * a;
+}
diff --git a/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/index.js b/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/index.js
new file mode 100644
index 00000000000..f9e940c9f6a
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/index.js
@@ -0,0 +1,2 @@
+export foo from './foo';
+export bar from './bar';
diff --git a/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/package.json b/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/package.json
new file mode 100644
index 00000000000..694594cfe31
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/side-effects/node_modules/bar/package.json
@@ -0,0 +1,3 @@
+{
+  "name": "bar"
+}
diff --git a/test/integration/scope-hoisting/es6/tree-shaking/a.js b/test/integration/scope-hoisting/es6/tree-shaking/a.js
new file mode 100644
index 00000000000..0dacd04141e
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/tree-shaking/a.js
@@ -0,0 +1,2 @@
+import {foo} from './b';
+export default foo;
diff --git a/test/integration/scope-hoisting/es6/tree-shaking/b.js b/test/integration/scope-hoisting/es6/tree-shaking/b.js
new file mode 100644
index 00000000000..ad76adb4cfb
--- /dev/null
+++ b/test/integration/scope-hoisting/es6/tree-shaking/b.js
@@ -0,0 +1,2 @@
+export var foo = 2;
+export var bar = 3;
diff --git a/test/integration/sourcemap-reference/data.js b/test/integration/sourcemap-reference/data.js
new file mode 100644
index 00000000000..6417174f874
--- /dev/null
+++ b/test/integration/sourcemap-reference/data.js
@@ -0,0 +1,6 @@
+module.exports = {
+  some: "data",
+  more: {
+    data: "value"
+  }
+};
diff --git a/test/integration/sourcemap-reference/data.json b/test/integration/sourcemap-reference/data.json
deleted file mode 100644
index f18b8ec4913..00000000000
--- a/test/integration/sourcemap-reference/data.json
+++ /dev/null
@@ -1,6 +0,0 @@
-{
-  "some": "data",
-  "more": {
-    "data": "value"
-  }
-}
\ No newline at end of file
diff --git a/test/integration/sourcemap-reference/index.js b/test/integration/sourcemap-reference/index.js
index 298eba3f0a8..f9d744d1297 100644
--- a/test/integration/sourcemap-reference/index.js
+++ b/test/integration/sourcemap-reference/index.js
@@ -1 +1,2 @@
-import './data.json';
\ No newline at end of file
+import data from './data';
+export default data;
diff --git a/test/javascript.js b/test/javascript.js
index 654333aac13..a833efb2d55 100644
--- a/test/javascript.js
+++ b/test/javascript.js
@@ -664,19 +664,29 @@ describe('javascript', function() {
   });
 
   it('should minify YAML for production', async function() {
-    await bundle(__dirname + '/integration/yaml/index.js', {
+    let b = await bundle(__dirname + '/integration/yaml/index.js', {
+      scopeHoist: false,
       production: true
     });
 
+    let output = await run(b);
+    assert.equal(typeof output, 'function');
+    assert.equal(output(), 3);
+
     let json = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
     assert(json.includes('{a:1,b:{c:2}}'));
   });
 
   it('should minify TOML for production', async function() {
-    await bundle(__dirname + '/integration/toml/index.js', {
+    let b = await bundle(__dirname + '/integration/toml/index.js', {
+      scopeHoist: false,
       production: true
     });
 
+    let output = await run(b);
+    assert.equal(typeof output, 'function');
+    assert.equal(output(), 3);
+
     let json = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
     assert(json.includes('{a:1,b:{c:2}}'));
   });
@@ -685,40 +695,40 @@ describe('javascript', function() {
     await bundle(__dirname + '/integration/babel/index.js');
 
     let file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
-    assert(file.includes('class Foo {}'));
-    assert(file.includes('class Bar {}'));
+    assert(!file.includes('function Foo'));
+    assert(!file.includes('function Bar'));
   });
 
   it('should compile with babel with default engines if no config', async function() {
     await bundle(__dirname + '/integration/babel-default/index.js');
 
     let file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
-    assert(!file.includes('class Foo {}'));
-    assert(!file.includes('class Bar {}'));
+    assert(file.includes('function Foo'));
+    assert(file.includes('function Bar'));
   });
 
   it('should support compiling with babel using browserlist', async function() {
     await bundle(__dirname + '/integration/babel-browserslist/index.js');
 
