mirror of https://github.com/webpack/webpack.git
98 lines
2.4 KiB
JavaScript
98 lines
2.4 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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const { STAGE_ADVANCED } = require("../OptimizationStages");
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/** @typedef {import("../Chunk")} Chunk */
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/** @typedef {import("../Compiler")} Compiler */
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/**
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* @typedef {object} AggressiveMergingPluginOptions
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* @property {number=} minSizeReduce minimal size reduction to trigger merging
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*/
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const PLUGIN_NAME = "AggressiveMergingPlugin";
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class AggressiveMergingPlugin {
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/**
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* @param {AggressiveMergingPluginOptions=} options options object
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*/
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constructor(options) {
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if (
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(options !== undefined && typeof options !== "object") ||
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Array.isArray(options)
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) {
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throw new Error(
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"Argument should be an options object. To use defaults, pass in nothing.\nFor more info on options, see https://webpack.js.org/plugins/"
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);
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}
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this.options = options || {};
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}
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/**
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* Apply the plugin
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* @param {Compiler} compiler the compiler instance
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* @returns {void}
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*/
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apply(compiler) {
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const options = this.options;
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const minSizeReduce = options.minSizeReduce || 1.5;
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compiler.hooks.thisCompilation.tap(PLUGIN_NAME, compilation => {
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compilation.hooks.optimizeChunks.tap(
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{
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name: PLUGIN_NAME,
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stage: STAGE_ADVANCED
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},
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chunks => {
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const chunkGraph = compilation.chunkGraph;
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/** @type {{a: Chunk, b: Chunk, improvement: number}[]} */
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const combinations = [];
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for (const a of chunks) {
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if (a.canBeInitial()) continue;
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for (const b of chunks) {
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if (b.canBeInitial()) continue;
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if (b === a) break;
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if (!chunkGraph.canChunksBeIntegrated(a, b)) {
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continue;
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}
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const aSize = chunkGraph.getChunkSize(b, {
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chunkOverhead: 0
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});
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const bSize = chunkGraph.getChunkSize(a, {
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chunkOverhead: 0
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});
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const abSize = chunkGraph.getIntegratedChunksSize(b, a, {
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chunkOverhead: 0
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});
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const improvement = (aSize + bSize) / abSize;
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combinations.push({
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a,
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b,
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improvement
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});
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}
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}
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combinations.sort((a, b) => b.improvement - a.improvement);
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const pair = combinations[0];
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if (!pair) return;
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if (pair.improvement < minSizeReduce) return;
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chunkGraph.integrateChunks(pair.b, pair.a);
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compilation.chunks.delete(pair.a);
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return true;
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}
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);
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});
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}
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}
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module.exports = AggressiveMergingPlugin;
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