@babel/plugin-transform-destructuring

NOTE: This plugin is included in @babel/preset-env

Examples

In

let { x, y } = obj;
let [a, b, ...rest] = arr;

Out

function _toArray(arr) { ... }
let _obj = obj,
    x = _obj.x,
    y = _obj.y;
let _arr = arr,
    _arr2 = _toArray(_arr),
    a = _arr2[0],
    b = _arr2[1],
    rest = _arr2.slice(2);

Installation

npm install --save-dev @babel/plugin-transform-destructuring

Usage

With a configuration file (Recommended)

{
  "plugins": ["@babel/plugin-transform-destructuring"]
}

Via CLI

babel --plugins @babel/plugin-transform-destructuring script.js

Via Node API

require("@babel/core").transformSync("code", {
  plugins: ["@babel/plugin-transform-destructuring"],
});

Options

loose

boolean, defaults to false.

Enabling this option will assume that what you want to destructure is an array and won’t use Array.from on other iterables.

⚠️ Consider migrating to the top level iterableIsArray assumption.

// babel.config.json
{
  "assumptions": {
    "iterableIsArray": true
  }
}

useBuiltIns

boolean, defaults to false.

Enabling this option will use Object.assign directly instead of the Babel’s extends helper.

Example

.babelrc

{
  "plugins": [
    ["@babel/plugin-transform-destructuring", { "useBuiltIns": true }]
  ]
}

In

var { ...x } = z;

Out

var _z = z,
  x = Object.assign({}, _z);

You can read more about configuring plugin options here

allowArrayLike

boolean, defaults to false

Added in: v7.10.0

This option allows destructuring array-like objects using the array destructuring syntax.

An array-like object is an object with a length property: for example, { 0: "a", 1: "b", length: 2 }. Note that, like real arrays, array-like objects can have “holes”: { 1: "a", length: 3 } is equivalent to [ (hole), "a", (hole) ].

While it is not spec-compliant to destructure array-like objects as if they were arrays, there are many objects that would be iterables in modern browsers with Symbol.iterator support. Some notable examples are the DOM collections, like document.querySelectorAll("img.big"), which are the main use case for this option.

Please note that Babel allows destructuring arguments in old engines even if this option is disabled, because it’s defined as iterable in the ECMAScript specification.

⚠️ Consider migrating to the top level arrayLikeIsIterable assumption.

// babel.config.json
{
  "assumptions": {
    "arrayLikeIsIterable": true
  }
}

References

• MDN: Destructuring assignment