webpack/lib/ids/SyncModuleIdsPlugin.js

Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports 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 { WebpackError } = require("..");
const { getUsedModuleIdsAndModules } = require("./IdHelpers");

/** @typedef {import("../Compiler")} Compiler */
/** @typedef {import("../Module")} Module */
/** @typedef {import("../util/fs").IntermediateFileSystem} IntermediateFileSystem */

const plugin = "SyncModuleIdsPlugin";

/**
 * @typedef {object} SyncModuleIdsPluginOptions
 * @property {string} path path to file
 * @property {string=} context context for module names
 * @property {((module: Module) => boolean)=} test selector for modules
 * @property {"read" | "create" | "merge" | "update"=} mode operation mode (defaults to merge)
 */

class SyncModuleIdsPlugin {
	/**
	 * @param {SyncModuleIdsPluginOptions} options options
	 */
	constructor({ path, context, test, mode }) {
		this._path = path;
		this._context = context;
		this._test = test || (() => true);
		const readAndWrite = !mode || mode === "merge" || mode === "update";
		this._read = readAndWrite || mode === "read";
		this._write = readAndWrite || mode === "create";
		this._prune = mode === "update";
	}

	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		/** @type {Map<string, string | number>} */
		let data;
		let dataChanged = false;
		if (this._read) {
			compiler.hooks.readRecords.tapAsync(plugin, callback => {
				const fs =
					/** @type {IntermediateFileSystem} */
					(compiler.intermediateFileSystem);
				fs.readFile(this._path, (err, buffer) => {
					if (err) {
						if (err.code !== "ENOENT") {
							return callback(err);
						}
						return callback();
					}
					const json = JSON.parse(/** @type {Buffer} */ (buffer).toString());
					data = new Map();
					for (const key of Object.keys(json)) {
						data.set(key, json[key]);
					}
					dataChanged = false;
					return callback();
				});
			});
		}
		if (this._write) {
			compiler.hooks.emitRecords.tapAsync(plugin, callback => {
				if (!data || !dataChanged) return callback();
				/** @type {{[key: string]: string | number}} */
				const json = {};
				const sorted = Array.from(data).sort(([a], [b]) => (a < b ? -1 : 1));
				for (const [key, value] of sorted) {
					json[key] = value;
				}
				const fs =
					/** @type {IntermediateFileSystem} */
					(compiler.intermediateFileSystem);
				fs.writeFile(this._path, JSON.stringify(json), callback);
			});
		}
		compiler.hooks.thisCompilation.tap(plugin, compilation => {
			const associatedObjectForCache = compiler.root;
			const context = this._context || compiler.context;
			if (this._read) {
				compilation.hooks.reviveModules.tap(plugin, (_1, _2) => {
					if (!data) return;
					const { chunkGraph } = compilation;
					const [usedIds, modules] = getUsedModuleIdsAndModules(
						compilation,
						this._test
					);
					for (const module of modules) {
						const name = module.libIdent({
							context,
							associatedObjectForCache
						});
						if (!name) continue;
						const id = data.get(name);
						const idAsString = `${id}`;
						if (usedIds.has(idAsString)) {
							const err = new WebpackError(
								`SyncModuleIdsPlugin: Unable to restore id '${id}' from '${this._path}' as it's already used.`
							);
							err.module = module;
							compilation.errors.push(err);
						}
						chunkGraph.setModuleId(module, /** @type {string | number} */ (id));
						usedIds.add(idAsString);
					}
				});
			}
			if (this._write) {
				compilation.hooks.recordModules.tap(plugin, modules => {
					const { chunkGraph } = compilation;
					let oldData = data;
					if (!oldData) {
						oldData = data = new Map();
					} else if (this._prune) {
						data = new Map();
					}
					for (const module of modules) {
						if (this._test(module)) {
							const name = module.libIdent({
								context,
								associatedObjectForCache
							});
							if (!name) continue;
							const id = chunkGraph.getModuleId(module);
							if (id === null) continue;
							const oldId = oldData.get(name);
							if (oldId !== id) {
								dataChanged = true;
							} else if (data === oldData) {
								continue;
							}
							data.set(name, id);
						}
					}
					if (data.size !== oldData.size) dataChanged = true;
				});
			}
		});
	}
}

module.exports = SyncModuleIdsPlugin;