https://github.com/ljharb/iterate-value

Iterate any iterable JS value. Works robustly in all environments, all versions.
https://github.com/ljharb/iterate-value

iterate iteration iterator javascript value value-iteration

Last synced: 11 days ago
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Iterate any iterable JS value. Works robustly in all environments, all versions.

• Host: GitHub
• URL: https://github.com/ljharb/iterate-value
• Owner: ljharb
• License: mit
• Created: 2019-11-21T07:24:17.000Z (almost 5 years ago)
• Default Branch: main
• Last Pushed: 2022-10-27T04:59:40.000Z (about 2 years ago)
• Last Synced: 2024-11-02T09:21:59.970Z (18 days ago)
• Topics: iterate, iteration, iterator, javascript, value, value-iteration
• Language: JavaScript
• Homepage:
• Size: 54.7 KB
• Stars: 3
• Watchers: 3
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • Funding: .github/FUNDING.yml
  • License: LICENSE

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README

        
# iterate-value [![Version Badge][npm-version-svg]][package-url]

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Iterate any iterable JS value. Works robustly in all environments, all versions.

In modern engines, `[...value]` or `Array.from(value)` or `for (const item of value) { }` are sufficient to iterate an iterable value (an object with a `Symbol.iterator` method). However, older engines:

 - may lack `Symbol`, array spread, or `for..of` 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) and no syntax to support it

 - 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!

If called with a single value, it will return an array of the yielded values. If also called with a callback function, it will instead call that callback once for each yielded value.

In node v13+, `exports` is used by the `es-get-iterator` dependency 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.

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.

## Example

```js

var iterate = require('iterate-value');

var assert = require('assert');

assert.deepEqual(iterate('a 💩'), ['a', ' ', '💩']);

assert.deepEqual(iterate([1, 2]), [1, 2]);

assert.deepEqual(iterate(new Set([1, 2])), [1, 2]);

assert.deepEqual(iterate(new Map([[1, 2], [3, 4]])), [[1, 2], [3, 4]]);

function assertWithCallback(iterable, expected) {

	var values = [];

	var callback = function (x) { values.push(x); };

	iterate(iterable, callback);

	assert.deepEqual(values, expected);

}

assertWithCallback('a 💩', ['a', ' ', '💩']);

assertWithCallback([1, 2], [1, 2]);

assertWithCallback(new Set([1, 2]), [1, 2]);

assertWithCallback(new Map([[1, 2], [3, 4]]), [[1, 2], [3, 4]]);

```

## Tests

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

[package-url]: https://npmjs.org/package/iterate-value

[npm-version-svg]: https://versionbadg.es/ljharb/iterate-value.svg

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[dev-deps-url]: https://david-dm.org/ljharb/iterate-value#info=devDependencies

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[license-url]: LICENSE

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[codecov-url]: https://app.codecov.io/gh/ljharb/iterate-value/

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[actions-url]: https://github.com/ljharb/iterate-value/actions