webpack/lib/BannerPlugin.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const { ConcatSource } = require("webpack-sources");
const Compilation = require("./Compilation");
const ModuleFilenameHelpers = require("./ModuleFilenameHelpers");
const Template = require("./Template");
const createSchemaValidation = require("./util/create-schema-validation");

/** @typedef {import("../declarations/plugins/BannerPlugin").BannerPluginArgument} BannerPluginArgument */
/** @typedef {import("../declarations/plugins/BannerPlugin").BannerPluginOptions} BannerPluginOptions */
/** @typedef {import("./Compiler")} Compiler */

const validate = createSchemaValidation(
	require("../schemas/plugins/BannerPlugin.check.js"),
	() => require("../schemas/plugins/BannerPlugin.json"),
	{
		name: "Banner Plugin",
		baseDataPath: "options"
	}
);

const wrapComment = str => {
	if (!str.includes("\n")) {
		return Template.toComment(str);
	}
	return `/*!\n * ${str
		.replace(/\*\//g, "* /")
		.split("\n")
		.join("\n * ")
		.replace(/\s+\n/g, "\n")
		.trimRight()}\n */`;
};

class BannerPlugin {
	/**
	 * @param {BannerPluginArgument} options options object
	 */
	constructor(options) {
		if (typeof options === "string" || typeof options === "function") {
			options = {
				banner: options
			};
		}

		validate(options);

		this.options = options;

		const bannerOption = options.banner;
		if (typeof bannerOption === "function") {
			const getBanner = bannerOption;
			this.banner = this.options.raw
				? getBanner
				: data => wrapComment(getBanner(data));
		} else {
			const banner = this.options.raw
				? bannerOption
				: wrapComment(bannerOption);
			this.banner = () => banner;
		}
	}

	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		const options = this.options;
		const banner = this.banner;
		const matchObject = ModuleFilenameHelpers.matchObject.bind(
			undefined,
			options
		);

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

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

							const data = {
								chunk,
								filename: file
							};

							const comment = compilation.getPath(banner, data);

							compilation.updateAsset(
								file,
								old => new ConcatSource(comment, "\n", old)
							);
						}
					}
				}
			);
		});
	}
}

module.exports = BannerPlugin;