fixed the type issues and coverage

Author: sdangol

packages/event-handler/src/rest/Router.ts

@@ -280,11 +280,11 @@ class Router {
         ...requestContext,
         scope: options?.scope,
       });
+      const statusCode =
+        result instanceof Response ? result.status : result.statusCode;
       return handlerResultToProxyResult(
         result,
-        (result.status ??
-          result.statusCode ??
-          HttpErrorCodes.INTERNAL_SERVER_ERROR) as (typeof HttpErrorCodes)[keyof typeof HttpErrorCodes]
+        statusCode as (typeof HttpErrorCodes)[keyof typeof HttpErrorCodes]
       );
     }
   }

packages/event-handler/src/rest/errors.ts

@@ -1,3 +1,4 @@
+import type { JSONValue } from '@aws-lambda-powertools/commons/types';
 import type { HandlerResponse, HttpStatusCode } from '../types/rest.js';
 import { HttpErrorCodes } from './constants.js';
 
@@ -39,7 +40,9 @@ export abstract class ServiceError extends Error {
       statusCode: this.statusCode,
       error: this.errorType,
       message: this.message,
-      ...(this.details && { details: this.details }),
+      ...(this.details && {
+        details: this.details as Record<string, JSONValue>,
+      }),
     };
   }
 }

packages/event-handler/tests/unit/rest/Router/error-handling.test.ts

@@ -431,6 +431,33 @@ describe('Class: Router - Error Handling', () => {
     });
   });
 
+  it('handles returning an API Gateway Proxy result from the error handler', async () => {
+    // Prepare
+    const app = new Router();
+
+    app.errorHandler(BadRequestError, async () => ({
+      statusCode: HttpErrorCodes.BAD_REQUEST,
+      body: JSON.stringify({
+        foo: 'bar',
+      }),
+    }));
+
+    app.get('/test', () => {
+      throw new BadRequestError('test error');
+    });
+
+    // Act
+    const result = await app.resolve(createTestEvent('/test', 'GET'), context);
+
+    // Assess
+    expect(result).toEqual({
+      statusCode: HttpErrorCodes.BAD_REQUEST,
+      body: JSON.stringify({
+        foo: 'bar',
+      }),
+    });
+  });
+
   it('handles returning a JSONObject from the error handler', async () => {
     // Prepare
     const app = new Router();