v6.7.4

Bug Fix

• babel-traverse

  • #3419: Keep the context stack balanced to ensure that contexts are properly popped off. (@loganfsmyth)

    This bug was causing issues internally because the context system relies on the queues being balanced when deciding what nodes need to be re-processed and which do not. When it becomes imbalanced, nodes can be forgotten or skipped, causing issues like https://phabricator.babeljs.io/T7199 which broke ES6 modules on IE8 with the ES3 transforms.

  • #3420: Invalidate the scope cache when nodes are moved. (@loganfsmyth)

    This bug was causing scoping issues in some cases if a node was moved to a new location that was not nested inside a new scope. When this case was hit, the old cached scope would be used, causing issues like https://phabricator.babeljs.io/T7194, https://phabricator.babeljs.io/T6934, and https://phabricator.babeljs.io/T6728.

• babel-runtime
  • #3424: Fix an issue causing runtime breakage on IE8. (@zloirock)
• babel-plugin-transform-react-jsx
  • #3430: Stop the JSX transform from using an AST node in two places. (@amasad)

Misc

• babel-traverse
  • #3432: Fix a spelling mistake in an error message. (@simeonwillbanks)

Internal

• #3400: Fix an issue that could cause a local clone of Babel to error out if the github repo was in a location with a parent .babelrc file. (@callumlocke)
• #3431: Fix an issue that was causing the local-development watcher to occasionally rebuild with the incorrect file content. (@loganfsmyth)
• #3436: Update our linting utility version. (@hzoo)
• #3437: Remove an unused dependency. (@hzoo)
• babel-core
  • #3429: Avoid potential side-effects in a test. (@amasad)

v6.7.2

6.7.2 (2016-03-10)

Flow fix, mention babylon move

Bug Fix

• babel-traverse
  • #3414: Warn on Flow-based bindings and don't count as a const violation. (@amasad)

We are treating static type information as part of the runtime scope information. So a Flow type declaration was being considered a binding on the scope. This was specifically problematic when we thinking that we're overwriting a binding:

The following code:

declare class foo {}
const foo = 1;

Will result in the error: "foo" is read-only

Since removing support for flow-based bindings would be a breaking change, in this release I'm adding a warning whenever someone tries to use Flow types as bindings.

Internal

• babel-code-frame, babel-generator, babel-messages, babel-plugin-undeclared-variables-check, babel-polyfill, babel-register, babel-traverse, babel-types
  • #3410 add test to npmignores [ci skip]. (@hzoo)
• babylon
  • #3413 move babylon to https://github.com/babel/babylon. (@kittens)

v6.7.1

6.7.1 (2016-03-09)

Bug Fix

• babel-plugin-transform-es2015-block-scoping
  • #3411 Fixes T7197: Move bindings without losing any information.

The following code:

let foo = () => {
  foo = () => { };
};

foo();

Was generating:

var foo = function foo() {
  foo = function foo() {};
};

foo();

Notice how the function name foo was is shadowing the upper scope variable. This was fixed and the generated code now is:

var _foo = function foo() {
  _foo = function foo() {};
};

_foo();

v6.7.0

6.7.0 (2016-03-08)

Notable changes:

• Various async function fixes (const read-only error, wrong this, etc)
• Proper sourcemaps for import/export statements
• Moved internal Babel cache out of the AST

New Feature

• babel-traverse
  • #3393 Move NodePath cache out of the AST. (@amasad)

Move cache into a clearable WeakMap, adds traverse.clearCache and traverse.copyCache. This doubles as a bug fix because previously reusable AST Nodes would carry their cache with them even if they're used across multiple files and transform passes.

• babel-generator, babel-plugin-transform-flow-comments, babel-plugin-transform-flow-strip-types, babylon
  • #3385 Add support for Flow def-site variance syntax. (@samwgoldman)

// examples
class C<+T,-U> {}
function f<+T,-U>() {}
type T<+T,-U> = {}

This syntax allows you to specify whether a type variable can appear in
a covariant or contravariant position, and is super useful for, say,
Promise. @samwgoldman can tell you more 😄.

