webpack/lib/util/ArrayHelpers.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support 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";

exports.equals = (a, b) => {
	if (a.length !== b.length) return false;
	for (let i = 0; i < a.length; i++) {
		if (a[i] !== b[i]) return false;
	}
	return true;
};

/**
 *
 * @param {Array} arr Array of values to be partitioned
 * @param {(value: any) => boolean} fn Partition function which partitions based on truthiness of result.
 * @returns {[Array, Array]} returns the values of `arr` partitioned into two new arrays based on fn predicate.
 */
exports.groupBy = (arr = [], fn) => {
	return arr.reduce(
		(groups, value) => {
			groups[fn(value) ? 0 : 1].push(value);
			return groups;
		},
		[[], []]
	);
};