webpack/lib/util/IterableHelpers.js

Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

/**
 * Returns last item.
 * @template T
 * @param {Iterable<T>} set a set
 * @returns {T | undefined} last item
 */
const last = (set) => {
	/** @type {T | undefined} */
	let last;
	for (const item of set) last = item;
	return last;
};

/**
 * Returns true, if some items match the filter predicate.
 * @template T
 * @param {Iterable<T>} iterable iterable
 * @param {(value: T) => boolean | null | undefined} filter predicate
 * @returns {boolean} true, if some items match the filter predicate
 */
const someInIterable = (iterable, filter) => {
	for (const item of iterable) {
		if (filter(item)) return true;
	}
	return false;
};

/**
 * Returns count of items.
 * @template T
 * @param {Iterable<T>} iterable an iterable
 * @returns {number} count of items
 */
const countIterable = (iterable) => {
	let i = 0;
	for (const _ of iterable) i++;
	return i;
};

module.exports.countIterable = countIterable;
module.exports.last = last;
module.exports.someInIterable = someInIterable;