Method apply

lib/optimize/SplitChunksPlugin.js:880–1883

* Applies the plugin by registering its hooks on the compiler. * @param {Compiler} compiler the compiler instance * @returns {void}

(compiler)

	 * @returns {void}
	 */
	apply(compiler) {
		const cachedMakePathsRelative = makePathsRelative.bindContextCache(
			compiler.context,
			compiler.root
		);
		compiler.hooks.thisCompilation.tap(PLUGIN_NAME, (compilation) => {
			const logger = compilation.getLogger(`webpack.${PLUGIN_NAME}`);
			let alreadyOptimized = false;
			compilation.hooks.unseal.tap(PLUGIN_NAME, () => {
				alreadyOptimized = false;
			});
			compilation.hooks.optimizeChunks.tap(
				{
					name: PLUGIN_NAME,
					stage: STAGE_ADVANCED
				},
				(chunks) => {
					if (alreadyOptimized) return;
					alreadyOptimized = true;
					logger.time("prepare");
					const chunkGraph = compilation.chunkGraph;
					const moduleGraph = compilation.moduleGraph;
					// Give each selected chunk an index (to create strings from chunks)
					/** @type {Map<Chunk, bigint>} */
					const chunkIndexMap = new Map();
					const ZERO = BigInt("0");
					const ONE = BigInt("1");
					const START = ONE << BigInt("31");
					let index = START;
					for (const chunk of chunks) {
						chunkIndexMap.set(
							chunk,
							index | BigInt((Math.random() * 0x7fffffff) | 0)
						);
						index <<= ONE;
					}
					/**
					 * Returns key of the chunks.
					 * @param {Iterable<Chunk, undefined, undefined>} chunks list of chunks
					 * @returns {bigint | Chunk} key of the chunks
					 */
					const getKey = (chunks) => {
						const iterator = chunks[Symbol.iterator]();
						let result = iterator.next();
						if (result.done) return ZERO;
						const first = result.value;
						result = iterator.next();
						if (result.done) return first;
						let key =
							/** @type {bigint} */ (chunkIndexMap.get(first)) |
							/** @type {bigint} */ (chunkIndexMap.get(result.value));
						while (!(result = iterator.next()).done) {
							const raw = chunkIndexMap.get(result.value);
							key ^= /** @type {bigint} */ (raw);
						}
						return key;
					};
					/**