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app_vue/node_modules/webpack/lib/optimize/AggressiveMergingPlugin.js

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+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const { STAGE_ADVANCED } = require("../OptimizationStages");
+
+/** @typedef {import("../Chunk")} Chunk */
+/** @typedef {import("../Compiler")} Compiler */
+
+/**
+ * @typedef {object} AggressiveMergingPluginOptions
+ * @property {number=} minSizeReduce minimal size reduction to trigger merging
+ */
+
+class AggressiveMergingPlugin {
+	/**
+	 * @param {AggressiveMergingPluginOptions=} options options object
+	 */
+	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 the plugin
+	 * @param {Compiler} compiler the compiler instance
+	 * @returns {void}
+	 */
+	apply(compiler) {
+		const options = this.options;
+		const minSizeReduce = options.minSizeReduce || 1.5;
+
+		compiler.hooks.thisCompilation.tap(
+			"AggressiveMergingPlugin",
+			compilation => {
+				compilation.hooks.optimizeChunks.tap(
+					{
+						name: "AggressiveMergingPlugin",
+						stage: STAGE_ADVANCED
+					},
+					chunks => {
+						const chunkGraph = compilation.chunkGraph;
+						/** @type {{a: Chunk, b: Chunk, improvement: number}[]} */
+						const combinations = [];
+						for (const a of chunks) {
+							if (a.canBeInitial()) continue;
+							for (const b of chunks) {
+								if (b.canBeInitial()) continue;
+								if (b === a) break;
+								if (!chunkGraph.canChunksBeIntegrated(a, b)) {
+									continue;
+								}
+								const aSize = chunkGraph.getChunkSize(b, {
+									chunkOverhead: 0
+								});
+								const bSize = chunkGraph.getChunkSize(a, {
+									chunkOverhead: 0
+								});
+								const abSize = chunkGraph.getIntegratedChunksSize(b, a, {
+									chunkOverhead: 0
+								});
+								const improvement = (aSize + bSize) / abSize;
+								combinations.push({
+									a,
+									b,
+									improvement
+								});
+							}
+						}
+
+						combinations.sort((a, b) => b.improvement - a.improvement);
+
+						const pair = combinations[0];
+
+						if (!pair) return;
+						if (pair.improvement < minSizeReduce) return;
+
+						chunkGraph.integrateChunks(pair.b, pair.a);
+						compilation.chunks.delete(pair.a);
+						return true;
+					}
+				);
+			}
+		);
+	}
+}
+
+module.exports = AggressiveMergingPlugin;