Bundle most packages in Babel 8 #14179

JLHwung · 2022-01-19T17:16:23Z

Q	A
Fixed Issues?	Bundle most packages in Babel 8, fixes #9575
Patch: Bug Fix?
Major: Breaking Change?	Yes, behind `BABEL_8_BREAKING` flag
Minor: New Feature?
Tests Added + Pass?	Yes
Documentation PR Link	babel/website#2765
Any Dependency Changes?
License	MIT

In this PR we bundle most packages when built with BABEL_8_BREAKING with exceptions listed below:

eslint/* packages
@babel/runtime
@babel/runtime-corejs2
@babel/runtime-corejs3
@babel/cli: Rollup hangs due to shebang
@rollup/plugin-node-resolve does not support browser: false when exports are provided in package.json
@babel/register
@babel/core
@babel/plugin-transform-runtime
@babel/helper-fixtures: `@rollup/plugin-commonjs messes up with dynamic require in this package
@babel/helpers: Some fixture tests requires internal lib/helpers access

Notable internal changes:

@babel/traverse:

The virtual-types typings generator has been removed because it needs internal access to transpiled source files, which is not available when we bundle @babel/traverse. Instead the typings are now explicitly listed on packages/babel-traverse/src/path/lib/virtual-types.ts and packages/babel-traverse/src/path/lib/virtual-types-validator.ts.
The virtual types validator are refactored to straightforward notations. Instead of dynamically generating validator interface t["is" + virtualType] = validators[virtualType].checkPath, they are now explicitly declared in packages/babel-traverse/src/path/lib/virtual-types-validator.ts. Now TS manages to detect some bugs in the validators and I have fixed reported issues. And it improves method navigability.

Known issues: I will fix them in a subsequent PR so the Babel-traverse / optional chaining fixes in this PR can be landed to Babel 7 soon.

react-jsx-development depends on exports in react-jsx
corejs-compat/data.json is bundled in preset-env

Because the bundling happens during prepublish phrase, it can only be tested by Babel 8 breaking tests hosted in Circle CI.

babel-bot · 2022-01-19T17:19:09Z

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/52958/

JLHwung · 2022-01-24T21:13:29Z

Gulpfile.mjs

@@ -393,8 +405,33 @@ function buildRollup(packages, targetBrowsers) {
          name,
          sourcemap: sourcemap,
          exports: "named",
+          interop(id) {


The interop config fixes a regression issue: Using @babel/plugin-proposal-optional-chaining with an old @babel/parser version will throw optional chaining syntax is required.

In https://unpkg.com/@babel/plugin-proposal-optional-chaining@7.16.7/lib/index.js,

inherits: syntaxOptionalChaining__default['default'].default,

the inherited syntax plugin is always undefined because we and rollup both apply interop transform on the default exports.

Now it generates

inherits: syntaxOptionalChaining.default,

as expected.

JLHwung · 2022-01-24T22:38:56Z

Gulpfile.mjs

+      }
+      if (pkgJSON === undefined) continue;
+      const src = packageDir + "/" + dir;
+      if (pkgJSON.main) {


We may extend support to pkgJSON.exports in the future. However, bundling a package with multiple exports could be tricky: Do we want to bundle multiple entry thus minimizing internal module imports? Or do we want to bundle modules in topological order thus minimizing the artifact size?

Since few packages supports multiple exports, I think supporting main is good enough.

JLHwung · 2022-01-31T20:02:25Z

The CI error is unrelated, it will be fixed in #14087.

Gulpfile.mjs

liuxingbaoyu · 2022-07-27T19:52:26Z

To be honest, I'm a little concerned that this will affect debugging while in use, hope it's ok.

JLHwung · 2022-07-27T20:04:23Z

Note that make watch calls yarn gulp build-no-bundle, which will skip rollup and run Babel on source files, so this PR does not complicate current contributing workflow. On CI we build with rollup and test against that. Users generally benefit from bundling: less modules yields shorter start-up time.

liuxingbaoyu · 2022-07-27T20:10:35Z

Yeah, I mean when babel is a dependency.
I'm worried this will be a little more difficult. (especially traverse)

PS: I haven't even used make watch because of make, lol😂

liuxingbaoyu · 2022-07-27T20:18:31Z

Also it looks like this PR is done #9575.

liuxingbaoyu · 2022-08-10T08:22:46Z

Gulpfile.mjs

@@ -294,23 +299,49 @@ if (process.env.CIRCLE_PR_NUMBER) {

 const babelVersion =
  require("./packages/babel-core/package.json").version + versionSuffix;
-function buildRollup(packages, targetBrowsers) {
+function buildRollup(packages, buildStandalone) {
  const sourcemap = process.env.NODE_ENV === "production";


Not related to this PR:
Do we need to include source maps in the release?
Currently NODE_ENV is only used in prepublish-build(doesn't even include prepublish-build-standalone), I don't know if this is expected.

