Release v6.18.0 · babel/babel

v6.18.0 (2016-10-24)

🚀 New Feature

babel-generator, babel-plugin-transform-flow-strip-types
- #4697 Add variance node type and generate property variance annotations. (@samwgoldman)

Check out the blog post and flow docs for more info:

type T = { +p: T };
interface T { -p: T };
declare class T { +[k:K]: V };
class T { -[k:K]: V };
class C2 { +p: T = e };

babel-core, babel-traverse
- #4746 Support ObjectExpression in static path evaluation. (@motiz88)

// in
['a' + 'b']: 10 * 20, 'z': [1, 2, 3]}
// out
{ab: 200, z: [1, 2, 3]}

babel-plugin-syntax-dynamic-import, babel-preset-stage-2
- #4699 [import()] Initial support for dynamic-import. (@kesne)

Parser support was added in https://github.com/babel/babylon/releases/tag/v6.12.0.

Just the plugin to enable it in babel.

// install
$ npm install babel-plugin-syntax-dynamic-import --save-dev

or use the new parserOpts

// .babelrc
{
  "parserOpts": {
    "plugins": ['dynamicImport']
  }
}

babel-helper-builder-react-jsx, babel-plugin-transform-react-jsx
- #4655 Add useBuiltIns option to helper-builder-react-jsx. (@existentialism)

Previously we added a useBuiltIns for object-rest-spread so that it use the native/built in version if you use a polyfill or have it supported natively.

This change just uses the same option from the plugin to be applied with spread inside of jsx.

// in
var div = <Component {...props} foo="bar" />
// out
var div = React.createElement(Component, Object.assign({}, props, { foo: "bar" }));

babel-generator, babel-traverse, babel-types
- #4724 Add EmptyTypeAnnotation. (@samwgoldman)

EmptyTypeAnnotation

Added in flow here and in babylon here.

function f<T>(x: empty): T {
  return x;
}
f(); // nothing to pass...

babel-traverse
- #4758 Make getBinding ignore labels; add Scope#getLabel, Scope#hasLabel, Scope#registerLabel. (@kangax)

Track LabeledStatement separately (not part of bindings).

🐛 Bug Fix

Will give examples of code that was fixed below

babel-plugin-transform-react-inline-elements, babel-traverse
- #4765 Don't treat JSXIdentifier in JSXMemberExpression as HTML tag. Closes #4027. (@DrewML)

// issue with imported components that were JSXMemberExpression
import { form } from "./export";

function ParentComponent() {
  return <form.TestComponent />;
}

babel-plugin-transform-es2015-modules-commonjs, babel-plugin-transform-react-inline-elements
- #4763 Handle remapping of JSXIdentifier to MemberExpression in CommonJS transform. Closes #3728. (@DrewML)

import { Modal } from "react-bootstrap";
export default CustomModal = () => <Modal.Header>foobar</Modal.Header>;

babel-plugin-transform-es2015-for-of
- #4736 Fix replacing for-of if inside label. (@danez)

if ( true ) {
  loop: for (let ch of []) {}
}

babel-core
- #4502 Make special case for class property initializers in shadow-functions. (@motiz88)

class A {
  prop1 = () => this;
  static prop2 = () => this;
  prop3 = () => arguments;
}

#4631 fix(shouldIgnore): filename normalization should be platform sensitive. (@rozele)
- babel-helper-remap-async-to-generator, babel-plugin-transform-async-generator-functions
#4719 Fixed incorrect compilation of async iterator methods. (@Jamesernator)

// in
class C {
  async *g() { await 1; }
}
// out
class C {
  g() { // was incorrectly outputting the method with a generator still `*g(){`
    return _asyncGenerator.wrap(function* () {
      yield _asyncGenerator.await(1);
    })();
  }
}

babel-plugin-check-es2015-constants, babel-plugin-transform-es2015-destructuring, babel-plugin-transform-es2015-modules-commonjs, babel-plugin-transform-es2015-parameters
- #4690 Consolidate contiguous var declarations in destructuring transform. (@motiz88)

// was wrapping variables in an IIFE incorrectly
for ( let i = 0, { length } = list; i < length; i++ ) {
    console.log( i + ': ' + list[i] )
}

babel-plugin-transform-es2015-parameters
- #4666 Fix error when constructor default arg refers to self or own static property. (@danharper)

// was producing invalid code
class Ref {
  static nextId = 0
  constructor(id = ++Ref.nextId, n = id) {
    this.id = n
  }
}

assert.equal(1, new Ref().id)
assert.equal(2, new Ref().id)

#4674 Handle side effects correctly in rest params index expressions (#4348). (@motiz88)

function first(...values) {
    let index = 0;
    return values[index++]; // ++ was happening twice
}

console.log(first(1, 2));

babel-plugin-transform-es2015-block-scoping
- #4669 Fix block scoping transform for declarations in labeled statements. (@motiz88)

let x = 10;
if (1)
{
    ca: let x = 20;
}

babel-helper-explode-assignable-expression, babel-plugin-transform-exponentiation-operator
- #4672 Avoid repeating impure (template) literals when desugaring **= (#4403). (@motiz88)

a[`${b++}`] **= 1;

#4642 Exclude super from being assign to ref variable. (@danez)
- babel-plugin-transform-es2015-shorthand-properties, babel-plugin-transform-flow-comments, babel-plugin-transform-flow-strip-types

foo = {
  bar() {
    return super.baz **= 12;
  }
}

#4670 Retain return types on ObjectMethods in transform-es2015-shorthand-properties. (@danharper)

