webpack/lib/JavascriptMetaInfoPlugin.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 Sergey Melyukov @smelukov
*/

"use strict";

const {
	JAVASCRIPT_MODULE_TYPE_AUTO,
	JAVASCRIPT_MODULE_TYPE_DYNAMIC,
	JAVASCRIPT_MODULE_TYPE_ESM
} = require("./ModuleTypeConstants");
const InnerGraph = require("./optimize/InnerGraph");

/** @typedef {import("./Compiler")} Compiler */
/** @typedef {import("./Module").BuildInfo} BuildInfo */
/** @typedef {import("./javascript/JavascriptParser")} JavascriptParser */

const PLUGIN_NAME = "JavascriptMetaInfoPlugin";

class JavascriptMetaInfoPlugin {
	/**
	 * Applies the plugin by registering its hooks on the compiler.
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.compilation.tap(
			PLUGIN_NAME,
			(compilation, { normalModuleFactory }) => {
				/**
				 * Handles the hook callback for this code path.
				 * @param {JavascriptParser} parser the parser
				 * @returns {void}
				 */
				const handler = (parser) => {
					parser.hooks.call.for("eval").tap(PLUGIN_NAME, () => {
						const buildInfo =
							/** @type {BuildInfo} */
							(parser.state.module.buildInfo);
						buildInfo.moduleConcatenationBailout = "eval()";
						const currentSymbol = InnerGraph.getTopLevelSymbol(parser.state);
						if (currentSymbol) {
							InnerGraph.addUsage(parser.state, null, currentSymbol);
						} else {
							InnerGraph.bailout(parser.state);
						}
					});
					parser.hooks.finish.tap(PLUGIN_NAME, () => {
						const buildInfo =
							/** @type {BuildInfo} */
							(parser.state.module.buildInfo);
						let topLevelDeclarations = buildInfo.topLevelDeclarations;
						if (topLevelDeclarations === undefined) {
							topLevelDeclarations = buildInfo.topLevelDeclarations = new Set();
						}
						for (const name of parser.scope.definitions.asSet()) {
							if (parser.isVariableDefined(name)) {
								topLevelDeclarations.add(name);
							}
						}
					});
				};

				normalModuleFactory.hooks.parser
					.for(JAVASCRIPT_MODULE_TYPE_AUTO)
					.tap(PLUGIN_NAME, handler);
				normalModuleFactory.hooks.parser
					.for(JAVASCRIPT_MODULE_TYPE_DYNAMIC)
					.tap(PLUGIN_NAME, handler);
				normalModuleFactory.hooks.parser
					.for(JAVASCRIPT_MODULE_TYPE_ESM)
					.tap(PLUGIN_NAME, handler);
			}
		);
	}
}

module.exports = JavascriptMetaInfoPlugin;