zip (for Iterators)

Lazily combines several iterators into a single iterator of tuples.

const pairs = zip(source1, source2);

Usage

zip(...sources)

Use zip when you want to walk several sequences in lockstep — for example, pairing indices with values or names with scores. Elements at matching positions are combined into tuples, and iteration stops as soon as the shortest source is exhausted. Stopping at the shortest source (rather than padding to the longest, as the array zip does) is what makes it safe to combine finite and infinite iterators. When iteration ends — because a source ran out or the consumer stopped early — every source is closed via its return method.

import { zip } from 'es-toolkit/iterator';
// Returns: [[1, 'a'], [2, 'b']]
// Number an arbitrary sequence with an unbounded counter.
import { range } from 'es-toolkit/iterator';

// Pair elements at matching positions.
zip([1, 2, 3].values(), ['a', 'b', 'c'].values()).toArray();
// Returns: [[1, 'a'], [2, 'b'], [3, 'c']]

// The shortest source bounds the result.
zip([1, 2, 3].values(), ['a', 'b'].values()).toArray();

zip(range(0, Infinity), ['a', 'b', 'c'].values()).toArray();
// Returns: [[0, 'a'], [1, 'b'], [2, 'c']]

Parameters

• sources (Array<Iterator<unknown>>): The iterators to zip together.

Returns

(IteratorObject<[...], undefined>): A lazy iterator over tuples of the paired elements, typed after the sources. It carries every native iterator helper (map, take, toArray, ...) for further chaining.

zip(other) with pipe

When composing transformations with pipe, import the curried form from es-toolkit/fp/iterator. It takes one other iterator and pairs the piped iterator's elements with it.

import { pipe } from 'es-toolkit/fp';
import { toArray, zip } from 'es-toolkit/fp/iterator';

pipe([1, 2, 3].values(), zip(['a', 'b', 'c'].values()), toArray());
// Returns: [[1, 'a'], [2, 'b'], [3, 'c']]