// @flow
var obj = {
  method(a: string): number {
    return 5 + 5;
  }
};

babel-helper-define-map, babel-plugin-transform-es2015-classes, babel-plugin-transform-flow-comments, babel-plugin-transform-flow-strip-types
- #4668 Retain method return types on transform-es2015-classes (Closes #4665). (@danharper)

// @flow
class C {
  m(x: number): string {
    return 'a';
  }
}

💅 Polish

babel-plugin-check-es2015-constants, babel-plugin-transform-es2015-destructuring, babel-plugin-transform-es2015-modules-commonjs, babel-plugin-transform-es2015-parameters
- #4690 Consolidate contiguous var declarations in destructuring transform. (@motiz88)

// in
const [a, b] = [1, 2];
// out
var a = 1,
    b = 2;

babel-plugin-transform-es2015-parameters
- #4738 Avoid unnecessary +0 in transform-es2015-parameters. (@existentialism)

// was outputting an extra `index++ + 0`
function first(...values) {
  var index = 0;
  return values[index++];
}

babel-core
- #4685 Better error messaging when preset options are given without a corresponding preset. (@kaicataldo)

We've had a few reports of users not wrapping a preset in [] when passing in options so we added an extra error message for this.

ReferenceError: [BABEL] /test.js: Unknown option: base.loose2. Check out http://babeljs.io/docs/usage/options/ for more information about options.

A common cause of this error is the presence of a configuration options object without the corresponding preset name. Example:

Invalid:
  `{ presets: [{option: value}] }`
Valid:
  `{ presets: ["pluginName", {option: value}] }`

For more detailed information on preset configuration, please see http://babeljs.io/docs/plugins/#pluginpresets-options.

#4688 Update babel parser options. (@existentialism)
babel-generator
- #4646 Change babel-generator to output boolean instead of bool for the BooleanTypeAnnotation AST node. (@existentialism)

var a: Promise<boolean>[];
// instead of
var a: Promise<bool>[];

Documentation

Other
- #4653 Tweak license for GitHub display. (@existentialism)

So that our MIT License shows up.

🏠 Internal

babel-cli
- #4725 Remove babel-doctor from babel-cli. (@kaicataldo)

It's a one-time use tool (helpful after the initial release when upgrading from v5 to v6) that doesn't need to be a part of babel-cli. We'll publish it as a standalone package it someone asks for it.

Other
- #4764 Add TEST_DEBUG env var option for test.sh, to enable node 6 debugger. (@DrewML)
- #4762 Update browserify to version 13.1.1 🚀. (@greenkeeperio-bot)
- #4748 Add clean-all command to reinstall node_modules. (@kaicataldo)
- #4744 Fix line endings on checkout. (@nhajidin)
- #4730 Add .gitattributes forcing LF line endings. (@motiz88)
- #4676 Remove travis short-circuit script. (@motiz88)
babel-traverse, babel-types
- #4742 Increase test coverage. (@motiz88)
babel-cli, babel-core, babel-helper-fixtures, babel-register
- #4731 Replace path-exists with fs.existsSync. (@SimenB)
babel-helper-transform-fixture-test-runner
- #4735 Automatically generate missing expected.js fixtures. (@motiz88)
- #4664 🚀 Update chai to version 3.0.0. (@danez)
babel-cli, babel-code-frame, babel-core, babel-generator, babel-helper-transform-fixture-test-runner, babel-preset-es2015, babel-template, babel-traverse
- #4734 Change usage of "suite"/"test" in unit-tests to "describe"/"it". (@DrewML)
babel-cli, babel-code-frame, babel-core, babel-generator, babel-plugin-transform-es2015-modules-commonjs, babel-preset-es2015, babel-template, babel-traverse
- #4732 Run ESLint on test files, and fix lint errors in test files.. (@DrewML)
babel-cli, babel-core
- #4727 Update tests for changed error messages in Babylon. (@motiz88)
- #4564 Enable babel for tests. (@danez)
babel-cli, babel-core, babel-plugin-transform-es2015-modules-systemjs, babel-preset-es2015
- #4721 update eslint-config, fixes, add commands. (@hzoo)
babel-register
- #4660 🚀 Update home-or-tmp to version 2.0.0. (@danez)
babel-cli
- #4680 Update: Eslint to 3.0 and update CI builds (Closes #4638). (@gyandeeps)
- #4662 🚀 Update fs-readdir-recursive to 1.0.0. (@danez)
babel-core
- #4649 🚀 Update json5 to version 0.5.0. (@danez)
- #4650 🚀 Remove shebang dependency. (@danez)
babel-generator
- #4652 🚀 Update detect-indent to version 4.0.0. (@danez)
babel-traverse
- #4651 🚀 Update globals to version 9.0.0. (@danez)

Commiters: 17

Andrew Levine (DrewML)
Brian Ng (existentialism)
Dan Harper (danharper)
Daniel Tschinder (danez)
Eric Rozell (rozele)
Greenkeeper (greenkeeperio-bot)
Gyandeep Singh (gyandeeps)
Henry Zhu (hzoo)
Jordan Gensler (kesne)
Juriy Zaytsev (kangax)
Kai Cataldo (kaicataldo)
Moti Zilberman (motiz88)
Nazim Hajidin (nhajidin)
Sam Goldman (samwgoldman)
Simen Bekkhus (SimenB)
Jamesernator
sugargreenbean

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v6.18.0