iterate-iterator

iterate-iterator

Iterate any iterable JS iterator. 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), which includes all builtin iterators. 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 simplifies iterating an iterator object, so no loops are required.

If called with a single iterator, 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.

Example

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

assert.deepEqual(iterate(getIterator('a 💩')), ['a', ' ', '💩']);
assert.deepEqual(iterate(getIterator([1, 2])), [1, 2]);
assert.deepEqual(iterate(getIterator(new Set([1, 2]))), [1, 2]);
assert.deepEqual(iterate(getIterator(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(getIterator('a 💩'), ['a', ' ', '💩']);
assertWithCallback(getIterator([1, 2]), [1, 2]);
assertWithCallback(getIterator(new Set([1, 2])), [1, 2]);
assertWithCallback(getIterator(new Map([[1, 2], [3, 4]])), [[1, 2], [3, 4]]);

Tests

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

Changelog

v1.0.2 - 2021-10-01

Commits

• [Tests] migrate tests to Github Actions 13a9d00
• [meta] do not publish Github Actions workflows 15d4556
• [actions] use node/install instead of node/run; use codecov action a23decd
• [Tests] run nyc on all tests; use tape runner 86adda1
• [Tests] fix tests in IE 8 9c44f28
• [Dev Deps] update eslint, @ljharb/eslint-config, aud, auto-changelog, es-get-iterator, object-inspect, tape 7887af7
• [Dev Deps] update eslint, @ljharb/eslint-config, auto-changelog, object-inspect, tape 21975ca
• [Dev Deps] update eslint, @ljharb/eslint-config, aud, es-get-iterator, object-inspect, tape a42d8cd
• [actions] add "Allow Edits" workflow a23d108
• [readme] remove travis badge dc38174
• [Dev Deps] update @ljharb/eslint-config, es-get-iterator 970e212
• [readme] add actions and codecov badges 1a41785
• [actions] switch Automatic Rebase workflow to pull_request_target event 9e5bcbf
• [Dev Deps] update aud, auto-changelog 63f0b43
• [Dev Deps] update auto-changelog, tape 2186bf5
• [meta] add package.json to "exports" 97a1ac2
• [meta] use prepublishOnly, for npm 7+ b35c088
• [Tests] only audit prod deps 15f9f7c
• [meta] add funding field ab52815
• [Dev Deps] update tape d044397