https://github.com/tc39/proposal-object-rest-spread

Rest/Spread Properties for ECMAScript
https://github.com/tc39/proposal-object-rest-spread

Last synced: 3 months ago
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Rest/Spread Properties for ECMAScript

• Host: GitHub
• URL: https://github.com/tc39/proposal-object-rest-spread
• Owner: tc39
• Archived: true
• Created: 2014-07-30T06:05:03.000Z (over 10 years ago)
• Default Branch: main
• Last Pushed: 2022-01-24T19:18:52.000Z (almost 3 years ago)
• Last Synced: 2024-07-31T22:12:36.839Z (4 months ago)
• Language: HTML
• Homepage:
• Size: 84 KB
• Stars: 1,494
• Watchers: 69
• Forks: 85
• Open Issues: 14
• Metadata Files:
  • Readme: README.md

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README

        
Object Rest/Spread Properties for ECMAScript

--------------------------------------------

ECMAScript 6 introduces [rest elements](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment) for array destructuring assignment and [spread elements](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator) for array literals.

This proposal introduces analogous [rest properties](Rest.md) for object destructuring assignment and [spread properties](Spread.md) for object literals.

### [Specification](https://tc39.github.io/proposal-object-rest-spread/)

[Specification](https://tc39.github.io/proposal-object-rest-spread/)

### [Rest Properties](Rest.md)

Rest properties collect the remaining own enumerable property keys that are not already picked off by the destructuring pattern. Those keys and their values are copied onto a new object.

```javascript

let { x, y, ...z } = { x: 1, y: 2, a: 3, b: 4 };

x; // 1

y; // 2

z; // { a: 3, b: 4 }

```

### [Spread Properties](Spread.md)

Spread properties in object initializers copies own enumerable properties from a provided object onto the newly created object.

```javascript

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

n; // { x: 1, y: 2, a: 3, b: 4 }

```

### Transpilers

[Babel](https://babeljs.io/docs/plugins/transform-object-rest-spread/)

[Bublé](https://github.com/Rich-Harris/buble/)

[JSTransform](https://github.com/facebook/jstransform)

[TypeScript](https://github.com/Microsoft/TypeScript)

## [Status of this Proposal](https://github.com/tc39/ecma262)

It is a Stage 4 proposal for ECMAScript.

## [Known Issues](Issues.md)

This proposal only iterates over __own__ properties. [See why this matters.](Issues.md)