source: frontend/node_modules/webpack/lib/optimize/RemoveEmptyChunksPlugin.js

/*
        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;