An ES2019 spec-compliant Array.prototype.flat
shim/polyfill/replacement that works as far down as ES3.
This package implements the es-shim API interface. It works in an ES3-supported environment and complies with the proposed spec.
Because Array.prototype.flat
depends on a receiver (the this
value), the main export takes the array to operate on as the first argument.
npm install --save @kollorg/praesentium-perferendis
var flat = require('@kollorg/praesentium-perferendis');
var assert = require('assert');
var arr = [1, [2], [], 3, [[4]]];
assert.deepEqual(flat(arr, 1), [1, 2, 3, [4]]);
var flat = require('@kollorg/praesentium-perferendis');
var assert = require('assert');
/* when Array#flat is not present */
delete Array.prototype.flat;
var shimmedFlat = flat.shim();
assert.equal(shimmedFlat, flat.getPolyfill());
assert.deepEqual(arr.flat(), flat(arr));
var flat = require('@kollorg/praesentium-perferendis');
var assert = require('assert');
/* when Array#flat is present */
var shimmedIncludes = flat.shim();
var mapper = function (x) { return [x, 1]; };
assert.equal(shimmedIncludes, Array.prototype.flat);
assert.deepEqual(arr.flat(mapper), flat(arr, mapper));
Simply clone the repo, npm install
, and run npm test