https://github.com/es-shims/array.prototype.grouptomap
An ESnext spec-compliant `Array.prototype.groupToMap` shim/polyfill/replacement that works as far down as ES3.
https://github.com/es-shims/array.prototype.grouptomap
array ecmascript group groupby groupbytomap grouping javascript polyfill shim
Last synced: 6 days ago
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An ESnext spec-compliant `Array.prototype.groupToMap` shim/polyfill/replacement that works as far down as ES3.
- Host: GitHub
- URL: https://github.com/es-shims/array.prototype.grouptomap
- Owner: es-shims
- License: mit
- Created: 2021-12-14T19:52:10.000Z (almost 4 years ago)
- Default Branch: main
- Last Pushed: 2024-02-10T21:43:38.000Z (over 1 year ago)
- Last Synced: 2025-09-29T06:43:07.434Z (7 days ago)
- Topics: array, ecmascript, group, groupby, groupbytomap, grouping, javascript, polyfill, shim
- Language: JavaScript
- Homepage:
- Size: 58.6 KB
- Stars: 9
- Watchers: 4
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Funding: .github/FUNDING.yml
- License: LICENSE
Awesome Lists containing this project
README
# array.prototype.groupToMap [![Version Badge][npm-version-svg]][package-url]
[![dependency status][deps-svg]][deps-url]
[![dev dependency status][dev-deps-svg]][dev-deps-url]
[![License][license-image]][license-url]
[![Downloads][downloads-image]][downloads-url]
[![npm badge][npm-badge-png]][package-url]
An ESnext spec-compliant `Array.prototype.groupToMap` shim/polyfill/replacement that works as far down as ES3.
This package implements the [es-shim API](https://github.com/es-shims/api) interface. It works in an ES3-supported environment and complies with the proposed [spec](https://tc39.github.io/proposal-array-grouping/).
Because `Array.prototype.groupToMap` depends on a receiver (the `this` value), the main export takes the array to operate on as the first argument.
## Getting started
```sh
npm install --save array.prototype.grouptomap
```
## Usage/Examples
```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));
```
## Tests
Simply clone the repo, `npm install`, 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