webpack/lib/optimize/RemoveEmptyChunksPlugin.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 Tobias Koppers @sokra
*/

"use strict";

const { STAGE_ADVANCED, STAGE_BASIC } = require("../OptimizationStages");

/** @typedef {import("../Chunk")} Chunk */
/** @typedef {import("../Compiler")} Compiler */

const PLUGIN_NAME = "RemoveEmptyChunksPlugin";

class RemoveEmptyChunksPlugin {
	/**
	 * 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) => {
			/**
			 * Handles the hook callback for this code path.
			 * @param {Iterable<Chunk>} chunks the chunks array
			 * @returns {void}
			 */
			const handler = (chunks) => {
				const chunkGraph = compilation.chunkGraph;
				for (const chunk of chunks) {
					if (
						chunkGraph.getNumberOfChunkModules(chunk) === 0 &&
						!chunk.hasRuntime() &&
						chunkGraph.getNumberOfEntryModules(chunk) === 0
					) {
						compilation.chunkGraph.disconnectChunk(chunk);
						compilation.chunks.delete(chunk);
					}
				}
			};

			compilation.hooks.optimizeChunks.tap(
				{
					name: PLUGIN_NAME,
					stage: STAGE_BASIC
				},
				handler
			);
			compilation.hooks.optimizeChunks.tap(
				{
					name: PLUGIN_NAME,
					stage: STAGE_ADVANCED
				},
				handler
			);
		});
	}
}

module.exports = RemoveEmptyChunksPlugin;