webpack/lib/node/RequireChunkLoadingRuntimeModule.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
*/

"use strict";

const RuntimeGlobals = require("../RuntimeGlobals");
const RuntimeModule = require("../RuntimeModule");
const Template = require("../Template");
const {
	chunkHasJs,
	getChunkFilenameTemplate
} = require("../javascript/JavascriptModulesPlugin");
const { getInitialChunkIds } = require("../javascript/StartupHelpers");
const compileBooleanMatcher = require("../util/compileBooleanMatcher");
const { getUndoPath } = require("../util/identifier");

class RequireChunkLoadingRuntimeModule extends RuntimeModule {
	constructor(runtimeRequirements) {
		super("require chunk loading", RuntimeModule.STAGE_ATTACH);
		this.runtimeRequirements = runtimeRequirements;
	}

	/**
	 * @returns {string} runtime code
	 */
	generate() {
		const { chunkGraph, chunk } = this;
		const { runtimeTemplate } = this.compilation;
		const fn = RuntimeGlobals.ensureChunkHandlers;
		const withBaseURI = this.runtimeRequirements.has(RuntimeGlobals.baseURI);
		const withExternalInstallChunk = this.runtimeRequirements.has(
			RuntimeGlobals.externalInstallChunk
		);
		const withOnChunkLoad = this.runtimeRequirements.has(
			RuntimeGlobals.onChunksLoaded
		);
		const withLoading = this.runtimeRequirements.has(
			RuntimeGlobals.ensureChunkHandlers
		);
		const withHmr = this.runtimeRequirements.has(
			RuntimeGlobals.hmrDownloadUpdateHandlers
		);
		const withHmrManifest = this.runtimeRequirements.has(
			RuntimeGlobals.hmrDownloadManifest
		);
		const conditionMap = chunkGraph.getChunkConditionMap(chunk, chunkHasJs);
		const hasJsMatcher = compileBooleanMatcher(conditionMap);
		const initialChunkIds = getInitialChunkIds(chunk, chunkGraph);

		const outputName = this.compilation.getPath(
			getChunkFilenameTemplate(chunk, this.compilation.outputOptions),
			{
				chunk,
				contentHashType: "javascript"
			}
		);
		const rootOutputDir = getUndoPath(
			outputName,
			this.compilation.outputOptions.path,
			true
		);

		const stateExpression = withHmr
			? `${RuntimeGlobals.hmrRuntimeStatePrefix}_require`
			: undefined;

