webpack/lib/dependencies/RequireContextPlugin.js

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

const RequireContextDependency = require("./RequireContextDependency");
const ContextElementDependency = require("./ContextElementDependency");

const RequireContextDependencyParserPlugin = require("./RequireContextDependencyParserPlugin");

class RequireContextPlugin {
	constructor(modulesDirectories, extensions, mainFiles) {
		if(!Array.isArray(modulesDirectories))
			throw new Error("modulesDirectories must be an array");
		if(!Array.isArray(extensions))
			throw new Error("extensions must be an array");
		this.modulesDirectories = modulesDirectories;
		this.extensions = extensions;
		this.mainFiles = mainFiles;
	}

	apply(compiler) {
		compiler.hooks.compilation.tap("RequireContextPlugin", (compilation, {
			contextModuleFactory,
			normalModuleFactory
		}) => {
			compilation.dependencyFactories.set(RequireContextDependency, contextModuleFactory);
			compilation.dependencyTemplates.set(RequireContextDependency, new RequireContextDependency.Template());

			compilation.dependencyFactories.set(ContextElementDependency, normalModuleFactory);

			normalModuleFactory.plugin(["parser javascript/auto", "parser javascript/dynamic"], (parser, parserOptions) => {

				if(typeof parserOptions.requireContext !== "undefined" && !parserOptions.requireContext)
					return;

				parser.apply(new RequireContextDependencyParserPlugin());
			});

			contextModuleFactory.hooks.alternatives.tapAsync("RequireContextPlugin", (items, callback) => {
				if(items.length === 0) return callback(null, items);

				callback(null, items.map((obj) => {
					return this.extensions.filter((ext) => {
						const l = obj.request.length;
						return l > ext.length && obj.request.substr(l - ext.length, l) === ext;
					}).map((ext) => {
						const l = obj.request.length;
						return {
							context: obj.context,
							request: obj.request.substr(0, l - ext.length)
						};
					}).concat(obj);
				}).reduce((a, b) => a.concat(b), []));
			});

			contextModuleFactory.hooks.alternatives.tapAsync("RequireContextPlugin", (items, callback) => {
				if(items.length === 0) return callback(null, items);

				callback(null, items.map((obj) => {
					return this.mainFiles.filter((mainFile) => {
						const l = obj.request.length;
						return l > mainFile.length + 1 && obj.request.substr(l - mainFile.length - 1, l) === "/" + mainFile;
					}).map((mainFile) => {
						const l = obj.request.length;
						return [{
							context: obj.context,
							request: obj.request.substr(0, l - mainFile.length)
						}, {
							context: obj.context,
							request: obj.request.substr(0, l - mainFile.length - 1)
						}];
					}).reduce((a, b) => a.concat(b), []).concat(obj);
				}).reduce((a, b) => a.concat(b), []));
			});

			contextModuleFactory.hooks.alternatives.tapAsync("RequireContextPlugin", (items, callback) => {
				if(items.length === 0) return callback(null, items);

				callback(null, items.map((obj) => {
					for(let i = 0; i < this.modulesDirectories.length; i++) {
						const dir = this.modulesDirectories[i];
						const idx = obj.request.indexOf("./" + dir + "/");
						if(idx === 0) {
							obj.request = obj.request.slice(dir.length + 3);
							break;
						}
					}
					return obj;
				}));
			});
		});
	}
}
module.exports = RequireContextPlugin;