/*
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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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class AggressiveMergingPlugin {
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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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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(
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"AggressiveMergingPlugin",
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compilation => {
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compilation.hooks.optimizeChunksAdvanced.tap(
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"AggressiveMergingPlugin",
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chunks => {
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let combinations = [];
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chunks.forEach((a, idx) => {
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if (a.canBeInitial()) return;
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for (let i = 0; i < idx; i++) {
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const b = chunks[i];
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if (b.canBeInitial()) continue;
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combinations.push({
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a,
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b,
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improvement: undefined
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});
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}
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});
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for (const pair of combinations) {
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const a = pair.b.size({
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chunkOverhead: 0
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});
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const b = pair.a.size({
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chunkOverhead: 0
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});
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const ab = pair.b.integratedSize(pair.a, {
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chunkOverhead: 0
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});
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let newSize;
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if (ab === false) {
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pair.improvement = false;
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return;
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} else {
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newSize = ab;
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}
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pair.improvement = (a + b) / newSize;
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}
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combinations = combinations.filter(pair => {
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return pair.improvement !== false;
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});
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combinations.sort((a, b) => {
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return b.improvement - a.improvement;
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});
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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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if (pair.b.integrate(pair.a, "aggressive-merge")) {
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chunks.splice(chunks.indexOf(pair.a), 1);
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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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}
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}
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module.exports = AggressiveMergingPlugin;
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