feat: implement the defaultAsyncResolver

Author: JounQin

e2e/__tests__/__snapshots__/moduleNameMapper.test.ts.snap

@@ -41,7 +41,7 @@ exports[`moduleNameMapper wrong array configuration 1`] = `
       12 | module.exports = () => 'test';
       13 |
 
-      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:1122:17)
+      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:1129:17)
       at Object.require (index.js:10:1)
       at Object.require (__tests__/index.js:10:20)"
 `;
@@ -71,7 +71,7 @@ exports[`moduleNameMapper wrong configuration 1`] = `
       12 | module.exports = () => 'test';
       13 |
 
-      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:1122:17)
+      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:1129:17)
       at Object.require (index.js:10:1)
       at Object.require (__tests__/index.js:10:20)"
 `;

e2e/__tests__/__snapshots__/requireMissingExt.test.ts.snap

@@ -26,7 +26,7 @@ exports[`shows a proper error from deep requires 1`] = `
       12 | test('dummy', () => {
       13 |   expect(1).toBe(1);
 
-      at Resolver._throwModNotFoundError (../../packages/jest-resolve/build/index.js:868:11)
+      at Resolver._throwModNotFoundError (../../packages/jest-resolve/build/index.js:875:11)
       at Object.<anonymous> (node_modules/discord.js/src/index.js:21:12)
       at Object.require (__tests__/test.js:10:1)"
 `;

e2e/__tests__/__snapshots__/resolveNoFileExtensions.test.ts.snap

@@ -37,7 +37,7 @@ exports[`show error message with matching files 1`] = `
         |                  ^
       9 |
 
-      at Resolver._throwModNotFoundError (../../packages/jest-resolve/build/index.js:868:11)
+      at Resolver._throwModNotFoundError (../../packages/jest-resolve/build/index.js:875:11)
       at Object.require (index.js:8:18)
       at Object.require (__tests__/test.js:8:11)"
 `;

packages/jest-resolve/src/defaultResolver.ts

@@ -5,10 +5,10 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {resolve} from 'path';
 import {fileURLToPath} from 'url';
 import pnpResolver from 'jest-pnp-resolver';
 import {
+  type ResolveResult,
   ResolverFactory,
   type NapiResolveOptions as UpstreamResolveOptions,
 } from 'unrs-resolver';
@@ -20,7 +20,9 @@ export interface ResolverOptions extends UpstreamResolveOptions {
   /** List of export conditions. */
   conditions?: Array<string>;
   /** Instance of default resolver. */
-  defaultResolver: typeof defaultResolver;
+  defaultResolver: SyncResolver;
+  /** Instance of default async resolver. */
+  defaultAsyncResolver: AsyncResolver;
   /**
    * List of directory names to be looked up for modules recursively.
    *
@@ -53,7 +55,24 @@ export type AsyncResolver = (
 
 export type Resolver = SyncResolver | AsyncResolver;
 
-const defaultResolver: SyncResolver = (path, options) => {
+const handleResolveResult = (result: ResolveResult) => {
+  if (result.error) {
+    throw new Error(result.error);
+  }
+  return result.path!;
+};
+
+function baseResolver(path: string, options: ResolverOptions): string;
+function baseResolver(
+  path: string,
+  options: ResolverOptions,
+  async: true,
+): Promise<string>;
+function baseResolver(
+  path: string,
+  options: ResolverOptions,
+  async?: true,
+): string | Promise<string> {
   if (process.versions.pnp && options.allowPnp !== false) {
     return pnpResolver(path, options);
   }
@@ -76,9 +95,6 @@ const defaultResolver: SyncResolver = (path, options) => {
     /* eslint-enable prefer-const */
   } = options;
 
-  // make sure that `basedir` is an absolute path
-  basedir = resolve(basedir);
-
   modules = modules || moduleDirectory;
 
   const resolveOptions: UpstreamResolveOptions = {
@@ -95,32 +111,50 @@ const defaultResolver: SyncResolver = (path, options) => {
     unrsResolver = unrsResolver.cloneWithOptions(resolveOptions);
   } else {
     unrsResolver = new ResolverFactory(resolveOptions);
+    setResolver(unrsResolver);
   }
 
