webpack/lib/container/RemoteRuntimeModule.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";

const RuntimeGlobals = require("../RuntimeGlobals");
const RuntimeModule = require("../RuntimeModule");
const Template = require("../Template");
const { compareModulesByIdentifier } = require("../util/comparators");

/** @import Chunk, { ChunkId } from "../Chunk" */
/** @import ChunkGraph, { ModuleId } from "../ChunkGraph" */
/** @import Compilation from "../Compilation" */
/** @import RemoteModule from "./RemoteModule" */

class RemoteRuntimeModule extends RuntimeModule {
	constructor() {
		super("remotes loading");
	}

	/**
	 * Generates runtime code for this runtime module.
	 * @returns {string | null} runtime code
	 */
	generate() {
		const compilation = /** @type {Compilation} */ (this.compilation);
		const chunkGraph = /** @type {ChunkGraph} */ (this.chunkGraph);
		const { runtimeTemplate, moduleGraph } = compilation;
		/** @type {Record<ChunkId, ModuleId[]>} */
		const chunkToRemotesMapping = {};
		/** @type {Record<ModuleId, [string, string, ModuleId]>} */
		const idToExternalAndNameMapping = {};
		for (const chunk of /** @type {Chunk} */ (
			this.chunk
		).getAllReferencedChunks()) {
			// ordered explicitly: an unordered read reflects whichever comparator
			// last sorted the chunk's modules, which is not ours to depend on
			const modules = chunkGraph.getOrderedChunkModulesIterableBySourceType(
				chunk,
				"remote",
				compareModulesByIdentifier
			);
			if (!modules) continue;
			/** @type {ModuleId[]} */
			const remotes = (chunkToRemotesMapping[
				/** @type {ChunkId} */
				(chunk.id)
			] = []);
			for (const m of modules) {
				const module = /** @type {RemoteModule} */ (m);
				const name = module.internalRequest;
				const id = /** @type {ModuleId} */ (chunkGraph.getModuleId(module));
				const shareScope = module.shareScope;
				const dep = module.dependencies[0];
				const externalModule = moduleGraph.getModule(dep);
				const externalModuleId =
					/** @type {ModuleId} */
					(externalModule && chunkGraph.getModuleId(externalModule));
				remotes.push(id);
				idToExternalAndNameMapping[id] = [shareScope, name, externalModuleId];
			}
		}
		const cst = runtimeTemplate.renderConst();
		const lt = runtimeTemplate.renderLet();
		return Template.asString([
			`${cst} chunkMapping = ${JSON.stringify(
				chunkToRemotesMapping,
				null,
				"\t"
			)};`,
			`${cst} idToExternalAndNameMapping = ${JSON.stringify(
				idToExternalAndNameMapping,
				null,
				"\t"
			)};`,
			`${
				RuntimeGlobals.ensureChunkHandlers
			}.remotes = ${runtimeTemplate.basicFunction("chunkId, promises", [
				`if(${RuntimeGlobals.hasOwnProperty}(chunkMapping, chunkId)) {`,
				Template.indent([
					`chunkMapping[chunkId].forEach(${runtimeTemplate.basicFunction("id", [
						`${lt} getScope = ${RuntimeGlobals.currentRemoteGetScope};`,
						"if(!getScope) getScope = [];",
						`${cst} data = idToExternalAndNameMapping[id];`,
						"if(getScope.indexOf(data) >= 0) return;",
						"getScope.push(data);",
						"if(data.p) return promises.push(data.p);",
						`${cst} onError = ${runtimeTemplate.basicFunction("error", [
							'if(!error) error = new Error("Container missing");',
							'if(typeof error.message === "string")',
							Template.indent(
								"error.message += '\\nwhile loading \"' + data[1] + '\" from ' + data[2];"
							),
							`${
								RuntimeGlobals.moduleFactories
							}[id] = ${runtimeTemplate.basicFunction("", ["throw error;"])}`,
							"data.p = 0;"
						])};`,
						`${cst} handleFunction = ${runtimeTemplate.basicFunction(
							"fn, arg1, arg2, d, next, first",
							[
								"try {",
								Template.indent([
									`${cst} promise = fn(arg1, arg2);`,
									`if(${runtimeTemplate.optionalChaining("promise", "then")}) {`,
									Template.indent([
										`${cst} p = promise.then(${runtimeTemplate.returningFunction(
											"next(result, d)",
											"result"
										)}, onError);`,
										"if(first) promises.push(data.p = p); else return p;"
									]),
									"} else {",
									Template.indent(["return next(promise, d, first);"]),
									"}"
								]),
								"} catch(error) {",
								Template.indent(["onError(error);"]),
								"}"
							]
						)}`,
						`${cst} onExternal = ${runtimeTemplate.returningFunction(
							`external ? handleFunction(${RuntimeGlobals.initializeSharing}, data[0], 0, external, onInitialized, first) : onError()`,
							"external, _, first"
						)};`,
						`${cst} onInitialized = ${runtimeTemplate.returningFunction(
							"handleFunction(external.get, data[1], getScope, 0, onFactory, first)",
							"_, external, first"
						)};`,
						`${cst} onFactory = ${runtimeTemplate.basicFunction("factory", [
							"data.p = 1;",
							`${
								RuntimeGlobals.moduleFactories
							}[id] = ${runtimeTemplate.basicFunction("module", [
								"module.exports = factory();"
							])}`
						])};`,
						`handleFunction(${RuntimeGlobals.require}, data[2], 0, 0, onExternal, 1);`
					])});`
				]),
				"}"
			])}`
		]);
	}
}

module.exports = RemoteRuntimeModule;