babylon

v6.12.0 (2016-10-14)

👓 Spec Compliancy

Implement import() syntax (#163) (Jordan Gensler)

Dynamic Import

• Proposal Repo: https://github.com/domenic/proposal-dynamic-import
• Championed by @domenic
• stage-2
• sept-28 tc39 notes

This repository contains a proposal for adding a "function-like" import() module loading syntactic form to JavaScript

import(`./section-modules/${link.dataset.entryModule}.js`)
.then(module => {
  module.loadPageInto(main);
})

Add EmptyTypeAnnotation (#171) (Sam Goldman)

EmptyTypeAnnotation

Just wasn't covered before.

type T = empty;

:bug: Bug Fix

Fix crash when exporting with destructuring and sparse array (#170) (Jeroen Engels)

// was failing due to sparse array
export const { foo: [ ,, qux7 ] } = bar;

Allow keyword in Flow object declaration property names with type parameters (#146) (Dan Harper)

declare class X {
  foobar<T>(): void;
  static foobar<T>(): void;
}

Allow keyword in object/class property names with Flow type parameters (#145) (Dan Harper)

class Foo {
  delete<T>(item: T): T {
    return item;
  }
}

Allow typeAnnotations for yield expressions (#174)) (Daniel Tschinder)

function *foo() {
  const x = (yield 5: any);
}

:nail_care: Polish

Annotate more errors with expected token (#172)) (Moti Zilberman)

// Unexpected token, expected ; (1:6)
{ set 1 }

:house: Internal

Remove kcheck (#173)) (Daniel Tschinder)

Also run flow, linting, babel tests on seperate instances (add back node 0.10)

v6.11.6 (2016-10-12)

:bug: Bug Fix/Regression

Fix crash when exporting with destructuring and sparse array (#170) (Jeroen Engels)

// was failing with `Cannot read property 'type' of null` because of null identifiers
export const { foo: [ ,, qux7 ] } = bar;

v6.11.5 (2016-10-12)

:eyeglasses: Spec Compliancy

Fix: Check for duplicate named exports in exported destructuring assignments (#144) (Kai Cataldo)

// `foo` has already been exported. Exported identifiers must be unique. (2:20)
export function foo() {};
export const { a: [{foo}] } = bar;

Fix: Check for duplicate named exports in exported rest elements/properties (#164) (Kai Cataldo)

// `foo` has already been exported. Exported identifiers must be unique. (2:22)
export const foo = 1;
export const [bar, ...foo] = baz;

:bug: Bug Fix

Fix: Allow identifier async for default param in arrow expression (#165) (Kai Cataldo)

// this is ok now
const test = ({async = true}) => {};

:nail_care: Polish

Babylon will now print out the token it's expecting if there's a SyntaxError (#150) (Daniel Tschinder)

# So in the case of a missing ending curly (`}`)
Module build failed: SyntaxError: Unexpected token, expected } (30:0)
  28 |   }
  29 |
> 30 |
     | ^

• Temporary rollback for erroring on trailing comma with spread (#154) (Henry Zhu)

v6.11.3 (2016-10-01)

:eyeglasses: Spec Compliancy

Add static errors for object rest (#149) (@danez)

https://github.com/sebmarkbage/ecmascript-rest-spread

Object rest copies the rest of properties from the right hand side obj starting from the left to right.

let { x, y, ...z } =  { x: 1, y: 2, z: 3 };
// x = 1
// y = 2
// z = { z: 3 }

New Syntax Errors:

SyntaxError: The rest element has to be the last element when destructuring (1:10)

> 1 | let { ...x, y, z } = { x: 1, y: 2, z: 3 };
    |           ^
# Previous behavior:
# x = { x: 1, y: 2, z: 3 }
# y = 2
# z = 3

Before, this was just a more verbose way of shallow copying obj since it doesn't actually do what you think.

SyntaxError: Cannot have multiple rest elements when destructuring (1:13)

> 1 | let { x, ...y, ...z } = { x: 1, y: 2, z: 3 };
    |              ^
# Previous behavior:
# x = 1
# y = { y: 2, z: 3 }
# z = { y: 2, z: 3 }

Before y and z would just be the same value anyway so there is no reason to need to have both.

SyntaxError: A trailing comma is not permitted after the rest element (1:16)

let { x, y, ...z, } = obj;

The rationale for this is that the use case for trailing comma is that you can add something at the end without affecting the line above. Since a RestProperty always has to be the last property it doesn't make sense.

