webpack/lib/runtime/ConstructRequireRuntimeModule.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 Template = require("../Template");
const HelperRuntimeModule = require("./HelperRuntimeModule");

/** @import Compilation from "../Compilation" */

class ConstructRequireRuntimeModule extends HelperRuntimeModule {
	constructor() {
		super("construct require");
	}

	/**
	 * Returns true, if the runtime module should get it's own scope.
	 * When false, `generate()` must emit complete statements ending with `;`
	 * so a following runtime IIFE is not parsed as a call (ASI).
	 * @returns {boolean} true, if the runtime module should get it's own scope
	 */
	shouldIsolate() {
		return false;
	}

	/**
	 * Generates runtime code for this runtime module.
	 * @returns {string | null} runtime code
	 */
	generate() {
		const compilation = /** @type {Compilation} */ (this.compilation);
		const { runtimeTemplate } = compilation;
		const fn = RuntimeGlobals.constructRequire;
		return Template.asString([
			"// `new require(id)` invokes the require function as a constructor, so a",
			"// primitive module.exports is discarded in favor of the freshly created",
			"// instance, exactly as in Node.js. A concatenated module has no require",
			"// call left, so apply that rule to its exports value instead.",
			`${fn} = ${runtimeTemplate.basicFunction("exports", [
				`${runtimeTemplate.renderConst()} isObject =`,
				Template.indent(
					'exports !== null && (typeof exports === "object" || typeof exports === "function");'
				),
				`return isObject ? exports : Object.create(${RuntimeGlobals.require}.prototype);`
			])};`
		]);
	}
}

module.exports = ConstructRequireRuntimeModule;