Method apply

lib/optimize/AggressiveMergingPlugin.js:44–97

* Applies the plugin by registering its hooks on the compiler. * @param {Compiler} compiler the compiler instance * @returns {void}

(compiler)

	 * @returns {void}
	 */
	apply(compiler) {
		const options = this.options;
		const minSizeReduce = options.minSizeReduce || 1.5;

		compiler.hooks.thisCompilation.tap(PLUGIN_NAME, (compilation) => {
			compilation.hooks.optimizeChunks.tap(
				{
					name: PLUGIN_NAME,
					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;