@hishprorg/optio-incidunt

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.

Getting started

1npm install --save @hishprorg/optio-incidunt

Usage/Examples

1var flat = require('@hishprorg/optio-incidunt');
2var assert = require('assert');
3
4var arr = [1, [2], [], 3, [[4]]];
5
6assert.deepEqual(flat(arr, 1), [1, 2, 3, [4]]);

1var flat = require('@hishprorg/optio-incidunt');
2var assert = require('assert');
3/* when Array#flat is not present */
4delete Array.prototype.flat;
5var shimmedFlat = flat.shim();
6
7assert.equal(shimmedFlat, flat.getPolyfill());
8assert.deepEqual(arr.flat(), flat(arr));

1var flat = require('@hishprorg/optio-incidunt');
2var assert = require('assert');
3/* when Array#flat is present */
4var shimmedIncludes = flat.shim();
5
6var mapper = function (x) { return [x, 1]; };
7
8assert.equal(shimmedIncludes, Array.prototype.flat);
9assert.deepEqual(arr.flat(mapper), flat(arr, mapper));

Tests

Simply clone the repo, npm install, and run npm test