• babel-generator, babylon
  • #3323 Source-map support for multiple input source files. (@divmain)

More docs on this in the babel-generator README

Bug Fix

• babel-traverse
  • #3406 Update scope info after block-scoping transform T2892. (@amasad)

Make sure all existing let/const bindings are removed and replaced with vars after the block-scoping plugin is run.

This fixes: SyntaxError: src/foo.js: "baz" is read-only (This is an error on an internal node. Probably an internal error. Location has been estimated.)

async function foo() {
  async function bar() {
    const baz = {}; // was creating a read-only error
  }
}

• babel-core, babel-traverse, babel-helper-remap-async-to-generator, babel-helper-replace-supers, babel-plugin-transform-async-to-generator, babel-plugin-transform-async-to-module-method
  • #3405 Fix shadow function processing for async functions (@loganfsmyth)

Should fix the majority of issues dealing with async functions and use of parameters, this, and arguments.

// fixes
class Test {
  static async method2() {
    setTimeout(async (arg) => {
      console.log(this); // was showing undefined with arg
    });
  }

  async method2() {
    setTimeout(async (arg) => {
      console.log(this); // was showing undefined with arg
    });
  }
}

• babel-helper-remap-async-to-generator, babel-plugin-transform-async-to-generator, babel-plugin-transform-async-to-module-method
  • #3381 Fix named async FunctionExpression scoping issue.. (@keijokapp)

The problem is that the name bar of FunctionExpression is only visible inside that function, not in foo or ref.

// input
var foo = async function bar() {
  console.log(bar);
};


// before
var foo = function () {
  var ref = babelHelpers.asyncToGenerator(function* () {
    console.log(bar);
  });

  return function bar() {
    return ref.apply(this, arguments);
  };
}();

// now
var foo = function () {
  var ref = babelHelpers.asyncToGenerator(function* () {
    console.log(bar);
  });

  function bar() {
    return ref.apply(this, arguments);
  }

  return bar
}();

• babel-plugin-transform-es2015-parameters
  • #3375 Fix errors in parameters rest transformation T7138. (@jmm)

Many fixes to rest params: function asdf(...rest) { ... }

• babel-template
  • #3363 Fix usage in IE <= 9 (@danez)
• babel-plugin-transform-es2015-modules-commonjs
  • #3409 Fix source map generation for import and export statement.

Internal

• babel-plugin-transform-es2015-modules-commonjs
  • #3383 Test for regression with exporting an arrow function with a default param. (@hzoo)

Commiters: 6

amasad, divmain, hzoo, jmm, keijokapp, loganfsmyth, samwgoldman

v6.6.5

6.6.5 (2016-03-04)

And.. some more bug fixes!

Bug Fix

• babel-plugin-transform-es2015-computed-properties
  • #3396 Fixes T7183: Object accessors after computed property were broken. (@AgentME)

// lead to `ReferenceError: b is not defined` at runtime
var obj = {
  ["a"]: 5,
  set b(x) { console.log('set b', x); }
};

obj.b = 55;

• babel-plugin-transform-object-rest-spread, babel-types
  • #3395 Recognize object rest properties as binding identifiers - Fixes T7178. (@loganfsmyth)

import props from 'props';
console.log(props);

(function(){
  const { ...props } = this.props;

  console.log(props); // props was referencing the imported props rather than in object spread
})();

• babel-plugin-transform-es2015-block-scoping
  • #3389 Update scope binding info after transforming block-scoped bindings. (@amasad)

Scope binding info wasn't updated after converting const/let/block bindings to var which could lead to errors with other transforms.