     let file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
-    assert(!file.includes('class Foo {}'));
-    assert(!file.includes('class Bar {}'));
+    assert(file.includes('function Foo'));
+    assert(file.includes('function Bar'));
   });
 
   it('should support splitting babel-polyfill using browserlist', async function() {
     await bundle(__dirname + '/integration/babel-polyfill/index.js');
 
     let file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
-    assert(file.includes('async function Bar() {}'));
+    assert(file.includes('async function'));
     assert(!file.includes('regenerator'));
   });
 
   it('should support compiling with babel using browserslist for different environments', async function() {
     async function testBrowserListMultipleEnv(projectBasePath) {
       // Transpiled destructuring, like r = p.prop1, o = p.prop2, a = p.prop3;
-      const prodRegExp = /\w ?= ?\w\.prop1, ?\w ?= ?\w\.prop2, ?\w ?= ?\w\.prop3;/;
+      const prodRegExp = /\S+ ?= ?\S+\.prop1,\s*?\S+ ?= ?\S+\.prop2,\s*?\S+ ?= ?\S+\.prop3;/;
       // ES6 Destructuring, like in the source;
-      const devRegExp = /const ?{\s*prop1,\s*prop2,\s*prop3\s*} ?= ?.*/;
+      const devRegExp = /const ?{\s*prop1(:.+)?,\s*prop2(:.+)?,\s*prop3(:.+)?\s*} ?= ?.*/;
       let file;
       // Dev build test
       await bundle(__dirname + projectBasePath + '/index.js');
@@ -727,6 +737,7 @@ describe('javascript', function() {
       assert(prodRegExp.test(file) === false);
       // Prod build test
       await bundle(__dirname + projectBasePath + '/index.js', {
+        minify: false,
         production: true
       });
       file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
@@ -746,8 +757,8 @@ describe('javascript', function() {
     await bundle(__dirname + '/integration/babel-node-modules/index.js');
 
     let file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
-    assert(file.includes('class Foo {}'));
-    assert(!file.includes('class Bar {}'));
+    assert(/class \S+ \{\}/.test(file));
+    assert(file.includes('function Bar'));
   });
 
   it('should compile node_modules if legacy browserify options are found', async function() {
@@ -756,8 +767,8 @@ describe('javascript', function() {
     );
 
     let file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
-    assert(!file.includes('class Foo {}'));
-    assert(!file.includes('class Bar {}'));
+    assert(file.includes('function Foo'));
+    assert(file.includes('function Bar'));
   });
 
   it('should compile node_modules with browserslist to app target', async function() {
@@ -766,16 +777,16 @@ describe('javascript', function() {
     );
 
     let file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
-    assert(!file.includes('class Foo {}'));
-    assert(!file.includes('class Bar {}'));
+    assert(file.includes('function Foo'));
+    assert(file.includes('function Bar'));
   });
 
   it('should compile node_modules when symlinked with a source field in package.json', async function() {
     await bundle(__dirname + '/integration/babel-node-modules-source/index.js');
 
     let file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
-    assert(!file.includes('class Foo {}'));
-    assert(!file.includes('class Bar {}'));
+    assert(file.includes('function Foo'));
+    assert(file.includes('function Bar'));
   });
 
   it('should not compile node_modules with a source field in package.json when not symlinked', async function() {
@@ -784,8 +795,8 @@ describe('javascript', function() {
     );
 
     let file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
-    assert(file.includes('class Foo {}'));
-    assert(!file.includes('class Bar {}'));
+    assert(!file.includes('function Foo'));
+    assert(file.includes('function Bar'));
   });
 
   it('should support compiling JSX', async function() {
@@ -933,7 +944,7 @@ describe('javascript', function() {
     };
     mockDefine.amd = true;
 
-    await run(b, {define: mockDefine});
+    await run(b, {define: mockDefine, module: undefined});
     assert.equal(test(), 'Test!');
   });
 
@@ -942,7 +953,7 @@ describe('javascript', function() {
       global: 'testing'
     });
 
-    const ctx = await run(b, null, {require: false});
+    const ctx = await run(b, {module: undefined}, {require: false});
     assert.equal(ctx.window.testing(), 'Test!');
   });
 
@@ -954,7 +965,7 @@ describe('javascript', function() {
     };
     mockDefine.amd = true;
 
