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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.

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

"use strict";

/** @typedef {import("webpack-sources").Source} Source */

/** @type {WeakMap>} */
const equalityCache = new WeakMap();

/**
 * @param {Source} a a source
 * @param {Source} b another source
 * @returns {boolean} true, when both sources are equal
 */
const _isSourceEqual = (a, b) => {
	// prefer .buffer(), it's called anyway during emit
	/** @type {Buffer|string} */
	let aSource = typeof a.buffer === "function" ? a.buffer() : a.source();
	/** @type {Buffer|string} */
	let bSource = typeof b.buffer === "function" ? b.buffer() : b.source();
	if (aSource === bSource) return true;
	if (typeof aSource === "string" && typeof bSource === "string") return false;
	if (!Buffer.isBuffer(aSource)) aSource = Buffer.from(aSource, "utf-8");
	if (!Buffer.isBuffer(bSource)) bSource = Buffer.from(bSource, "utf-8");
	return aSource.equals(bSource);
};

/**
 * @param {Source} a a source
 * @param {Source} b another source
 * @returns {boolean} true, when both sources are equal
 */
const isSourceEqual = (a, b) => {
	if (a === b) return true;
	const cache1 = equalityCache.get(a);
	if (cache1 !== undefined) {
		const result = cache1.get(b);
		if (result !== undefined) return result;
	}
	const result = _isSourceEqual(a, b);
	if (cache1 !== undefined) {
		cache1.set(b, result);
	} else {
		const map = new WeakMap();
		map.set(b, result);
		equalityCache.set(a, map);
	}
	const cache2 = equalityCache.get(b);
	if (cache2 !== undefined) {
		cache2.set(a, result);
	} else {
		const map = new WeakMap();
		map.set(a, result);
		equalityCache.set(b, map);
	}
	return result;
};
exports.isSourceEqual = isSourceEqual;