Merge pull request #8452 from webpack/feature/resolveWithOptions

add getResolve method to loader context

lib/NormalModule.js

@@ -184,6 +184,21 @@ class NormalModule extends Module {
 			resolve(context, request, callback) {
 				resolver.resolve({}, context, request, {}, callback);
 			},
+			getResolve(options) {
+				const child = options ? resolver.withOptions(options) : resolver;
+				return (context, request, callback) => {
+					if (callback) {
+						child.resolve({}, context, request, {}, callback);
+					} else {
+						return new Promise((resolve, reject) => {
+							child.resolve({}, context, request, {}, (err, result) => {
+								if (err) reject(err);
+								else resolve(result);
+							});
+						});
+					}
+				};
+			},
 			emitFile: (name, content, sourceMap) => {
 				if (!this.buildInfo.assets) {
 					this.buildInfo.assets = Object.create(null);

lib/ResolverFactory.js

@@ -7,6 +7,8 @@
 const { Tapable, HookMap, SyncHook, SyncWaterfallHook } = require("tapable");
 const Factory = require("enhanced-resolve").ResolverFactory;
 
+/** @typedef {import("enhanced-resolve").Resolver} Resolver */
+
 module.exports = class ResolverFactory extends Tapable {
 	constructor() {
 		super();
@@ -53,11 +55,22 @@ module.exports = class ResolverFactory extends Tapable {
 	}
 
 	_create(type, resolveOptions) {
+		const originalResolveOptions = Object.assign({}, resolveOptions);
 		resolveOptions = this.hooks.resolveOptions.for(type).call(resolveOptions);
 		const resolver = Factory.createResolver(resolveOptions);
 		if (!resolver) {
 			throw new Error("No resolver created");
 		}
+		/** @type {Map<Object, Resolver>} */
+		const childCache = new Map();
+		resolver.withOptions = options => {
+			const cacheEntry = childCache.get(options);
+			if (cacheEntry !== undefined) return cacheEntry;
+			const mergedOptions = Object.assign({}, originalResolveOptions, options);
+			const resolver = this.get(type, mergedOptions);
+			childCache.set(options, resolver);
+			return resolver;
+		};
 		this.hooks.resolver.for(type).call(resolver, resolveOptions);
 		return resolver;
 	}

test/cases/loaders/resolve/index.js

@@ -0,0 +1,7 @@
+it("should be possible to create resolver with different options", () => {
+	const result = require("./loader!");
+	expect(result).toEqual({
+		one: "index.js",
+		two: "index.xyz"
+	});
+})

test/cases/loaders/resolve/loader.js

@@ -0,0 +1,16 @@
+const path = require("path");
+module.exports = function() {
+	const resolve1 = this.getResolve();
+	const resolve2 = this.getResolve({
+		extensions: [".xyz", ".js"]
+	});
+	return Promise.all([
+		resolve1(__dirname, "./index"),
+		resolve2(__dirname, "./index")
+	]).then(([one, two]) => {
+		return `module.exports = ${JSON.stringify({
+			one: path.basename(one),
+			two: path.basename(two),
+		})}`;
+	});
+};