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- /*
- MIT License http://www.opensource.org/licenses/mit-license.php
- Author Tobias Koppers @sokra
- */
- "use strict";
-
- class AggressiveMergingPlugin {
- constructor(options) {
- if (
- (options !== undefined && typeof options !== "object") ||
- Array.isArray(options)
- ) {
- throw new Error(
- "Argument should be an options object. To use defaults, pass in nothing.\nFor more info on options, see https://webpack.js.org/plugins/"
- );
- }
- this.options = options || {};
- }
-
- apply(compiler) {
- const options = this.options;
- const minSizeReduce = options.minSizeReduce || 1.5;
-
- compiler.hooks.thisCompilation.tap(
- "AggressiveMergingPlugin",
- compilation => {
- compilation.hooks.optimizeChunksAdvanced.tap(
- "AggressiveMergingPlugin",
- chunks => {
- let combinations = [];
- chunks.forEach((a, idx) => {
- if (a.canBeInitial()) return;
- for (let i = 0; i < idx; i++) {
- const b = chunks[i];
- if (b.canBeInitial()) continue;
- combinations.push({
- a,
- b,
- improvement: undefined
- });
- }
- });
-
- for (const pair of combinations) {
- const a = pair.b.size({
- chunkOverhead: 0
- });
- const b = pair.a.size({
- chunkOverhead: 0
- });
- const ab = pair.b.integratedSize(pair.a, {
- chunkOverhead: 0
- });
- let newSize;
- if (ab === false) {
- pair.improvement = false;
- return;
- } else {
- newSize = ab;
- }
-
- pair.improvement = (a + b) / newSize;
- }
- combinations = combinations.filter(pair => {
- return pair.improvement !== false;
- });
- combinations.sort((a, b) => {
- return b.improvement - a.improvement;
- });
-
- const pair = combinations[0];
-
- if (!pair) return;
- if (pair.improvement < minSizeReduce) return;
-
- if (pair.b.integrate(pair.a, "aggressive-merge")) {
- chunks.splice(chunks.indexOf(pair.a), 1);
- return true;
- }
- }
- );
- }
- );
- }
- }
-
- module.exports = AggressiveMergingPlugin;
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