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");

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

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

	/**
	 * 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 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 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() {
		// We avoid isolating this to have better backward-compat
		return false;
	}
}

module.exports = CompatRuntimeModule;