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 ModuleFilenameHelpers = require("./ModuleFilenameHelpers");
const Template = require("./Template");

const validateOptions = require("schema-utils");
const schema = require("../schemas/plugins/BannerPlugin.json");

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

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

class BannerPlugin {
	/**
	 * @param {BannerPluginArgument} options options object
	 */
	constructor(options) {
		if (arguments.length > 1) {
			throw new Error(
				"BannerPlugin only takes one argument (pass an options object)"
			);
		}

		validateOptions(schema, options, "Banner Plugin");

		if (typeof options === "string" || typeof options === "function") {
			options = {
				banner: options
			};
		}

		/** @type {BannerPluginOptions} */
		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(compiler) {
		const options = this.options;
		const banner = this.banner;
		const matchObject = ModuleFilenameHelpers.matchObject.bind(
			undefined,
			options
		);

		compiler.hooks.compilation.tap("BannerPlugin", compilation => {
			compilation.hooks.optimizeChunkAssets.tap("BannerPlugin", chunks => {
				for (const chunk of chunks) {
					if (options.entryOnly && !chunk.canBeInitial()) {
						continue;
					}

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

						let query = "";
						let filename = file;
						const hash = compilation.hash;
						const querySplit = filename.indexOf("?");

						if (querySplit >= 0) {
							query = filename.substr(querySplit);
							filename = filename.substr(0, querySplit);
						}

						const lastSlashIndex = filename.lastIndexOf("/");

						const basename =
							lastSlashIndex === -1
								? filename
								: filename.substr(lastSlashIndex + 1);

						const data = {
							hash,
							chunk,
							filename,
							basename,
							query
						};

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

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

module.exports = BannerPlugin;