webpack/lib/dependencies/RequireContextPlugin.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 { cachedSetProperty } = require("../util/cleverMerge");
const ContextElementDependency = require("./ContextElementDependency");
const RequireContextDependency = require("./RequireContextDependency");
const RequireContextDependencyParserPlugin = require("./RequireContextDependencyParserPlugin");

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

/** @type {ResolveOptions} */
const EMPTY_RESOLVE_OPTIONS = {};

class RequireContextPlugin {
	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	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
				);

				const handler = (parser, parserOptions) => {
					if (
						parserOptions.requireContext !== undefined &&
						!parserOptions.requireContext
					)
						return;

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

				normalModuleFactory.hooks.parser
					.for("javascript/auto")
					.tap("RequireContextPlugin", handler);
				normalModuleFactory.hooks.parser
					.for("javascript/dynamic")
					.tap("RequireContextPlugin", handler);

				contextModuleFactory.hooks.alternativeRequests.tap(
					"RequireContextPlugin",
					(items, options) => {
						if (items.length === 0) return items;

						const finalResolveOptions = compiler.resolverFactory.get(
							"normal",
							cachedSetProperty(
								options.resolveOptions || EMPTY_RESOLVE_OPTIONS,
								"dependencyType",
								options.category
							)
						).options;

						let newItems;
						if (!finalResolveOptions.fullySpecified) {
							newItems = [];
							for (const item of items) {
								const { request, context } = item;
								for (const ext of finalResolveOptions.extensions) {
									if (request.endsWith(ext)) {
										newItems.push({
											context,
											request: request.slice(0, -ext.length)
										});
									}
								}
								if (!finalResolveOptions.enforceExtension) {
									newItems.push(item);
								}
							}
							items = newItems;

							newItems = [];
							for (const obj of items) {
								const { request, context } = obj;
								for (const mainFile of finalResolveOptions.mainFiles) {
									if (request.endsWith(`/${mainFile}`)) {
										newItems.push({
											context,
											request: request.slice(0, -mainFile.length)
										});
										newItems.push({
											context,
											request: request.slice(0, -mainFile.length - 1)
										});
									}
								}
								newItems.push(obj);
							}
							items = newItems;
						}

						newItems = [];
						for (const item of items) {
							let hideOriginal = false;
							for (const modulesItems of finalResolveOptions.modules) {
								if (Array.isArray(modulesItems)) {
									for (const dir of modulesItems) {
										if (item.request.startsWith(`./${dir}/`)) {
											newItems.push({
												context: item.context,
												request: item.request.slice(dir.length + 3)
											});
											hideOriginal = true;
										}
									}
								} else {
									const dir = modulesItems.replace(/\\/g, "/");
									const fullPath =
										item.context.replace(/\\/g, "/") + item.request.slice(1);
									if (fullPath.startsWith(dir)) {
										newItems.push({
											context: item.context,
											request: fullPath.slice(dir.length + 1)
										});
									}
								}
							}
							if (!hideOriginal) {
								newItems.push(item);
							}
						}
						return newItems;
					}
				);
			}
		);
	}
}
module.exports = RequireContextPlugin;