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4 years ago
/*
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;