Internal

• #3398 Revert "Remove flow". (@amasad)
• #3397 Make sure lib is clean before publishing. (@hzoo)
• babel-core, babel-plugin-transform-es2015-block-scoping, babel-plugin-transform-es2015-classes
  • #3399 use flow instead of flow-comments. (@hzoo)
• babel-plugin-transform-es2015-modules-amd, babel-plugin-transform-es2015-modules-commonjs, babel-plugin-transform-es2015-modules-umd
  • #3391 Make buildExportAll generate pure ES5 code.. (@benjamn)

Commiters: 5

AgentME, amasad, benjamn, hzoo, loganfsmyth

v6.6.4

6.6.4 (2016-03-02)

Some more fixes!

Bug Fix

• babel-plugin-transform-es2015-duplicate-keys
  • #3388 Partial T7173 Fix: Prevent accessors being seen as duplicates of each other. (@AgentME)

// sample code that was erroring
const obj = {
  set a (a) {
    values.a = a;   
  },
  get a () {
    return values.a;
  }
};

• babel-core
  • #3350 Make Babel actually resolve plugins relative to where they were specified (via .babelrc).. (@skevy)

// .babelrc
{
  "plugins": ["./myPluginDir/somePlugin.js"]
}

Babel will now resolve the plugin above relative to the directory that contains the .babelrc file rather than the process.cwd().

Internal

• A lot of packages
  • #3392 Remove flow. (@samwgoldman)

Users were getting error reports with flow when running on Babel's codebase. (Ref T7114) - Will be adding it back into the codebase itself soon.

v6.6.3

6.6.3 (2016-03-01)

Bug Fix

• babel-plugin-transform-es2015-modules-commonjs, babel-traverse
  • #3387 Fix regression with T7165 - let is not being transpiled when using export all (block-scoping transform wasn't run) (@loganfsmyth)

// example code
`export * from './a'`

v6.6.2

6.6.2 (2016-03-01)

Bug Fix

• babel-plugin-transform-es2015-modules-commonjs, babel-traverse
  • #3386 Fix regression with T7160 - exported arrow functions with default parameters (@loganfsmyth)

// example code
export var bar = (gen, ctx = null) => {}

v6.6.1

6.6.1 (2016-02-29)

Bug Fix

• babel-runtime, babel-polyfill: Fix publishing issue (wasn't updated from before).

v6.6.0

6.6.0 (2016-02-29) "core-js 2, better error feedback"

Whoo a 🐸 leap day release!

exports.default fix

We finally fixed both T2817, T6863 where using both transform-es3-member-expression-literals and transform-es2015-modules-commonjs!

exports.default = {};
// was not to transformed to
exports["default"] = {};

You should be able to remove es3ify (a useful workaround for this issue). Thanks everyone for your patience, and much thanks to @loganfsmyth for the fix!

More helpful error messages

• If you are using a .babelrc with babel 5 options that were removed (there is a specific message for each one)

# before
ReferenceError: [BABEL] unknown: Unknown option: base.stage
# now
ReferenceError: [BABEL] unknown: Using removed Babel 5 option: base.stage
- Check out the corresponding stage-x presets http://babeljs.io/docs/plugins/#presets
# another example
ReferenceError: [BABEL] unknown: Using removed Babel 5 option: base.externalHelpers
- Use the `external-helpers` plugin instead. Check out http://babeljs.io/docs/plugins/external-helpers/

• If you are trying to use a babel 5 plugin

# before
babel Plugin is not a function
# now
The object-assign Babel 5 plugin is being run with Babel 6.

core-js

• core-js was updated to ^2.1.0.

---

New Feature

New plugin babel-plugin-transform-es2015-duplicate-keys

• babel-plugin-transform-es2015-duplicate-keys, babel-preset-es2015
  • #3280 Fixes T2462, compile duplicate keys in objects to valid strict ES5. (@AgentME)

babel-plugin-transform-es2015-duplicate-keys is a new plugin that is included in the es2015 preset. It was added since ES5 doesn't allow duplicate properties (it is valid in ES2015 strict mode however).

It will compile objects with duplicate keys to computed properties, which can be compiled with the transform-es2015-computed-properties plugin.

