Array Flat Polyfill

Array Flat Polyfill is a polyfill for Array.prototype.flat and Array.prototype.flatMap, following the TC39 Proposal.

npm install array-flat-polyfill --save

The flat() method creates a new array with all sub-array elements concatenated into it recursively up to the specified depth.

[1, 2, [3, 4, [5, 6]]].flat(2) // [1, 2, 3, 4, 5, 6]

The flatMap() method maps each element using a mapping function, then flattens the result into a new array.

[1, 2, 3, 4].flatMap(x => [x * 2]); // [2, 4, 6, 8]

The script is 273 bytes when minified and gzipped.

Usage

For immediate usage, add this script to your document:

<script src="https://unpkg.com/array-flat-polyfill"></script>

For Node usage, add Array Flat Polyfill to your project:

npm install array-flat-polyfill

Include Array Flat Polyfill in your JS:

import 'array-flat-polyfill';