https://github.com/ljharb/es-get-iterator

Get an iterator for any JS language value. Works robustly across all environments, all versions.
https://github.com/ljharb/es-get-iterator

Last synced: 3 days ago
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Get an iterator for any JS language value. Works robustly across all environments, all versions.

• Host: GitHub
• URL: https://github.com/ljharb/es-get-iterator
• Owner: ljharb
• License: mit
• Created: 2019-11-22T04:14:42.000Z (almost 5 years ago)
• Default Branch: main
• Last Pushed: 2024-06-15T20:01:56.000Z (5 months ago)
• Last Synced: 2024-10-29T14:24:48.024Z (5 days ago)
• Language: JavaScript
• Homepage:
• Size: 98.6 KB
• Stars: 13
• Watchers: 3
• Forks: 5
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • Funding: .github/FUNDING.yml
  • License: LICENSE

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README

        
# es-get-iterator [![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]

Get an iterator for any JS language value. Works robustly across all environments, all versions.

In modern engines, `value[Symbol.iterator]()` is sufficient to produce an iterator (an object with a `.next` method) for that object. However, older engines:

 - may lack `Symbol` support altogether

 - may have `Symbol.iterator` but not implement it on everything it should, like arguments objects

 - may have `Map` and `Set`, but a non-standard name for the iterator-producing method (`.iterator` or `['@@iterator']`, eg)

 - may be old versions of Firefox that produce values until they throw a StopIteration exception, rather than having iteration result objects

 - may be polyfilled/shimmed/shammed, with `es6-shim` or `core-js` or similar

This library attempts to provide an abstraction over all that complexity!

In node v13+, `exports` is used to provide a lean implementation that lacks all the complexity described above, in combination with the `browser` field so that bundlers will pick up the proper implementation.

## Targeting browsers with Symbol support

If you are targeting browsers that definitely all have Symbol support, then you can configure your bundler to replace `require('has-symbols')()` with a literal `true`, which should allow dead code elimination to reduce the size of the bundled code.

### With `@rollup/plugin-replace`

```js

// rollup.config.js

import replace from '@rollup/plugin-replace';

export default {

	...

	plugins: [

		replace({

			"require('has-symbols')()": 'true',

			delimiters: ['', '']

		})

	]

};

```

## Example

```js

var getIterator = require('es-get-iterator');

var assert = require('assert');

var iterator = getIterator('a 💩');

assert.deepEqual(

	[iterator.next(), iterator.next(), iterator.next(), iterator.next()],

	[{ done: false, value: 'a' }, { done: false, value: ' ' }, { done: false, value: '💩' }, { done: true, value: undefined }]

);

var iterator = getIterator([1, 2]);

assert.deepEqual(

	[iterator.next(), iterator.next(), iterator.next()],

	[{ done: false, value: 1 }, { done: false, value: 2 }, { done: true, value: undefined }]

);

var iterator = getIterator(new Set([1, 2]));

assert.deepEqual(

	[iterator.next(), iterator.next(), iterator.next()],

	[{ done: false, value: 1 }, { done: false, value: 2 }, { done: true, value: undefined }]

);

var iterator = getIterator(new Map([[1, 2], [3, 4]]));

assert.deepEqual(

	[iterator.next(), iterator.next(), iterator.next()],

	[{ done: false, value: [1, 2] }, { done: false, value: [3, 4] }, { done: true, value: undefined }]

);

```

## Tests

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

[package-url]: https://npmjs.org/package/es-get-iterator

[npm-version-svg]: https://versionbadg.es/ljharb/es-get-iterator.svg

[deps-svg]: https://david-dm.org/ljharb/es-get-iterator.svg

[deps-url]: https://david-dm.org/ljharb/es-get-iterator

[dev-deps-svg]: https://david-dm.org/ljharb/es-get-iterator/dev-status.svg

[dev-deps-url]: https://david-dm.org/ljharb/es-get-iterator#info=devDependencies

[npm-badge-png]: https://nodei.co/npm/es-get-iterator.png?downloads=true&stars=true

[license-image]: https://img.shields.io/npm/l/es-get-iterator.svg

[license-url]: LICENSE

[downloads-image]: https://img.shields.io/npm/dm/es-get-iterator.svg

[downloads-url]: https://npm-stat.com/charts.html?package=es-get-iterator