changes

Author: cspotcode

src/cjs-resolve-filename-hook.ts

@@ -1,5 +1,6 @@
 import type Module = require('module');
 import type { Service } from '.';
+import { isRelativeSpecifier } from './util';
 
 /** @internal */
 export type ModuleConstructorWithInternals = typeof Module & {
@@ -19,6 +20,10 @@ interface ModuleResolveFilenameOptions {
 
 /**
  * @internal
+ *
+ * If any features of this service require patching Module._resolveFilename,
+ * then install our hook.  Logic within the hook conditionally implements
+ * multiple resolver behaviors.
  */
 export function installCommonjsResolveHookIfNecessary(tsNodeService: Service) {
   const Module = require('module') as ModuleConstructorWithInternals;
@@ -35,7 +40,7 @@ export function installCommonjsResolveHookIfNecessary(tsNodeService: Service) {
     options?: ModuleResolveFilenameOptions,
     ...rest: any[]
   ): string {
-    if (!tsNodeService.enabled())
+    function defer(this: any) {
       return originalResolveFilename.call(
         this,
         request,
@@ -44,16 +49,48 @@ export function installCommonjsResolveHookIfNecessary(tsNodeService: Service) {
         options,
         ...rest
       );
+    }
+    if (!tsNodeService.enabled())
+      return defer();
 
+    // Map from emit to source extensions
+    if (!isMain && canReplaceJsWithTsExt(tsNodeService, request, parent?.filename)) {
+      try {
+        return originalResolveFilename.call(
+          this,
+          request.slice(0, -3),
+          parent, isMain, options, ...rest
+        );
+      } catch (e) {
+        const mainFile = defer();
+        if (mainFile.endsWith('.js')) {
+          //re-resolve with configured extension preference
+          return originalResolveFilename.call(
+            this,
+            mainFile.slice(0, -3),
+            parent, isMain, options, ...rest
+          );
+        }
+        return mainFile;
+      }
+    }
     // This is a stub to support other pull requests that will be merged in the near future
     // Right now, it does nothing.
-    return originalResolveFilename.call(
-      this,
-      request,
-      parent,
-      isMain,
-      options,
-      ...rest
-    );
+    return defer();
+  }
+}
+
+function canReplaceJsWithTsExt(service: Service, request: string, parentPath?: string) {
+  if (!parentPath || service.ignored(parentPath)) return false;
+  if (isRelativeSpecifier(request) && request.slice(-3) === '.js') {
+    if (!parentPath) return true;
+    const paths = require.main?.paths || [];
+    // This logic is intending to exclude node_modules
+    for (let i = 0; i < paths.length; i++) {
+      if (parentPath.startsWith(paths[i])) {
+        return false;
+      }
+    }
+    return true;
   }
 }

src/configuration.ts

@@ -406,7 +406,6 @@ function filterRecognizedTsConfigTsNodeOptions(jsonObject: any): {
     scope,
     scopeDir,
     moduleTypes,
-    experimentalResolverFeatures,
     swc,
     experimentalResolverFeatures,
     esm,

src/index.ts

@@ -16,7 +16,6 @@ import {
   ProjectLocalResolveHelper,
   split,
   yn,
-  isRelativeSpecifier,
 } from './util';
 import { findAndReadConfig, loadCompiler } from './configuration';
 import type { TSCommon, TSInternal } from './ts-compiler-types';
@@ -26,10 +25,7 @@ import {
 } from './module-type-classifier';
 import { createResolverFunctions } from './resolver-functions';
 import type { createEsmHooks as createEsmHooksFn } from './esm';
-import {
-  installCommonjsResolveHookIfNecessary,
-  ModuleConstructorWithInternals,
-} from './cjs-resolve-filename-hook';
+import {installCommonjsResolveHookIfNecessary, ModuleConstructorWithInternals} from './cjs-resolve-filename-hook';
 
 export { TSCommon };
 export {
@@ -572,51 +568,6 @@ export function getExtensions(config: _ts.ParsedCommandLine) {
   return { tsExtensions, jsExtensions };
 }
 
-function canDropJsExt(request: string, parentPath?: string) {
-  if (isRelativeSpecifier(request) && request.slice(-3) === '.js') {
-    if (!parentPath) return true;
-    const paths = require.main?.paths || [];
-    for (let i = 0; i < paths.length; i++) {
-      if (parentPath.startsWith(paths[i])) {
-        return false;
-      }
-    }
-    return true;
-  }
-}
-
-function patchResolveFileName() {
-  const originalResolveFilename = (Module as any)._resolveFilename;
-
-  (Module as any)._resolveFilename = function (...args: any[]) {
-    const [request, parent, isMain] = args;
-    if (isMain) {
-      return originalResolveFilename.apply(this, args);
-    }
-    if (canDropJsExt(request, parent?.path)) {
-      try {
-        return originalResolveFilename.call(
-          this,
-          request.slice(0, -3),
-          ...args.slice(1)
-        );
-      } catch (e) {
-        const mainFile = originalResolveFilename.apply(this, args);
-        if (mainFile.endsWith('.js')) {
-          //re-resolve with configured extension preference
-          return originalResolveFilename.call(
-            this,
-            mainFile.slice(0, -3),
-            ...args.slice(1)
-          );
-        }
-        return mainFile;
-      }
-    }
-    return originalResolveFilename.apply(this, args);
-  };
-}
-
 /**
  * Create a new TypeScript compiler instance and register it onto node.js