webpack/lib/LibManifestPlugin.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 asyncLib = require("neo-async");
const EntryDependency = require("./dependencies/EntryDependency");
const { compareModulesById } = require("./util/comparators");
const { dirname, mkdirp } = require("./util/fs");

/** @typedef {import("./Compiler")} Compiler */

/**
 * @typedef {Object} ManifestModuleData
 * @property {string | number} id
 * @property {Object} buildMeta
 * @property {boolean | string[]} exports
 */

/**
 * @template T
 * @param {Iterable<T>} iterable iterable
 * @param {function(T): boolean} filter predicate
 * @returns {boolean} true, if some items match the filter predicate
 */
const someInIterable = (iterable, filter) => {
	for (const item of iterable) {
		if (filter(item)) return true;
	}
	return false;
};

class LibManifestPlugin {
	constructor(options) {
		this.options = options;
	}

	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.emit.tapAsync(
			"LibManifestPlugin",
			(compilation, callback) => {
				const moduleGraph = compilation.moduleGraph;
				asyncLib.forEach(
					Array.from(compilation.chunks),
					(chunk, callback) => {
						if (!chunk.canBeInitial()) {
							callback();
							return;
						}
						const chunkGraph = compilation.chunkGraph;
						const targetPath = compilation.getPath(this.options.path, {
							chunk
						});
						const name =
							this.options.name &&
							compilation.getPath(this.options.name, {
								chunk
							});
						const content = Object.create(null);
						for (const module of chunkGraph.getOrderedChunkModulesIterable(
							chunk,
							compareModulesById(chunkGraph)
						)) {
							if (
								this.options.entryOnly &&
								!someInIterable(
									moduleGraph.getIncomingConnections(module),
									c => c.dependency instanceof EntryDependency
								)
							) {
								continue;
							}
							const ident = module.libIdent({
								context: this.options.context || compiler.options.context,
								associatedObjectForCache: compiler.root
							});
							if (ident) {
								const exportsInfo = moduleGraph.getExportsInfo(module);
								const providedExports = exportsInfo.getProvidedExports();
								/** @type {ManifestModuleData} */
								const data = {
									id: chunkGraph.getModuleId(module),
									buildMeta: module.buildMeta,
									exports: Array.isArray(providedExports)
										? providedExports
										: undefined
								};
								content[ident] = data;
							}
						}
						const manifest = {
							name,
							type: this.options.type,
							content
						};
						// Apply formatting to content if format flag is true;
						const manifestContent = this.options.format
							? JSON.stringify(manifest, null, 2)
							: JSON.stringify(manifest);
						const buffer = Buffer.from(manifestContent, "utf8");
						mkdirp(
							compiler.intermediateFileSystem,
							dirname(compiler.intermediateFileSystem, targetPath),
							err => {
								if (err) return callback(err);
								compiler.intermediateFileSystem.writeFile(
									targetPath,
									buffer,
									callback
								);
							}
						);
					},
					callback
				);
			}
		);
	}
}
module.exports = LibManifestPlugin;