webpack/lib/javascript/StartupHelpers.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";

const Entrypoint = require("../Entrypoint");
const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");
const { isSubset } = require("../util/SetHelpers");
const { chunkHasJs } = require("./JavascriptModulesPlugin");

/** @typedef {import("../util/Hash")} Hash */
/** @typedef {import("../Chunk")} Chunk */
/** @typedef {import("../Compilation")} Compilation */
/** @typedef {import("../ChunkGraph")} ChunkGraph */
/** @typedef {import("../ChunkGroup")} ChunkGroup */
/** @typedef {import("../RuntimeTemplate")} RuntimeTemplate */
/** @typedef {(string|number)[]} EntryItem */

// TODO move to this file to ../javascript/ChunkHelpers.js

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

const EXPORT_PREFIX = "var __webpack_exports__ = ";

/**
 * @param {ChunkGraph} chunkGraph chunkGraph
 * @param {RuntimeTemplate} runtimeTemplate runtimeTemplate
 * @param {import("../ChunkGraph").EntryModuleWithChunkGroup[]} entries entries
 * @param {Chunk} chunk chunk
 * @param {boolean} passive true: passive startup with on chunks loaded
 * @returns {string} runtime code
 */
exports.generateEntryStartup = (
	chunkGraph,
	runtimeTemplate,
	entries,
	chunk,
	passive
) => {
	/** @type {string[]} */
	const runtime = [
		`var __webpack_exec__ = ${runtimeTemplate.returningFunction(
			`__webpack_require__(${RuntimeGlobals.entryModuleId} = moduleId)`,
			"moduleId"
		)}`
	];

	const runModule = id => {
		return `__webpack_exec__(${JSON.stringify(id)})`;
	};
	const outputCombination = (chunks, moduleIds, final) => {
		if (chunks.size === 0) {
			runtime.push(
				`${final ? EXPORT_PREFIX : ""}(${moduleIds.map(runModule).join(", ")});`
			);
		} else {
			const fn = runtimeTemplate.returningFunction(
				moduleIds.map(runModule).join(", ")
			);
			runtime.push(
				`${final && !passive ? EXPORT_PREFIX : ""}${
					passive
						? RuntimeGlobals.onChunksLoaded
						: RuntimeGlobals.startupEntrypoint
				}(0, ${JSON.stringify(Array.from(chunks, c => c.id))}, ${fn});`
			);
			if (final && passive) {
				runtime.push(`${EXPORT_PREFIX}${RuntimeGlobals.onChunksLoaded}();`);
			}
		}
	};

	let currentChunks = undefined;
	let currentModuleIds = undefined;

	for (const [module, entrypoint] of entries) {
		const runtimeChunk = entrypoint.getRuntimeChunk();
		const moduleId = chunkGraph.getModuleId(module);
		const chunks = getAllChunks(entrypoint, chunk, runtimeChunk);
		if (
			currentChunks &&
			currentChunks.size === chunks.size &&
			isSubset(currentChunks, chunks)
		) {
			currentModuleIds.push(moduleId);
		} else {
			if (currentChunks) {
				outputCombination(currentChunks, currentModuleIds);
			}
			currentChunks = chunks;
			currentModuleIds = [moduleId];
		}
	}

	// output current modules with export prefix
	if (currentChunks) {
		outputCombination(currentChunks, currentModuleIds, true);
	}
	runtime.push("");
	return Template.asString(runtime);
};

/**
 * @param {Hash} hash the hash to update
 * @param {ChunkGraph} chunkGraph chunkGraph
 * @param {import("../ChunkGraph").EntryModuleWithChunkGroup[]} entries entries
 * @param {Chunk} chunk chunk
 * @returns {void}
 */
exports.updateHashForEntryStartup = (hash, chunkGraph, entries, chunk) => {
	for (const [module, entrypoint] of entries) {
		const runtimeChunk = entrypoint.getRuntimeChunk();
		const moduleId = chunkGraph.getModuleId(module);
		hash.update(`${moduleId}`);
		for (const c of getAllChunks(entrypoint, chunk, runtimeChunk))
			hash.update(`${c.id}`);
	}
};

/**
 * @param {Chunk} chunk the chunk
 * @param {ChunkGraph} chunkGraph the chunk graph
 * @returns {Set<number | string>} initially fulfilled chunk ids
 */
exports.getInitialChunkIds = (chunk, chunkGraph) => {
	const initialChunkIds = new Set(chunk.ids);
	for (const c of chunk.getAllInitialChunks()) {
		if (c === chunk || chunkHasJs(c, chunkGraph)) continue;
		for (const id of c.ids) initialChunkIds.add(id);
	}
	return initialChunkIds;
};