webpack/lib/runtime/CompatRuntimeModule.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("../Chunk")} Chunk */
/** @typedef {import("../ChunkGraph")} ChunkGraph */
/** @typedef {import("../Compilation")} Compilation */
/** @typedef {import("../MainTemplate")} MainTemplate */

class CompatRuntimeModule extends RuntimeModule {
	constructor() {
		super("compat", RuntimeModule.STAGE_ATTACH);
		this.fullHash = true;
	}

	/**
	 * @returns {string | null} runtime code
	 */
	generate() {
		const compilation = /** @type {Compilation} */ (this.compilation);
		const chunkGraph = /** @type {ChunkGraph} */ (this.chunkGraph);
		const chunk = /** @type {Chunk} */ (this.chunk);
		const {
			runtimeTemplate,
			mainTemplate,
			moduleTemplates,
			dependencyTemplates
		} = compilation;
		const bootstrap = mainTemplate.hooks.bootstrap.call(
			"",
			chunk,
			compilation.hash || "XXXX",
			moduleTemplates.javascript,
			dependencyTemplates
		);
		const localVars = mainTemplate.hooks.localVars.call(
			"",
			chunk,
			compilation.hash || "XXXX"
		);
		const requireExtensions = mainTemplate.hooks.requireExtensions.call(
			"",
			chunk,
			compilation.hash || "XXXX"
		);
		const runtimeRequirements = chunkGraph.getTreeRuntimeRequirements(chunk);
		let requireEnsure = "";
		if (runtimeRequirements.has(RuntimeGlobals.ensureChunk)) {
			const requireEnsureHandler = mainTemplate.hooks.requireEnsure.call(
				"",
				chunk,
				compilation.hash || "XXXX",
				"chunkId"
			);
			if (requireEnsureHandler) {
				requireEnsure = `${
					RuntimeGlobals.ensureChunkHandlers
				}.compat = ${runtimeTemplate.basicFunction(
					"chunkId, promises",
					requireEnsureHandler
				)};`;
			}
		}
		return [bootstrap, localVars, requireEnsure, requireExtensions]
			.filter(Boolean)
			.join("\n");
	}

	/**
	 * @returns {boolean} true, if the runtime module should get it's own scope
	 */
	shouldIsolate() {
		// We avoid isolating this to have better backward-compat
		return false;
	}
}

module.exports = CompatRuntimeModule;