-    await run(b, {define: mockDefine});
+    await run(b, {define: mockDefine, module: undefined});
     assert.equal(test, 2);
   });
 });
diff --git a/test/scope-hoisting.js b/test/scope-hoisting.js
new file mode 100644
index 00000000000..a666e9da09a
--- /dev/null
+++ b/test/scope-hoisting.js
@@ -0,0 +1,761 @@
+const assert = require('assert');
+const {bundle: _bundle, run} = require('./utils');
+const fs = require('../src/utils/fs');
+
+const bundle = (name, opts = {}) =>
+  _bundle(name, Object.assign({scopeHoist: true}, opts));
+
+describe('scope hoisting', function() {
+  describe('es6', function() {
+    it('supports default imports and exports of expressions', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/es6/default-export-expression/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports default imports and exports of declarations', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/es6/default-export-declaration/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports default imports and exports of anonymous declarations', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/es6/default-export-anonymous/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports default imports and exports of variables', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/es6/default-export-variable/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports named imports and exports of declarations', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/es6/named-export-declaration/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports named imports and exports of variables', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/named-export-variable/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports renaming imports', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/renamed-import/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports renaming exports', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/renamed-export/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports importing a namespace of exported values', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/import-namespace/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports re-exporting all exports from another module', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/re-export-all/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 6);
+    });
+
+    it('supports re-exporting all exports from multiple modules', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/es6/re-export-all-multiple/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 15);
+    });
+
+    it('supports re-exporting all exports from multiple modules deep', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/re-export-multiple/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 7);
+    });
+
+    it('supports re-exporting individual named exports from another module', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/re-export-named/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 3);
+    });
+
+    it('supports re-exporting default exports from another module', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/re-export-default/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 3);
+    });
+
+    it('supports re-exporting a namespace from another module', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/re-export-namespace/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 6);
+    });
+
+    it('excludes default when re-exporting a module', async function() {
+      let threw = false;
+      try {
+        await bundle(
+          __dirname +
+            '/integration/scope-hoisting/es6/re-export-exclude-default/a.js'
+        );
+      } catch (err) {
+        threw = true;
+        assert.equal(err.message, "b.js does not export 'default'");
+      }
+
+      assert(threw);
+    });
+
+    it('supports multiple exports of the same variable', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/multi-export/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 6);
+    });
+
+    it('supports live bindings of named exports', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/live-bindings/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 8);
+    });
+
+    it('supports dynamic import syntax for code splitting', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/dynamic-import/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(await output.default, 5);
+    });
+
+    it('should not export function arguments', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/es6/export-binding-identifiers/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, ['test']);
+    });
+
+    it('supports import default CommonJS interop', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/es6/import-commonjs-default/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, 'foobar');
+    });
+
+    it('supports import default CommonJS interop with dynamic imports', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/es6/dynamic-default-interop/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(await output, 6);
+    });
+
+    it('supports exporting an import', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/re-export-var/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, 'foobar');
+    });
+
+    it('keeps side effects by default', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/side-effects/a.js'
+      );
+
+      let called = false;
+      let output = await run(b, {
+        sideEffect: () => {
+          called = true;
+        }
+      });
+
+      assert(called, 'side effect not called');
+      assert.deepEqual(output, 4);
+    });
+
+    it('supports the package.json sideEffects: false flag', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/side-effects-false/a.js'
+      );
+
+      let called = false;
+      let output = await run(b, {
+        sideEffect: () => {
+          called = true;
+        }
+      });
+
+      assert(!called, 'side effect called');
+      assert.deepEqual(output, 4);
+    });
+
+    it('missing exports should be replaced with an empty object', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/empty-module/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, {b: {}});
+    });
+
+    it('supports importing a namespace from a commonjs module when code split', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/es6/import-namespace-commonjs/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(await output, 4);
+    });
+
+    it('removes unused exports', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/tree-shaking/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output.default, 2);
+
+      let contents = await fs.readFile(__dirname + '/dist/a.js', 'utf8');
+      assert(contents.includes('foo'));
+      assert(!contents.includes('bar'));
+    });
+  });
+
+  describe('commonjs', function() {
+    it('supports require of commonjs modules', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/require/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports default imports of commonjs modules', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/default-import/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports named imports of commonjs modules', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/named-import/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports namespace imports of commonjs modules', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/import-namespace/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports require of es6 default export of expressions', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-default-export-expression/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports require of es6 default export of declarations', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-default-export-declaration/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports require of es6 default export of variables', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-default-export-variable/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports require of es6 named export of declarations', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-named-export-declaration/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports require of es6 named export of variables', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-named-export-variable/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports require of es6 renamed exports', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-renamed-export/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports require of es6 module re-exporting all exports from another module', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-re-export-all/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 6);
