src/compress.js

import {_zip2} from '@iterable-iterator/zip';

/**
 * Filters the first input iterable according to truthy and flasy values from a
 * second input iterable. The ith element of the first input iterable is output
 * if and only if the ith element of the second input iterable is truthy.
 *
 * @param {Iterable} iterable - The first input iterable to filter.
 * @param {Iterable} selector - The second input iterable containing the truthy and falsy
 * values.
 * @returns {Iterator}
 */
export default function* compress(iterable, selector) {
	for (const [take, item] of _zip2(selector, iterable)) {
		if (take) {
			yield item;
		}
	}
}