		return Template.asString([
			withBaseURI
				? Template.asString([
						`${RuntimeGlobals.baseURI} = require("url").pathToFileURL(${
							rootOutputDir !== "./"
								? `__dirname + ${JSON.stringify("/" + rootOutputDir)}`
								: "__filename"
						});`
				  ])
				: "// no baseURI",
			"",
			"// object to store loaded chunks",
			'// "1" means "loaded", otherwise not loaded yet',
			`var installedChunks = ${
				stateExpression ? `${stateExpression} = ${stateExpression} || ` : ""
			}{`,
			Template.indent(
				Array.from(initialChunkIds, id => `${JSON.stringify(id)}: 1`).join(
					",\n"
				)
			),
			"};",
			"",
			withOnChunkLoad
				? `${
						RuntimeGlobals.onChunksLoaded
				  }.require = ${runtimeTemplate.returningFunction(
						"installedChunks[chunkId]",
						"chunkId"
				  )};`
				: "// no on chunks loaded",
			"",
			withLoading || withExternalInstallChunk
				? `var installChunk = ${runtimeTemplate.basicFunction("chunk", [
						"var moreModules = chunk.modules, chunkIds = chunk.ids, runtime = chunk.runtime;",
						"for(var moduleId in moreModules) {",
						Template.indent([
							`if(${RuntimeGlobals.hasOwnProperty}(moreModules, moduleId)) {`,
							Template.indent([
								`${RuntimeGlobals.moduleFactories}[moduleId] = moreModules[moduleId];`
							]),
							"}"
						]),
						"}",
						`if(runtime) runtime(__webpack_require__);`,
						"for(var i = 0; i < chunkIds.length; i++)",
						Template.indent("installedChunks[chunkIds[i]] = 1;"),
						withOnChunkLoad ? `${RuntimeGlobals.onChunksLoaded}();` : ""
				  ])};`
				: "// no chunk install function needed",
			"",
			withLoading
				? Template.asString([
						"// require() chunk loading for javascript",
						`${fn}.require = ${runtimeTemplate.basicFunction(
							"chunkId, promises",
							hasJsMatcher !== false
								? [
										'// "1" is the signal for "already loaded"',
										"if(!installedChunks[chunkId]) {",
										Template.indent([
											hasJsMatcher === true
												? "if(true) { // all chunks have JS"
												: `if(${hasJsMatcher("chunkId")}) {`,
											Template.indent([
												`installChunk(require(${JSON.stringify(
													rootOutputDir
												)} + ${
													RuntimeGlobals.getChunkScriptFilename
												}(chunkId)));`
											]),
											"} else installedChunks[chunkId] = 1;",
											""
										]),
										"}"
								  ]
								: "installedChunks[chunkId] = 1;"
						)};`
				  ])
				: "// no chunk loading",
			"",
			withExternalInstallChunk
				? Template.asString([
						"module.exports = __webpack_require__;",
						`${RuntimeGlobals.externalInstallChunk} = installChunk;`
				  ])
				: "// no external install chunk",
			"",
			withHmr
				? Template.asString([
						"function loadUpdateChunk(chunkId, updatedModulesList) {",
						Template.indent([
							`var update = require(${JSON.stringify(rootOutputDir)} + ${
								RuntimeGlobals.getChunkUpdateScriptFilename
							}(chunkId));`,
							"var updatedModules = update.modules;",
							"var runtime = update.runtime;",
							"for(var moduleId in updatedModules) {",
							Template.indent([
								`if(${RuntimeGlobals.hasOwnProperty}(updatedModules, moduleId)) {`,
								Template.indent([
									`currentUpdate[moduleId] = updatedModules[moduleId];`,
									"if(updatedModulesList) updatedModulesList.push(moduleId);"
								]),
								"}"
							]),
							"}",
							"if(runtime) currentUpdateRuntime.push(runtime);"
						]),
						"}",
						"",
						Template.getFunctionContent(
							require("../hmr/JavascriptHotModuleReplacement.runtime.js")
						)
							.replace(/\$key\$/g, "require")
							.replace(/\$installedChunks\$/g, "installedChunks")
							.replace(/\$loadUpdateChunk\$/g, "loadUpdateChunk")
							.replace(/\$moduleCache\$/g, RuntimeGlobals.moduleCache)
							.replace(/\$moduleFactories\$/g, RuntimeGlobals.moduleFactories)
							.replace(
								/\$ensureChunkHandlers\$/g,
								RuntimeGlobals.ensureChunkHandlers
							)
							.replace(/\$hasOwnProperty\$/g, RuntimeGlobals.hasOwnProperty)
							.replace(/\$hmrModuleData\$/g, RuntimeGlobals.hmrModuleData)
							.replace(
								/\$hmrDownloadUpdateHandlers\$/g,
								RuntimeGlobals.hmrDownloadUpdateHandlers
							)
							.replace(
								/\$hmrInvalidateModuleHandlers\$/g,
								RuntimeGlobals.hmrInvalidateModuleHandlers
							)
				  ])
				: "// no HMR",
			"",
			withHmrManifest
				? Template.asString([
						`${RuntimeGlobals.hmrDownloadManifest} = function() {`,
						Template.indent([
							"return Promise.resolve().then(function() {",
							Template.indent([
								`return require(${JSON.stringify(rootOutputDir)} + ${
									RuntimeGlobals.getUpdateManifestFilename
								}());`
							]),
							"})['catch'](function(err) { if(err.code !== 'MODULE_NOT_FOUND') throw err; });"
						]),
						"}"
				  ])
				: "// no HMR manifest"
		]);
	}
}

module.exports = RequireChunkLoadingRuntimeModule;