Method apply

lib/CleanPlugin.js:352–484

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

(compiler)

	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.validate.tap(PLUGIN_NAME, () => {
			compiler.validate(
				() => {
					const { definitions } = require("../schemas/WebpackOptions.json");

					return {
						definitions,
						oneOf: [{ $ref: "#/definitions/CleanOptions" }]
					};
				},
				this.options,
				{
					name: "Clean Plugin",
					baseDataPath: "options"
				}
			);
		});

		const { keep } = this.options;

		/** @type {boolean} */
		const dry = this.options.dry || false;
		/** @type {KeepFn} */
		const keepFn =
			typeof keep === "function"
				? keep
				: typeof keep === "string"
					? (path) => path.startsWith(keep)
					: typeof keep === "object" && keep.test
						? (path) => keep.test(path)
						: () => false;

		// We assume that no external modification happens while the compiler is active
		// So we can store the old assets and only diff to them to avoid fs access on
		// incremental builds
		/** @type {undefined | Assets} */
		let oldAssets;

		compiler.hooks.emit.tapAsync(
			{
				name: PLUGIN_NAME,
				stage: 100
			},
			(compilation, callback) => {
				const hooks = CleanPlugin.getCompilationHooks(compilation);
				const logger = compilation.getLogger(`webpack.${PLUGIN_NAME}`);
				const fs = /** @type {OutputFileSystem} */ (compiler.outputFileSystem);

				if (!fs.readdir) {
					return callback(
						new Error(
							`${PLUGIN_NAME}: Output filesystem doesn't support listing directories (readdir)`
						)
					);
				}

				/** @type {Assets} */