(found this when I tried to debug in the repl)

Good catch. I think the source maps should be included, especially for a browser package like babel-standalone.

Co-authored-by: liuxingbaoyu <30521560+liuxingbaoyu@users.noreply.github.com>

JLHwung added the babel-8-dev → main label Jan 19, 2022

JLHwung force-pushed the bundle-most-packages-in-babel-8 branch 3 times, most recently from 5ab46bb to e3aa0e5 Compare January 24, 2022 20:37

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JLHwung marked this pull request as ready for review January 24, 2022 22:30

JLHwung added the PR: Internal 🏠 A type of pull request used for our changelog categories label Jan 24, 2022

JLHwung force-pushed the bundle-most-packages-in-babel-8 branch from 1e618f9 to e9f9361 Compare January 24, 2022 22:32

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JLHwung force-pushed the bundle-most-packages-in-babel-8 branch from e9f9361 to df66712 Compare January 27, 2022 20:49

JLHwung marked this pull request as draft January 27, 2022 21:28

JLHwung force-pushed the bundle-most-packages-in-babel-8 branch from 11e6b20 to 61d987f Compare January 31, 2022 19:34

JLHwung marked this pull request as ready for review January 31, 2022 20:01

JLHwung force-pushed the bundle-most-packages-in-babel-8 branch from 61d987f to f1ac928 Compare February 3, 2022 20:07

JLHwung mentioned this pull request Jul 11, 2022

Prepare for compiling Babel to native ESM #13414

Merged

JLHwung mentioned this pull request Jul 26, 2022

Restructure virtual types validator #14799

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JLHwung force-pushed the bundle-most-packages-in-babel-8 branch 2 times, most recently from 0822478 to 5c6bae9 Compare July 27, 2022 17:16

JLHwung requested review from nicolo-ribaudo and liuxingbaoyu July 27, 2022 17:59

liuxingbaoyu reviewed Jul 27, 2022

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JLHwung and others added 17 commits September 16, 2022 14:45

fix: only minify @babel/standalone

d9ac47e

bundle more packages

906f313

rename preset-env tests requiring internals

b5a20ee

rename helper-compilation-targets test files

84d97a7

rename preset-flow test files

ca41406

disable output.interop for packages not in this repo

96ef63a

expand external to cover subimports

30f8846

add @babel/compat-data sub exports to external

b4be207

do not specify external when building standalone

8d345df

cast BABEL_8_BREAKING to bool

fb0c6ba

do not bundle plugin-transform-react-jsx

813405c

fix linting errors

3de1482

output ESM module when USE_ESM is specified

29fade1

chore: avoid reading @babel/types internals

d34a99d

Update Gulpfile.mjs

c057d84

Co-authored-by: liuxingbaoyu <30521560+liuxingbaoyu@users.noreply.github.com>

Apply suggestions from code review

fe14c1f

Co-authored-by: liuxingbaoyu <30521560+liuxingbaoyu@users.noreply.github.com>

support mjs in rollup node polyfill

a8e086e

nicolo-ribaudo force-pushed the bundle-most-packages-in-babel-8 branch from a090d08 to a8e086e Compare September 16, 2022 06:07

Minor style updates

331d0be

nicolo-ribaudo approved these changes Sep 16, 2022

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nicolo-ribaudo merged commit aad7eb7 into babel:main Sep 16, 2022

nicolo-ribaudo deleted the bundle-most-packages-in-babel-8 branch September 16, 2022 07:49

nicolo-ribaudo removed the PR: Internal 🏠 A type of pull request used for our changelog categories label Sep 16, 2022

github-actions bot added the outdated A closed issue/PR that is archived due to age. Recommended to make a new issue label Jan 3, 2023

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nicolo-ribaudo added babel 8 and removed babel-8-dev → main labels Aug 8, 2023

JLHwung added PR: Breaking Change 💥 A type of pull request used for our changelog categories for next major release and removed babel 8 labels Aug 9, 2023

JLHwung added this to the v8.0.0 milestone Aug 9, 2023

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Bundle most packages in Babel 8 #14179

Bundle most packages in Babel 8 #14179

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Bundle most packages in Babel 8 #14179

Bundle most packages in Babel 8 #14179

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