An ESnext spec-compliant `Array.prototype.groupToMap` shim/polyfill/replacement that works as far down as ES3.
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An ESnext spec-compliant Array.prototype.groupToMap 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.groupToMap depends on a receiver (the this value), the main export takes the array to operate on as the first argument.
``sh`
npm install --save array.prototype.grouptomap
`js
var groupToMap = require('array.prototype.grouptomap');
var assert = require('assert');
var arr = [0, 1, 2, 3, 4, 5];
var parity = function (x) { return x % 2 === 0 ? 'even' : 'odd'; };
var results = groupToMap(arr, function (x, i, a) {
assert.equal(x, arr[i]);
assert.equal(a, arr);
return parity(x);
});
assert.deepEqual(results, new Map([
['even', [0, 2, 4]],
['odd', [1, 3, 5]],
]));
`
`js
var groupToMap = require('array.prototype.grouptomap');
var assert = require('assert');
/ when Array#groupToMap is not present /
delete Array.prototype.groupToMap;
var shimmed = groupToMap.shim();
assert.equal(shimmed, groupToMap.getPolyfill());
assert.deepEqual(arr.groupToMap(parity), groupToMap(arr, parity));
`
`js
var groupToMap = require('array.prototype.grouptomap');
var assert = require('assert');
/ when Array#groupToMap is present /
var shimmed = groupToMap.shim();
assert.equal(shimmed, Array.prototype.groupToMap);
assert.deepEqual(arr.groupToMap(parity), groupToMap(arr, parity));
`
, and run npm test`[package-url]: https://npmjs.org/package/array.prototype.grouptomap
[npm-version-svg]: https://versionbadg.es/es-shims/Array.prototype.groupToMap.svg
[deps-svg]: https://david-dm.org/es-shims/Array.prototype.groupToMap.svg
[deps-url]: https://david-dm.org/es-shims/Array.prototype.groupToMap
[dev-deps-svg]: https://david-dm.org/es-shims/Array.prototype.groupToMap/dev-status.svg
[dev-deps-url]: https://david-dm.org/es-shims/Array.prototype.groupToMap#info=devDependencies
[npm-badge-png]: https://nodei.co/npm/array.prototype.grouptomap.png?downloads=true&stars=true
[license-image]: https://img.shields.io/npm/l/array.prototype.grouptomap.svg
[license-url]: LICENSE
[downloads-image]: https://img.shields.io/npm/dm/array.prototype.grouptomap.svg
[downloads-url]: https://npm-stat.com/charts.html?package=array.prototype.grouptomap