Method apply

lib/BannerPlugin.js:84–143

* Validates the configured options and injects rendered banner comments into * matching compilation assets at the configured process-assets stage. * @param {Compiler} compiler the compiler instance * @returns {void}

(compiler)

	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.validate.tap(PLUGIN_NAME, () => {
			compiler.validate(
				() => require("../schemas/plugins/BannerPlugin.json"),
				this.options,
				{
					name: "Banner Plugin",
					baseDataPath: "options"
				},
				(options) => require("../schemas/plugins/BannerPlugin.check")(options)
			);
		});
		const options = this.options;
		const banner = this.banner;
		const matchObject = ModuleFilenameHelpers.matchObject.bind(
			undefined,
			options
		);
		/** @type {WeakMap<Source, { source: ConcatSource, comment: string }>} */
		const cache = new WeakMap();
		const stage =
			this.options.stage || Compilation.PROCESS_ASSETS_STAGE_ADDITIONS;

		compiler.hooks.compilation.tap(PLUGIN_NAME, (compilation) => {
			compilation.hooks.processAssets.tap({ name: PLUGIN_NAME, stage }, () => {
				for (const chunk of compilation.chunks) {
					if (options.entryOnly && !chunk.canBeInitial()) {
						continue;
					}

					for (const file of chunk.files) {
						if (!matchObject(file)) {
							continue;
						}

						/** @type {PathDataChunk} */
						const data = { chunk, filename: file };

						const comment = compilation.getPath(
							/** @type {string | import("./TemplatedPathPlugin").TemplatePathFn<PathDataChunk>} */
							(banner),
							data
						);

						compilation.updateAsset(file, (old) => {
							const cached = cache.get(old);
							if (!cached || cached.comment !== comment) {
								const source = options.footer
									? new ConcatSource(old, "\n", comment)
									: new ConcatSource(comment, "\n", old);
								cache.set(old, { source, comment });
								return source;
							}
							return cached.source;
						});
					}
				}
			});