-  setResolver(unrsResolver);
-
-  let result = unrsResolver.sync(basedir, path);
-
-  if (!result.path && paths?.length) {
-    const modulesArr =
-      modules == null || Array.isArray(modules) ? modules : [modules];
-    if (modulesArr?.length) {
-      paths = paths.filter(p => !modulesArr.includes(p));
+  const finalResolver = (
+    resolve: (
+      resolver: ResolverFactory,
+    ) => ResolveResult | Promise<ResolveResult>,
+  ) => {
+    const resolveWithPathsFallback = (result: ResolveResult) => {
+      if (!result.path && paths?.length) {
+        const modulesArr =
+          modules == null || Array.isArray(modules) ? modules : [modules];
+        if (modulesArr?.length) {
+          paths = paths.filter(p => !modulesArr.includes(p));
+        }
+        if (paths.length > 0) {
+          unrsResolver = unrsResolver!.cloneWithOptions({
+            ...resolveOptions,
+            modules: paths,
+          });
+          return resolve(unrsResolver);
+        }
+      }
+      return result;
+    };
+    const result = resolve(unrsResolver!);
+    if ('then' in result) {
+      return result.then(resolveWithPathsFallback).then(handleResolveResult);
     }
-    if (paths.length > 0) {
-      unrsResolver = unrsResolver.cloneWithOptions({
-        ...resolveOptions,
-        modules: paths,
-      });
-      result = unrsResolver.sync(basedir, path);
-    }
-  }
+    return handleResolveResult(
+      resolveWithPathsFallback(result) as ResolveResult,
+    );
+  };
 
-  if (result.error) {
-    throw new Error(result.error);
-  }
+  return finalResolver((resolver: ResolverFactory) =>
+    async ? resolver.async(basedir, path) : resolver.sync(basedir, path),
+  );
+}
 
-  return result.path!;
-};
+export const defaultResolver: SyncResolver = baseResolver;
+
+export const defaultAsyncResolver: AsyncResolver = (
+  path: string,
+  options: ResolverOptions,
+) => baseResolver(path, options, true);
 
 export default defaultResolver;

packages/jest-resolve/src/resolver.ts

@@ -15,6 +15,7 @@ import defaultResolver, {
   type AsyncResolver,
   type Resolver as ResolverInterface,
   type SyncResolver,
+  defaultAsyncResolver,
 } from './defaultResolver';
 import {clearFsCache} from './fileWalkers';
 import isBuiltinModule from './isBuiltinModule';
@@ -122,6 +123,7 @@ export default class Resolver {
       return resolver(path, {
         basedir: options.basedir,
         conditions: options.conditions,
+        defaultAsyncResolver,
         defaultResolver,
         extensions: options.extensions,
         moduleDirectory: options.moduleDirectory,
@@ -142,7 +144,7 @@ export default class Resolver {
     options: FindNodeModuleConfig,
   ): Promise<string | null> {
     const resolverModule = loadResolver(options.resolver);
-    let resolver: ResolverInterface = defaultResolver;
+    let resolver: ResolverInterface = defaultAsyncResolver;
 
     if (typeof resolverModule === 'function') {
       resolver = resolverModule;
@@ -165,6 +167,7 @@ export default class Resolver {
       const result = await resolver(path, {
         basedir: options.basedir,
         conditions: options.conditions,
+        defaultAsyncResolver,
         defaultResolver,
         extensions: options.extensions,
         moduleDirectory: options.moduleDirectory,

website/versioned_docs/version-30.0/Configuration.md

@@ -1476,6 +1476,8 @@ type ResolverOptions = {
   conditions?: Array<string>;
   /** Instance of default resolver. */
   defaultResolver: (path: string, options: ResolverOptions) => string;
+  /** Instance of default async resolver. */
+  defaultAsyncResolver: (path: string, options: ResolverOptions) => Promise<string>;
   /** List of file extensions to search in order. */
   extensions?: Array<string>;
   /** List of directory names to be looked up for modules recursively. */
@@ -1491,6 +1493,8 @@ type ResolverOptions = {
 
 The `defaultResolver` passed as an option is the Jest default resolver which might be useful when you write your custom one. It takes the same arguments as your custom synchronous one, e.g. `(path, options)` and returns a string or throws.
 
+Similarly, the `defaultAsyncResolver` is the default async resolver which takes the same arguments and returns a promise that resolves with a string or rejects with an error.
+
 :::
 
 For example, if you want to respect Browserify's [`"browser"` field](https://github.com/browserify/browserify-handbook/blob/master/readme.markdown#browser-field), you can use the following resolver:
@@ -1522,25 +1526,6 @@ const config: Config = {
 export default config;
 ```
 
-By combining `defaultResolver` and `packageFilter` we can implement a `package.json` "pre-processor" that allows us to change how the default resolver will resolve modules. For example, imagine we want to use the field `"module"` if it is present, otherwise fallback to `"main"`:
-
-```js
-module.exports = (path, options) => {
-  // Call the defaultResolver, so we leverage its cache, error handling, etc.
-  return options.defaultResolver(path, {
-    ...options,
-    // Use packageFilter to process parsed `package.json` before the resolution (see https://www.npmjs.com/package/resolve#resolveid-opts-cb)
-    packageFilter: pkg => {
-      return {
-        ...pkg,
-        // Alter the value of `main` before resolving the package
-        main: pkg.module || pkg.main,
-      };
-    },
-  });
-};
-```
-
 ### `restoreMocks` \[boolean]
 
 Default: `false`