webpack/lib/ContextReplacementPlugin.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 ContextElementDependency = require("./dependencies/ContextElementDependency");
const { join } = require("./util/fs");

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

class ContextReplacementPlugin {
	/**
	 * @param {RegExp} resourceRegExp A regular expression that determines which files will be selected
	 * @param {TODO=} newContentResource A new resource to replace the match
	 * @param {TODO=} newContentRecursive If true, all subdirectories are searched for matches
	 * @param {TODO=} newContentRegExp A regular expression that determines which files will be selected
	 */
	constructor(
		resourceRegExp,
		newContentResource,
		newContentRecursive,
		newContentRegExp
	) {
		this.resourceRegExp = resourceRegExp;

		if (typeof newContentResource === "function") {
			this.newContentCallback = newContentResource;
		} else if (
			typeof newContentResource === "string" &&
			typeof newContentRecursive === "object"
		) {
			this.newContentResource = newContentResource;
			this.newContentCreateContextMap = (fs, callback) => {
				callback(null, newContentRecursive);
			};
		} else if (
			typeof newContentResource === "string" &&
			typeof newContentRecursive === "function"
		) {
			this.newContentResource = newContentResource;
			this.newContentCreateContextMap = newContentRecursive;
		} else {
			if (typeof newContentResource !== "string") {
				newContentRegExp = newContentRecursive;
				newContentRecursive = newContentResource;
				newContentResource = undefined;
			}
			if (typeof newContentRecursive !== "boolean") {
				newContentRegExp = newContentRecursive;
				newContentRecursive = undefined;
			}
			this.newContentResource = newContentResource;
			this.newContentRecursive = newContentRecursive;
			this.newContentRegExp = newContentRegExp;
		}
	}

	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		const resourceRegExp = this.resourceRegExp;
		const newContentCallback = this.newContentCallback;
		const newContentResource = this.newContentResource;
		const newContentRecursive = this.newContentRecursive;
		const newContentRegExp = this.newContentRegExp;
		const newContentCreateContextMap = this.newContentCreateContextMap;

		compiler.hooks.contextModuleFactory.tap("ContextReplacementPlugin", cmf => {
			cmf.hooks.beforeResolve.tap("ContextReplacementPlugin", result => {
				if (!result) return;
				if (resourceRegExp.test(result.request)) {
					if (newContentResource !== undefined) {
						result.request = newContentResource;
					}
					if (newContentRecursive !== undefined) {
						result.recursive = newContentRecursive;
					}
					if (newContentRegExp !== undefined) {
						result.regExp = newContentRegExp;
					}
					if (typeof newContentCallback === "function") {
						newContentCallback(result);
					} else {
						for (const d of result.dependencies) {
							if (d.critical) d.critical = false;
						}
					}
				}
				return result;
			});
			cmf.hooks.afterResolve.tap("ContextReplacementPlugin", result => {
				if (!result) return;
				if (resourceRegExp.test(result.resource)) {
					if (newContentResource !== undefined) {
						if (
							newContentResource.startsWith("/") ||
							(newContentResource.length > 1 && newContentResource[1] === ":")
						) {
							result.resource = newContentResource;
						} else {
							result.resource = join(
								/** @type {InputFileSystem} */ (compiler.inputFileSystem),
								result.resource,
								newContentResource
							);
						}
					}
					if (newContentRecursive !== undefined) {
						result.recursive = newContentRecursive;
					}
					if (newContentRegExp !== undefined) {
						result.regExp = newContentRegExp;
					}
					if (typeof newContentCreateContextMap === "function") {
						result.resolveDependencies =
							createResolveDependenciesFromContextMap(
								newContentCreateContextMap
							);
					}
					if (typeof newContentCallback === "function") {
						const origResource = result.resource;
						newContentCallback(result);
						if (
							result.resource !== origResource &&
							!result.resource.startsWith("/") &&
							(result.resource.length <= 1 || result.resource[1] !== ":")
						) {
							// When the function changed it to an relative path
							result.resource = join(
								/** @type {InputFileSystem} */ (compiler.inputFileSystem),
								origResource,
								result.resource
							);
						}
					} else {
						for (const d of result.dependencies) {
							if (d.critical) d.critical = false;
						}
					}
				}
				return result;
			});
		});
	}
}

const createResolveDependenciesFromContextMap = createContextMap => {
	const resolveDependenciesFromContextMap = (fs, options, callback) => {
		createContextMap(fs, (err, map) => {
			if (err) return callback(err);
			const dependencies = Object.keys(map).map(key => {
				return new ContextElementDependency(
					map[key] + options.resourceQuery + options.resourceFragment,
					key,
					options.category,
					options.referencedExports
				);
			});
			callback(null, dependencies);
		});
	};
	return resolveDependenciesFromContextMap;
};

module.exports = ContextReplacementPlugin;