webpack/lib/performance/DuplicatePackagesWarning.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 Alexander Akait @alexander-akait
*/

"use strict";

const WebpackError = require("../errors/WebpackError");

/** @import Module from "../Module" */
/** @import ModuleGraph from "../ModuleGraph" */
/** @import NormalModule from "../NormalModule" */
/** @import RequestShortener from "../RequestShortener" */
/** @import { PackageCopy } from "./DuplicatePackagesPlugin" */

/**
 * @param {Module} module the module
 * @returns {string | undefined} directory of the package the module belongs to
 */
const getPackagePath = (module) => {
	const resolveData =
		/** @type {NormalModule} */
		(module).resourceResolveData;
	return resolveData && resolveData.descriptionFileRoot;
};

/**
 * Finds a module outside of the copy that pulled it into the build, so the
 * warning can name the dependency responsible for this copy.
 * @param {PackageCopy} copy the copy
 * @param {ModuleGraph} moduleGraph the module graph
 * @returns {Module | undefined} a module importing this copy, when there is one
 */
const findImporter = (copy, moduleGraph) => {
	for (const module of copy.modules) {
		for (const origin of moduleGraph
			.getIncomingConnectionsByOriginModule(module)
			.keys()) {
			if (origin && getPackagePath(origin) !== copy.path) return origin;
		}
	}
};

/**
 * Warning emitted when one package is included more than once in a build,
 * either in different versions or as several copies of the same version.
 */
class DuplicatePackagesWarning extends WebpackError {
	/**
	 * @param {string} name name of the package
	 * @param {PackageCopy[]} copies copies of the package, sorted by path
	 * @param {ModuleGraph} moduleGraph the module graph
	 * @param {RequestShortener} requestShortener the request shortener
	 */
	constructor(name, copies, moduleGraph, requestShortener) {
		const versions = new Set(copies.map((copy) => copy.version));
		const headline =
			versions.size > 1
				? `Multiple versions of the package "${name}" (${[...versions].join(", ")}) are included in this build:`
				: `The package "${name}" (${copies[0].version}) is included ${copies.length} times in this build:`;
		const copiesList = copies
			.map((copy) => {
				const importer = findImporter(copy, moduleGraph);
				let message = `* ${copy.version} from ${requestShortener.shorten(copy.path)}, ${copy.modules.length} module(s)`;
				if (importer !== undefined) {
					message += `\n    Included by ${importer.readableIdentifier(requestShortener)}`;
				}
				return message;
			})
			.join("\n");
		super(`webpack performance recommendations:
${headline}
${copiesList}
Every copy is bundled separately and has its own module state, which increases the output size and can break \`instanceof\` checks and configuration shared through the package.
Align the version ranges requiring this package, or force a single version with "resolutions"/"overrides" in your package.json.`);

		/** @type {string} */
		this.name = "DuplicatePackagesWarning";
		/** @type {Module} */
		this.module = copies[0].modules[0];
	}
}

module.exports = DuplicatePackagesWarning;