webpack/lib/performance/ConflictingResourceHintsPlugin.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 ConflictingResourceHintsWarning = require("../errors/ConflictingResourceHintsWarning");
const { compareStrings } = require("../util/comparators");

/** @import { PerformanceOptions } from "../../declarations/WebpackOptions" */
/** @import ChunkGroup from "../ChunkGroup" */
/** @import Compiler from "../Compiler" */
/**
 * @import {
 * 	ConflictingResourceHintDetails
 * } from "../errors/ConflictingResourceHintsWarning"
 */

const PLUGIN_NAME = "ConflictingResourceHintsPlugin";

/**
 * Names a chunk group for a message, falling back to its chunks: an `import()`
 * without `webpackChunkName` produces a group with no name of its own.
 * @param {ChunkGroup} chunkGroup a chunk group
 * @returns {string} a name for it
 */
const getChunkGroupName = (chunkGroup) =>
	chunkGroup.name ||
	chunkGroup.chunks.map((chunk) => chunk.name || `${chunk.id}`).join(", ");

class ConflictingResourceHintsPlugin {
	/**
	 * Creates an instance of ConflictingResourceHintsPlugin.
	 * @param {PerformanceOptions} options the plugin options
	 */
	constructor(options) {
		/** @type {PerformanceOptions["hints"]} */
		this.hints = options.hints;
	}

	/**
	 * Applies the plugin by registering its hooks on the compiler.
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		const hints = this.hints;

		compiler.hooks.compilation.tap(PLUGIN_NAME, (compilation) => {
			compilation.hooks.afterSeal.tap(PLUGIN_NAME, () => {
				const { chunkGraph, moduleGraph } = compilation;
				/** @type {ConflictingResourceHintDetails[]} */
				const links = [];

				for (const chunkGroup of compilation.chunkGroups) {
					const children = chunkGroup.getChildrenByOrders(
						moduleGraph,
						chunkGraph
					);

					if (!children.prefetch || !children.preload) continue;

					const preloaded = new Set(children.preload);

					for (const child of children.prefetch) {
						if (!preloaded.has(child)) continue;

						links.push({
							parent: getChunkGroupName(chunkGroup),
							child: getChunkGroupName(child)
						});
					}
				}

				if (links.length === 0) return;

				// Chunk group iteration order is not stable across runs.
				links.sort(
					(a, b) =>
						compareStrings(a.parent, b.parent) ||
						compareStrings(a.child, b.child)
				);

				const warning = new ConflictingResourceHintsWarning(links);

				if (hints === "error") {
					compilation.errors.push(warning);
				} else if (hints === "stats") {
					compilation.hints.push(warning);
				} else {
					compilation.warnings.push(warning);
				}
			});
		});
	}
}

module.exports = ConflictingResourceHintsPlugin;