webpack/lib/runtime/StartupEntrypointRuntimeModule.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
*/

"use strict";

const RuntimeGlobals = require("../RuntimeGlobals");
const RuntimeModule = require("../RuntimeModule");

/** @typedef {import("../Compilation")} Compilation */
/** @typedef {import("../MainTemplate")} MainTemplate */

class StartupEntrypointRuntimeModule extends RuntimeModule {
	/**
	 * @param {boolean} asyncChunkLoading use async chunk loading
	 */
	constructor(asyncChunkLoading) {
		super("startup entrypoint");
		this.asyncChunkLoading = asyncChunkLoading;
	}

	/**
	 * @returns {string | null} runtime code
	 */
	generate() {
		const compilation = /** @type {Compilation} */ (this.compilation);
		const { runtimeTemplate } = compilation;
		return `${
			RuntimeGlobals.startupEntrypoint
		} = ${runtimeTemplate.basicFunction("result, chunkIds, fn", [
			"// arguments: chunkIds, moduleId are deprecated",
			"var moduleId = chunkIds;",
			`if(!fn) chunkIds = result, fn = ${runtimeTemplate.returningFunction(
				`${RuntimeGlobals.require}(${RuntimeGlobals.entryModuleId} = moduleId)`
			)};`,
			...(this.asyncChunkLoading
				? [
						`return Promise.all(chunkIds.map(${RuntimeGlobals.ensureChunk}, ${
							RuntimeGlobals.require
						})).then(${runtimeTemplate.basicFunction("", [
							"var r = fn();",
							"return r === undefined ? result : r;"
						])})`
					]
				: [
						`chunkIds.map(${RuntimeGlobals.ensureChunk}, ${RuntimeGlobals.require})`,
						"var r = fn();",
						"return r === undefined ? result : r;"
					])
		])}`;
	}
}

module.exports = StartupEntrypointRuntimeModule;