Fix TypeScript import resolution for extensionless imports

Automatically add .js extension to relative imports that don't have a standard module extension. This fixes the ERR_MODULE_NOT_FOUND error when TypeScript files import other files without specifying an extension (e.g., import from "./abstract.helper" instead of "./abstract.helper.js").

The transpiler now:
- Detects imports without standard extensions (.js, .mjs, .cjs, .json, .node)
- Adds .js extension automatically for ESM compatibility
- Handles both transpiled TypeScript files (rewrites to .temp.mjs) and regular JS files

Co-authored-by: kobenguyent <7845001+kobenguyent@users.noreply.github.com>

Author: Copilot

lib/utils/typescript.js

@@ -168,6 +168,7 @@ const __dirname = __dirname_fn(__filename);
       /from\s+['"](\..+?)(?:\.ts)?['"]/g,
       (match, importPath) => {
         let resolvedPath = path.resolve(fileBaseDir, importPath)
+        const originalExt = path.extname(importPath)
 
         // Handle .js extension that might be .ts
         if (resolvedPath.endsWith('.js')) {
@@ -181,6 +182,8 @@ const __dirname = __dirname_fn(__filename);
             }
             return `from '${relPath}'`
           }
+          // Keep .js extension as-is (might be a real .js file)
+          return match
         }
 
         // Try with .ts extension
@@ -197,6 +200,18 @@ const __dirname = __dirname_fn(__filename);
           return `from '${relPath}'`
         }
 
+        // If the import doesn't have a standard module extension (.js, .mjs, .cjs, .json)
+        // add .js for ESM compatibility
+        // This handles cases where:
+        // 1. Import has no real extension (e.g., "./utils" or "./helper")
+        // 2. Import has a non-standard extension that's part of the name (e.g., "./abstract.helper")
+        const standardExtensions = ['.js', '.mjs', '.cjs', '.json', '.node']
+        const hasStandardExtension = standardExtensions.includes(originalExt.toLowerCase())
+        
+        if (!hasStandardExtension) {
+          return match.replace(importPath, importPath + '.js')
+        }
+        
         // Otherwise, keep the import as-is
         return match
       }

test/data/typescript-support/MaterialComponentHelper.ts

@@ -0,0 +1,15 @@
+// TypeScript custom helper that imports another TypeScript file
+// Testing import without extension (should work after fix)
+import { AbstractHelper, HelperUtils } from "./abstract-helper";
+
+class MaterialComponentHelper extends AbstractHelper {
+  customMethod(): string {
+    return HelperUtils.formatMessage('Material component helper loaded');
+  }
+
+  async clickButton(selector: string): Promise<void> {
+    console.log(`Clicking button: ${selector}`);
+  }
+}
+
+export default MaterialComponentHelper;

test/data/typescript-support/abstract-helper.ts

@@ -0,0 +1,16 @@
+// Abstract helper base class for testing imports
+export abstract class AbstractHelper {
+  protected config: any;
+
+  constructor(config?: any) {
+    this.config = config;
+  }
+
+  abstract customMethod(): string;
+}
+
+export class HelperUtils {
+  static formatMessage(msg: string): string {
+    return `[Helper] ${msg}`;
+  }
+}

test/unit/container_test.js

@@ -368,5 +368,23 @@ describe('Container', () => {
       expect(helper.customMethod()).to.eql('TypeScript helper loaded successfully')
       expect(helper.asyncCustomMethod).to.be.a('function')
     })
+
+    it('should load TypeScript helper that imports another TypeScript file without extension', async () => {
+      const tsHelperPath = path.join(__dirname, '../data/typescript-support/MaterialComponentHelper.ts')
+      await container.create({
+        helpers: {
+          MaterialComponentHelper: {
+            require: tsHelperPath,
+          },
+        },
+      })
+      await container.started()
+
+      const helper = container.helpers('MaterialComponentHelper')
+      expect(helper).to.be.ok
+      expect(helper.customMethod).to.be.a('function')
+      expect(helper.customMethod()).to.eql('[Helper] Material component helper loaded')
+      expect(helper.clickButton).to.be.a('function')
+    })
   })
 })