webpack/lib/optimize/OccurrenceChunkOrderPlugin.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support 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 Tobias Koppers @sokra
*/
"use strict";

const validateOptions = require("schema-utils");
const schema = require("../../schemas/plugins/optimize/OccurrenceOrderChunkIdsPlugin.json");

/** @typedef {import("../../declarations/plugins/optimize/OccurrenceOrderChunkIdsPlugin").OccurrenceOrderChunkIdsPluginOptions} OccurrenceOrderChunkIdsPluginOptions */

class OccurrenceOrderChunkIdsPlugin {
	/**
	 * @param {OccurrenceOrderChunkIdsPluginOptions=} options options object
	 */
	constructor(options = {}) {
		validateOptions(schema, options, "Occurrence Order Chunk Ids Plugin");
		this.options = options;
	}

	apply(compiler) {
		const prioritiseInitial = this.options.prioritiseInitial;
		compiler.hooks.compilation.tap(
			"OccurrenceOrderChunkIdsPlugin",
			compilation => {
				compilation.hooks.optimizeChunkOrder.tap(
					"OccurrenceOrderChunkIdsPlugin",
					chunks => {
						const occursInInitialChunksMap = new Map();
						const originalOrder = new Map();

						let i = 0;
						for (const c of chunks) {
							let occurs = 0;
							for (const chunkGroup of c.groupsIterable) {
								for (const parent of chunkGroup.parentsIterable) {
									if (parent.isInitial()) occurs++;
								}
							}
							occursInInitialChunksMap.set(c, occurs);
							originalOrder.set(c, i++);
						}

						chunks.sort((a, b) => {
							if (prioritiseInitial) {
								const aEntryOccurs = occursInInitialChunksMap.get(a);
								const bEntryOccurs = occursInInitialChunksMap.get(b);
								if (aEntryOccurs > bEntryOccurs) return -1;
								if (aEntryOccurs < bEntryOccurs) return 1;
							}
							const aOccurs = a.getNumberOfGroups();
							const bOccurs = b.getNumberOfGroups();
							if (aOccurs > bOccurs) return -1;
							if (aOccurs < bOccurs) return 1;
							const orgA = originalOrder.get(a);
							const orgB = originalOrder.get(b);
							return orgA - orgB;
						});
					}
				);
			}
		);
	}
}

module.exports = OccurrenceOrderChunkIdsPlugin;