feat: improve error handling for API

src/routers/api.ts

@@ -21,11 +21,20 @@ const RouterApi = Router();
  */
 const errorHandler = (res: Response, err: Error | any) => {
 	log.error(err);
+
+	// Get the status code for the Response
+	let code: number;
 	switch (err.message) {
-		case 'User not found': return res.sendStatus(404);
-		case 'Meta key already exists': return res.sendStatus(409);
-		default: return res.sendStatus(500);
+		case 'User not found':
+			code = 404; break;
+		case 'Meta key already exists':
+		case 'Username already taken':
+			code = 409; break;
+		default:
+			code = 500;
 	}
+
+	return res.status(code).type('text').send(err.message ?? err);
 };
 
 /**