+    });
+
+    it('supports require of es6 module re-exporting all exports from multiple modules', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-re-export-multiple/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 7);
+    });
+
+    it('supports re-exporting individual named exports from another module', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-re-export-named/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 3);
+    });
+
+    it('supports re-exporting default exports from another module', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-re-export-default/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 3);
+    });
+
+    it('supports re-exporting a namespace from another module', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-re-export-namespace/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 6);
+    });
+
+    it('excludes default when re-exporting a module', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-re-export-exclude-default/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, {foo: 3});
+    });
+
+    it('supports hybrid ES6 + commonjs modules', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/es6-commonjs-hybrid/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 5);
+    });
+
+    it('inserts commonjs exports object in the right place', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/export-order/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 5);
+    });
+
+    it('define exports in the outermost scope', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/define-exports/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 'bar');
+    });
+
+    it('supports live bindings of named exports', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/live-bindings/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 8);
+    });
+
+    it('should wrap modules that use eval in a function', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/wrap-eval/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 4);
+    });
+
+    it('should wrap modules that have a top-level return', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/wrap-return/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('should wrap modules that access `module` as a free variable', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/wrap-module/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, {exports: {foo: 2}});
+    });
+
+    it('should wrap modules that non-statically access `module`', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/wrap-module-computed/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, {foo: 2});
+    });
+
+    it('supports assigning to this as exports object', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/this-reference/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 2);
+    });
+
+    it('supports assigning to this as exports object in wrapped module', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/this-reference-wrapped/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 6);
+    });
+
+    it('supports module object properties', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/module-object/a.js'
+      );
+
+      // TODO: this test doesn't currently work in older browsers since babel
+      // replaces the typeof calls before we can get to them.
+      let output = await run(b);
+      assert.equal(output.id, b.entryAsset.id);
+      assert.equal(output.hot, null);
+      assert.equal(output.type, 'object');
+      assert.deepEqual(output.exports, {});
+      assert.equal(output.exportsType, 'object');
+      assert.equal(output.require, 'function');
+    });
+
+    it('supports require.resolve calls', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/require-resolve/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(
+        output,
+        Array.from(b.assets).find(a => a.name.endsWith('b.js')).id
+      );
+    });
+
+    it('supports requiring a re-exported ES6 import', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/re-export-var/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, 'foobar');
+    });
+
+    it('supports object pattern requires', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/object-pattern/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, 5);
+    });
+
+    it('eliminates CommonJS export object where possible', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/eliminate-exports/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, 6);
+    });
+
+    it('supports multiple assignments in one line', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/multi-assign/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, {foo: 2, bar: 2, baz: 2});
+    });
+
+    it('supports circular dependencies', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/require-circular/a.js'
+      );
+
+      let output = await run(b);
+      assert.equal(output, 'foo bar');
+    });
+
+    it('executes modules in the correct order', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-execution-order/a.js'
+      );
+
+      let out = [];
+      await run(b, {
+        output(o) {
+          out.push(o);
+        }
+      });
+
+      assert.deepEqual(out, ['a', 'b', 'c', 'd']);
+    });
+
+    it('supports conditional requires', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-conditional/a.js'
+      );
+
+      let out = [];
+      await run(b, {
+        b: false,
+        output(o) {
+          out.push(o);
+        }
+      });
+
+      assert.deepEqual(out, ['a', 'd']);
+
+      out = [];
+      await run(b, {
+        b: true,
+        output(o) {
+          out.push(o);
+        }
+      });
+
+      assert.deepEqual(out, ['a', 'b', 'c', 'd']);
+    });
+
+    it('supports requires inside functions', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-in-function/a.js'
+      );
+
+      let out = [];
+      await run(b, {
+        output(o) {
+          out.push(o);
+        }
+      });
+
+      assert.deepEqual(out, ['a', 'c', 'b']);
+    });
+
+    it('supports requires inside functions with es6 import side effects', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-in-function-import/a.js'
+      );
+
+      let out = [];
+      await run(b, {
+        output(o) {
+          out.push(o);
+        }
+      });
+
+      assert.deepEqual(out, ['a', 'd', 'c', 'b']);
+    });
+
+    it('hoists import calls to the top', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-in-function-import-hoist/a.js'
+      );
+
+      let out = [];
+      await run(b, {
+        output(o) {
+          out.push(o);
+        }
+      });
+
+      assert.deepEqual(out, ['a', 'd', 'c', 'b']);
+    });
+
+    it('supports requires inside functions with es6 re-export side effects', async function() {
+      let b = await bundle(
+        __dirname +
+          '/integration/scope-hoisting/commonjs/require-in-function-reexport/a.js'
+      );
+
+      let out = [];
+      await run(b, {
+        output(o) {
+          out.push(o);
+        }
+      });
+
+      assert.deepEqual(out, ['a', 'd', 'c', 'b']);
+    });
+
+    it('can bundle the node stream module', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/stream-module/a.js'
+      );
+
+      let res = await run(b);
+      assert.equal(typeof res.Readable, 'function');
+      assert.equal(typeof res.Writable, 'function');
+      assert.equal(typeof res.Duplex, 'function');
+    });
+
+    it('missing exports should be replaced with an empty object', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/empty-module/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, {b: {}});
+    });
+
+    it('removes unused exports', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/commonjs/tree-shaking/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, 2);
+
+      let contents = await fs.readFile(__dirname + '/dist/a.js', 'utf8');
+      assert(contents.includes('foo'));
+      assert(!contents.includes('bar'));
+    });
+  });
+});
diff --git a/test/sourcemaps.js b/test/sourcemaps.js
index f1f6242f495..7544dbfdfdd 100644
--- a/test/sourcemaps.js
+++ b/test/sourcemaps.js
@@ -177,7 +177,7 @@ describe('sourcemaps', function() {
       childBundles: [
         {
           type: 'js',
-          assets: ['index.js', 'data.json'],
+          assets: ['index.js', 'data.js'],
           childBundles: [
             {
               type: 'map'
diff --git a/test/utils.js b/test/utils.js
index b1ff392ec35..a0cd065248a 100644
--- a/test/utils.js
+++ b/test/utils.js
@@ -89,8 +89,11 @@ function prepareBrowserContext(bundle, globals) {
     }
   };
 