---

get / set are valid property names in default assignment (#142) (@jezell)

// valid
function something({ set = null, get = null }) {}

Bug Fix

• #139 Don't do the duplicate check if not an identifier (#140) @hzoo

// regression with duplicate export check
SyntaxError: ./typography.js: `undefined` has already been exported. Exported identifiers must be unique. (22:13)
  20 | 
  21 | export const { rhythm } = typography;
> 22 | export const { TypographyStyle } = typography

Bail out for now, and make a change to account for destructuring in the next release.

Hot Fix

• #137 - Fix a regression with duplicate exports - it was erroring on all keys in Object.prototype. @danez

export toString from './toString';

`toString` has already been exported. Exported identifiers must be unique. (1:7)
> 1 | export toString from './toString';
    |        ^
  2 |

6.11.0 (2016-09-22)

Spec Compliancy

• Disallow duplicate named exports (#107) @kaicataldo

// Only one default export allowed per module. (2:9)
export default function() {};
export { foo as default };

// Only one default export allowed per module. (2:0)
export default {};
export default function() {};

// `Foo` has already been exported. Exported identifiers must be unique. (2:0)
export { Foo };
export class Foo {};

New Feature (Syntax)

• Add support for computed class property names (#121) @motiz88

// AST
interface ClassProperty <: Node {
  type: "ClassProperty";
  key: Identifier;
  value: Expression;
  computed: boolean; // added
}

// with "plugins": ["classProperties"]
class Foo {
  [x]
  ['y']
}

class Bar {
  [p]
  [m] () {}
}

Bug Fix

• Fix static property falling through in the declare class Flow AST (#135) @danharper

declare class X {
    a: number;
    static b: number; // static
    c: number; // this was being marked as static in the AST as well
}

Polish

• Rephrase "assigning/binding to rvalue" errors to include context (#119) @motiz88

// Used to error with:
// SyntaxError: Assigning to rvalue (1:0)

// Now:
// Invalid left-hand side in assignment expression (1:0)
3 = 4

// Invalid left-hand side in for-in statement (1:5)
for (+i in {});

Internal

• Fix call to this.parseMaybeAssign with correct arguments (#133) @danez
• Add semver note to changelog (#131) @hzoo

6.10.0 (2016-09-19)

We plan to include some spec compliancy bugs in patch versions. An example was the multiple default exports issue.

Spec Compliancy

• Implement ES2016 check for simple parameter list in strict mode (#106) (Timothy Gu)

It is a Syntax Error if ContainsUseStrict of FunctionBody is true and IsSimpleParameterList of FormalParameters is false. https://tc39.github.io/ecma262/2016/#sec-function-definitions-static-semantics-early-errors

More Context: tc39-notes

For example:

// this errors because it uses destructuring and default parameters
// in a function with a "use strict" directive
function a([ option1, option2 ] = []) {
  "use strict";
}

The solution would be to use a top level "use strict" or to remove the destructuring or default parameters when using a function + "use strict" or to.

New Feature

• Exact object type annotations for Flow plugin (#104) (Basil Hosmer)

Added to flow in https://github.com/facebook/flow/commit/c710c40aa2a115435098d6c0dfeaadb023cd39b8

Looks like:

var a : {| x: number, y: string |} = { x: 0, y: 'foo' };

Bug Fixes

• Include typeParameter location in ArrowFunctionExpression (#126) (Daniel Tschinder)
• Error on invalid flow type annotation with default assignment (#122) (Dan Harper)
• Fix Flow return types on arrow functions (#124) (Dan Harper)

Misc

• Add tests for export extensions (#127) (Daniel Tschinder)
• Fix Contributing guidelines [skip ci](Daniel Tschinder)

6.9.2 (2016-09-09)

The only change is to remove the babel-runtime dependency by compiling with Babel's ES2015 loose mode. So using babylon standalone should be smaller.

6.9.1 (2016-08-23)

This release contains mainly small bugfixes but also updates babylons default mode to es2017. The features for exponentiationOperator, asyncFunctions and trailingFunctionCommas which previously needed to be activated via plugin are now enabled by default and the plugins are now no-ops.

