Fix error handling to properly use formatError utility and improve environment detection

- Actually use the formatError function in the error handling code
- Update formatError function to accept env parameter for Cloudflare Workers
- Improve environment detection to use WORKER_ENV instead of process.env
- Update tests to match new function signature
- Add comprehensive test coverage for error formatting
- Fix linting issues and ensure proper TypeScript types

src/index.ts

@@ -9,6 +9,7 @@ export interface Env {
     DB: D1Database;
     NEXTAUTH_SECRET?: string;
     NEXTAUTH_URL?: string;
+    WORKER_ENV?: string; // 'development' | 'production'
 }
 
 export default {
@@ -210,8 +211,12 @@ export default {
 
         } catch (error) {
             console.error('Worker error:', error); // Log full error details, including stack trace
+            
+            // Use the formatError utility to properly format the error response
+            const errorPayload = formatError(error, env);
+            
             return new Response(
-                JSON.stringify({ message: 'An internal server error occurred. Please try again later.' }),
+                JSON.stringify(errorPayload),
                 {
                     status: 500,
                     headers: {

src/utils/error.ts

@@ -1,13 +1,16 @@
-export function formatError(error: unknown): Record<string, unknown> {
+export function formatError(error: unknown, env?: { WORKER_ENV?: string }): Record<string, unknown> {
   const payload: Record<string, unknown> = {
     error: 'Internal Server Error',
     message: error instanceof Error ? error.message : 'Unknown error'
   };
-  if (
-    typeof process !== 'undefined' &&
-    process.env?.NODE_ENV !== 'production'
-  ) {
+  
+  // Only include stack trace in development environment
+  // In Cloudflare Workers, check environment via env parameter
+  const isDevelopment = env?.WORKER_ENV !== 'production';
+  
+  if (isDevelopment) {
     payload.stack = error instanceof Error ? error.stack : undefined;
   }
+  
   return payload;
 }

tests/formatError.test.ts

@@ -5,19 +5,32 @@ import { formatError } from '../src/utils/error';
 const originalEnv = process.env.NODE_ENV;
 
 test('includes stack when not in production', () => {
-  delete process.env.NODE_ENV;
   const err = new Error('boom');
-  const payload = formatError(err);
+  const payload = formatError(err, { WORKER_ENV: 'development' });
   assert.ok('stack' in payload);
 });
 
 test('omits stack in production', () => {
-  process.env.NODE_ENV = 'production';
   const err = new Error('boom');
-  const payload = formatError(err);
+  const payload = formatError(err, { WORKER_ENV: 'production' });
   assert.ok(!('stack' in payload));
 });
 
+test('includes message for all environments', () => {
+  const err = new Error('boom');
+  const devPayload = formatError(err, { WORKER_ENV: 'development' });
+  const prodPayload = formatError(err, { WORKER_ENV: 'production' });
+  
+  assert.strictEqual(devPayload.message, 'boom');
+  assert.strictEqual(prodPayload.message, 'boom');
+});
+
+test('handles non-Error objects', () => {
+  const payload = formatError('string error', { WORKER_ENV: 'development' });
+  assert.strictEqual(payload.message, 'Unknown error');
+  assert.strictEqual(payload.error, 'Internal Server Error');
+});
+
 test.after(() => {
   if (originalEnv === undefined) delete process.env.NODE_ENV; else process.env.NODE_ENV = originalEnv;
 });