babel-plugin-transform-object-rest-spread

What is babel-plugin-transform-object-rest-spread?

The babel-plugin-transform-object-rest-spread package allows developers to use the object rest and spread properties syntax in their JavaScript code. This syntax is part of the ECMAScript 2018 (ES9) specification and enables more concise and readable code when copying properties from one object to another or collecting the remaining properties of an object after certain properties have been extracted.

What are babel-plugin-transform-object-rest-spread's main functionalities?

Object Spread

Allows an object's own enumerable properties to be copied into a new object. This is useful for creating a new object with the same properties as an existing object or for combining multiple objects.

{...source}

Object Rest

Enables extracting properties from objects and binding the remaining properties to a new object. This is useful for object destructuring, where you want to separate certain properties from the rest.

{a, b, ...rest}

Other packages similar to babel-plugin-transform-object-rest-spread

@babel/plugin-proposal-object-rest-spread

This is the official Babel plugin for transforming object rest and spread syntax. It is similar to babel-plugin-transform-object-rest-spread but is maintained as part of the Babel 7 release. It is the recommended package to use for Babel 7 users.

babel-preset-stage-3

This preset includes various Babel plugins for JavaScript features that are in stage 3 of the TC39 process, including object rest and spread properties. It is broader in scope compared to babel-plugin-transform-object-rest-spread, which focuses only on object rest and spread properties.

README

babel-plugin-transform-object-rest-spread

This plugin allows Babel to transform rest properties for object destructuring assignment and spread properties for object literals.

Example

// Rest properties
let { x, y, ...z } = { x: 1, y: 2, a: 3, b: 4 };
console.log(x); // 1
console.log(y); // 2
console.log(z); // { a: 3, b: 4 }

// Spread properties
let n = { x, y, ...z };
console.log(n); // { x: 1, y: 2, a: 3, b: 4 }

Try in REPL

Installation

npm install --save-dev babel-plugin-transform-object-rest-spread

Usage

Via .babelrc (Recommended)

.babelrc

{
  "plugins": ["transform-object-rest-spread"]
}

Options

This plugin will use babel's extends helper, which will polyfill Object.assign by default.

• useBuiltIns - Do not use Babel's helper's and just transform to use the built-in method (Disabled by default).

{
  "plugins": [
    ["transform-object-rest-spread", { "useBuiltIns": true }]
  ]
}

// source
z = { x, ...y };
// compiled
z = Object.assign({ x }, y);

Via CLI

babel --plugins transform-object-rest-spread script.js

Via Node API

require("babel-core").transform("code", {
  plugins: ["transform-object-rest-spread"]
});

References

• Proposal: Object Rest/Spread Properties for ECMAScript
• Spec