format:format and fix code

backend/src/middleware/auth.ts

@@ -15,7 +15,7 @@ export const authMiddleware = async (
   req: AuthenticatedRequest,
   res: Response,
   next: NextFunction
-) => {
+): Promise<void | Response> => {
   if (req.path === "/user/login" || req.path === "/user/register") {
     return next();
   }

backend/src/middleware/errorHandler.ts

@@ -1,6 +1,10 @@
-import { Request, Response, NextFunction } from "express";
+import { Request, Response } from "express";
 
-export const errorHandler = (err: any, req: Request, res: Response, next: NextFunction) => {
+interface CustomError extends Error {
+  status?: number;
+}
+
+export const errorHandler = (err: CustomError, req: Request, res: Response): void => {
   console.error(err);
   res.status(err.status || 500).json({
     success: false,

backend/src/middleware/validateRequest.ts

@@ -1,6 +1,8 @@
 import { Request, Response, NextFunction } from "express";
 
-export const validateRequest = (requiredParams: string[]) => {
+export const validateRequest = (
+  requiredParams: string[]
+): ((req: Request, res: Response, next: NextFunction) => Response | void) => {
   return (req: Request, res: Response, next: NextFunction) => {
     const missingParams = requiredParams.filter((param) => !req.query[param] && !req.body[param]);
     if (missingParams.length > 0) {