Example:

// .babelrc
{ "plugins": ["transform-es2015-duplicate-keys"] }
// Input
var x = { a: 5, "a": 6 };
// Output
var x = { a: 5, ["a"]: 6 };

New globals option for transform-es2015-modules-umd

• babel-plugin-transform-es2015-modules-umd
  • #3366 [UMD] Fixed T6832. (@clayreimann)

// Adds a new plugin option to let you override the names of globals
// .babelrc
{
  "plugins": [
    ["transform-es2015-modules-umd", {
      "globals": {
        "es6-promise": "Promise"
      }
    }]
  ]
}

Bug Fix

• babel-plugin-transform-es2015-modules-commonjs, babel-traverse
  • #3368 Fix the module plugin to properly requeue so the ES3 transforms can work. (@loganfsmyth)
• babylon
  • #3355 Clean up babylon bundle to allow it to be re-bundled - Fixes T6930. (@loganfsmyth)
• babel-generator
  • #3358 Fix generator with empty token list and force a newline for line comments in concise mode. (@gzzhanghao)
• babel-plugin-transform-es2015-parameters
  • #3249 Assignment to rest param element triggers error T6932. (@jmm)

// .babelrc
{ plugins: ["transform-es2015-parameters"] }

// Fixes an internal error with the code:
function x (...items) {
  items[0] = 0;
}

• babel-helper-remap-async-to-generator, babel-plugin-transform-es2015-parameters
  • #3336 Fixes T3077 (incorrect _arguments for async arrow functions with rest params). (@erikdesjardins)

// .babelrc
{
  "plugins": ["external-helpers", "transform-es2015-parameters", "transform-async-to-generator"]
}

// Fixes an issue with using incorrect `arguments`
var x = async (...rest) => {
  if (noNeedToWork) return 0;
  return rest;
};

• babel-plugin-transform-regenerator, babel-traverse
  • #3359 Queue regeneratorRuntime so it is transformed before Program#exit. (@loganfsmyth)

Fixes the _regeneratorRuntime is not defined error when using transform-runtime/transform-regenerator (this happened when using polyfillable code in core-js.

• babylon
  • #3356 Properly fail to parse >== and <== - Fixes T2921. (@loganfsmyth)
• babel-plugin-transform-es2015-block-scoping
  • #3346 Rename scope bindings during block scope transform. (@schmod)
• babel-generator
  • #3380 Fix: Add parens for unary arrow function. (@hzoo)

// input
void (() => {});
// correct output
void (() => {});
// wrong
void () => {};

• babel-generator
  • #3379 Fix: invalid codegen for non decimal numeric literals in MemberExpression. (@hzoo)

// input
(0xFFFF).toString()
// correct output
0xFFFF.toString()
// wrong
0xFFFF..toString()

Documentation

• babel-plugin-transform-regenerator
  • #3370 Adds repository field to babel-plugin-transform-regenerator. (@siroky)
• babel-plugin-transform-object-set-prototype-of-to-assign
  • #3369 fix babel-plugin-transform-proto-to-assign readme url. (@tiemevanveen)
• babel-cli
  • #3357 Fix typo: sorucemap -> sourcemap. (@forivall)

Internal

• #3378 Remove Flow annotations and pragmas. (@samwgoldman)
• #3361 Switch to kcheck*, fix some lint rules. (@kittens)
• babel-plugin-transform-runtime, babel-polyfill, babel-register, babel-runtime
  • #3340 update core-js. (@zloirock)

Polish

• babel-core, babel-traverse
  • #3365 Replace arrow expression body with block statement. (@jridgewell)
• babel-core
  • #3362 Show a better error when trying to use a babel 5 plugin. (@hzoo)
• babel-core
  • #3377 Give specific error messages for babel 5 options that were removed in babel 6. (@hzoo)

---

We have 15 committers this release!

Thanks to: AgentME, clayreimann, erikdesjardins, forivall, gzzhanghao, hzoo, jmm, jridgewell, kittens, loganfsmyth, samwgoldman, schmod, siroky, tiemevanveen, zloirock