webpack/lib/javascript/ChunkHelpers.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";

/** @import Chunk from "../graph/Chunk" */
/** @import ChunkGraph from "../graph/ChunkGraph" */
/** @import Entrypoint from "../graph/Entrypoint" */
/** @import Module from "../module/Module" */
/** @import Hash from "../util/Hash" */
/** @import { ChunkHashContext } from "../Compilation" */

/**
 * Returns chunks.
 * @param {Entrypoint} entrypoint a chunk group
 * @param {(Chunk | null)=} excludedChunk1 current chunk which is excluded
 * @param {(Chunk | null)=} excludedChunk2 runtime chunk which is excluded
 * @returns {Set<Chunk>} chunks
 */
const getAllChunks = (entrypoint, excludedChunk1, excludedChunk2) => {
	/** @type {Set<Entrypoint>} */
	const queue = new Set([entrypoint]);
	/** @type {Set<Entrypoint>} */
	const groups = new Set();
	for (const group of queue) {
		if (group !== entrypoint) {
			groups.add(group);
		}
		for (const parent of group.parentsIterable) {
			if (parent.isEntrypoint()) queue.add(parent);
		}
	}
	groups.add(entrypoint);

	/** @type {Set<Chunk>} */
	const chunks = new Set();
	for (const group of groups) {
		for (const chunk of group.chunks) {
			if (chunk === excludedChunk1) continue;
			if (chunk === excludedChunk2) continue;
			chunks.add(chunk);
		}
	}
	return chunks;
};

/**
 * Returns } Object containing chunk entries and runtime chunk.
 * @param {Chunk} chunk The chunk to get information for
 * @param {ChunkGraph} chunkGraph The chunk graph containing the chunk
 * @returns {{ entries: [Module, Entrypoint | undefined][], runtimeChunk: Chunk | null }} Object containing chunk entries and runtime chunk
 */
function getChunkInfo(chunk, chunkGraph) {
	const entries = [
		...chunkGraph.getChunkEntryModulesWithChunkGroupIterable(chunk)
	];
	const runtimeChunk =
		entries.length > 0
			? /** @type {Entrypoint[][]} */
				(entries)[0][1].getRuntimeChunk()
			: null;

	return {
		entries,
		runtimeChunk
	};
}

/**
 * Creates a chunk hash handler
 * @param {string} name The name of the chunk
 * @returns {(chunk: Chunk, hash: Hash, { chunkGraph }: ChunkHashContext) => void} The chunk hash handler
 */
function createChunkHashHandler(name) {
	/**
	 * Processes the provided chunk.
	 * @param {Chunk} chunk The chunk to get information for
	 * @param {Hash} hash The hash to update
	 * @param {ChunkHashContext} chunkHashContext The chunk hash context
	 * @returns {void}
	 */
	return (chunk, hash, { chunkGraph }) => {
		if (chunk.hasRuntime()) return;
		const { entries, runtimeChunk } = getChunkInfo(chunk, chunkGraph);
		hash.update(name);
		hash.update("1");
		if (runtimeChunk && runtimeChunk.hash) {
			// WHY: any change to the runtime chunk must move this hash, and its
			// internal implementation is not ours to depend on or inspect — the import
			// names its hashed filename:
			// import __webpack_require__ from "./runtime-main.e9400aee33633a3973bd.js";
			// https://github.com/webpack/webpack/issues/19439
			hash.update(runtimeChunk.hash);
		}

		const { updateHashForEntryStartup } = require("./StartupHelpers");

		updateHashForEntryStartup(hash, chunkGraph, entries, chunk);
	};
}

module.exports.getAllChunks = getAllChunks;
module.exports.createChunkHashHandler = createChunkHashHandler;
module.exports.getChunkInfo = getChunkInfo;