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