+  var exports = {};
   var ctx = Object.assign(
     {
+      exports,
+      module: {exports},
       document: fakeDocument,
       WebSocket,
       console,
@@ -121,6 +124,7 @@ function prepareNodeContext(bundle, globals) {
   var ctx = Object.assign(
     {
       module: mod,
+      exports: module.exports,
       __filename: bundle.name,
       __dirname: path.dirname(bundle.name),
       require: function(path) {
@@ -159,7 +163,14 @@ async function run(bundle, globals, opts = {}) {
   vm.runInContext(await fs.readFile(bundle.name), ctx);
 
   if (opts.require !== false) {
-    return ctx.parcelRequire(bundle.entryAsset.id);
+    if (ctx.parcelRequire) {
+      return ctx.parcelRequire(bundle.entryAsset.id);
+    } else if (ctx.output) {
+      return ctx.output;
+    }
+    if (ctx.module) {
+      return ctx.module.exports;
+    }
   }
 
   return ctx;
diff --git a/test/watcher.js b/test/watcher.js
index 11ad0ec3b85..9b9019034b9 100644
--- a/test/watcher.js
+++ b/test/watcher.js
@@ -235,8 +235,8 @@ describe('watcher', function() {
 
     await b.bundle();
     let file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
-    assert(file.includes('class Foo {}'));
-    assert(file.includes('class Bar {}'));
+    assert(!file.includes('function Foo'));
+    assert(!file.includes('function Bar'));
 
     // Change babelrc, should recompile both files
     let babelrc = JSON.parse(
@@ -250,7 +250,7 @@ describe('watcher', function() {
 
     await nextBundle(b);
     file = await fs.readFile(__dirname + '/dist/index.js', 'utf8');
-    assert(!file.includes('class Foo {}'));
-    assert(!file.includes('class Bar {}'));
+    assert(file.includes('function Foo'));
+    assert(file.includes('function Bar'));
   });
 });