Bug Fixes

• Fix issues with default object params in async functions (#96) @danez
• Fix issues with flow-types and async function (#95) @danez
• Fix arrow functions with destructuring, types & default value (#94) @danharper
• Fix declare class with qualified type identifier (#97) @danez
• Remove exponentiationOperator, asyncFunctions, trailingFunctionCommas plugins and enable them by default (#98) @danez

6.9.0 (2016-08-16)

New syntax support

• Add JSX spread children (#42) @calebmer

(Be aware that React is not going to support this syntax)

<div>
  {...todos.map(todo => <Todo key={todo.id} todo={todo}/>)}
</div>

• Add support for declare module.exports (#72) @danez

declare module foo {
  declare module.exports: {}
}

New Features

• If supplied, attach filename property to comment node loc. (#80) @divmain
• Add identifier name to node loc field (#90) @kittens

Bug Fixes

• Fix exponential operator to behave according to spec (#75) @danez
• Fix lookahead to not add comments to arrays which are not cloned (#76) @danez
• Fix accidental fall-through in Flow type parsing. (#82) @xiemaisi
• Only allow declares inside declare module (#73) @danez
• Small fix for parsing type parameter declarations (#83) @gabelevi
• Fix arrow param locations with flow types (#57) @danez
• Fixes SyntaxError position with flow optional type (#65) @danez

Internal

• Add codecoverage to tests @danez
• Fix tests to not save expected output if we expect the test to fail @danez
• Make a shallow clone of babel for testing @danez
• chore(package): update cross-env to version 2.0.0 (#77) @greenkeeperio-bot
• chore(package): update ava to version 0.16.0 (#86) @greenkeeperio-bot
• chore(package): update babel-plugin-istanbul to version 2.0.0 (#89) @greenkeeperio-bot
• chore(package): update nyc to version 8.0.0 (#88) @greenkeeperio-bot

6.8.4 (2016-07-06)

Bug Fixes

• Fix the location of params, when flow and default value used (#68) Fixes #67 @danez

6.8.3 (2016-07-03)

Bug Fixes

• Fix performance regression introduced in 6.8.2 with conditionals #63 @danez

6.8.2 (2016-06-24)

Bug Fixes

• Fix parse error with yielding jsx elements in generators function* it() { yield <a></a>; }
• When cloning nodes do not clone its comments
• Fix parse errors when using arrow functions with an spread element and return type (...props): void => {}
• Fix leading comments added from previous node
• Fix parse errors with flow's optional arguments (arg?) => {}
• Support negative numeric type literals
• Remove line terminator restriction after await keyword
• Remove grouped type arrow restriction as it seems flow no longer has it
• Fix parse error with generic methods that have the name get or set class foo { get() {} }
• Fix parse error with arrow functions that have flow type parameter declarations <T>(x: T): T => x;

Documentation

• Document AST differences from ESTree
• Move ast spec from babel/babel

Internal

• Enable skipped tests
• Add script to test latest version of babylon with babel
• Upgrade test runner ava
• Add missing generate-identifier-regex script
• Rename parser context types
• Add node v6 to travis testing
• Update to Unicode v9

6.8.1 (2016-06-06)

New Feature

• Parse type parameter declarations with defaults like type Foo<T = string> = T

Bug Fixes

• Type parameter declarations need 1 or more type parameters.
• The existential type * is not a valid type parameter.
• The existential type * is a primary type

Spec Compliancy

• The param list for type parameter declarations now consists of TypeParameter nodes
• New TypeParameter AST Node (replaces using the Identifier node before)

interface TypeParameter <: Node {
  bound: TypeAnnotation;
  default: TypeAnnotation;
  name: string;
  variance: "plus" | "minus";
}

6.8.0 (2016-05-04)

This is also the first release of babylon outside of the main babel repo. We are able to parse two new features! This release is to correspond to the previous Babel 6.8.0 release since babylon is also compiled with Babel 6. In the future, the version numbers may not correspond the same given it's in a separate repo.

New Feature

Parse Method Parameter Decorators (#12)

Method Parameter Decorators is now a TC39 stage 0 proposal.

Examples:

class Foo {
  constructor(@foo() x, @bar({ a: 123 }) @baz() y) {}
}

export default function func(@foo() x, @bar({ a: 123 }) @baz() y) {}

var obj = {
  method(@foo() x, @bar({ a: 123 }) @baz() y) {}
};

Parse for-await statements (w/ asyncGenerators plugin) (#17)

There is also a new node type, ForAwaitStatement.

Async generators and for-await are now a stage 2 proposal.

Example:

async function f() {
  for await (let x of y);
}