send error if user already exist

src/api/auth/login.ts

@@ -13,7 +13,7 @@ const login = async (req: Request, res: Response) => {
     }
     const isValid = await comparePassword(userInfo.password, user.password);
     if (!isValid) {
-      return res.status(401).send('Invalid password');
+      return res.status(401).send({ error: 'Invalid password' });
     }
     return res.status(200).send(user);
   } catch (error) {

src/api/auth/signup.ts

@@ -1,15 +1,18 @@
 import { newUser } from '@/controller/UserController';
-import UserModel from '@/models/UserModel';
+import { User } from '@/models/UserModel';
 import { hashPassword } from '@/controller/AuthController';
-import { User } from '@prisma/client';
 import { Request, Response } from 'express';
+import { User as PrismaUser } from '@prisma/client';
 
 const signup = async (req: Request, res: Response) => {
   try {
-    UserModel.parse(req.body);
     req.body.password = await hashPassword(req.body.password);
-    const user: User = req.body;
-    const prismaUser = await newUser(user);
+    const user: User = User.parse({ ...req.body });
+    const prismaUser: PrismaUser | null = await newUser(user);
+    if (!prismaUser) {
+      return res.status(400).send({ error: 'User already exists' });
+    }
+
     return res.status(200).send(prismaUser);
   } catch (error) {
     return res.status(500).send(error);

src/controller/UserController.ts

@@ -1,4 +1,5 @@
-import { PrismaClient, User } from '@prisma/client';
+import { PrismaClient } from '@prisma/client';
+import { User } from '@/models/UserModel';
 
 const prisma = new PrismaClient();
 
@@ -12,12 +13,39 @@ const getUser = (email: string) => {
   return user;
 };
 
-const newUser = (user: User) => {
-  const prismaUser = prisma.user.create({
-    data: user,
+const isUserExist = (email: string) =>
+  prisma.user
+    .findUnique({
+      where: {
+        email,
+      },
+    })
+    .then((user) => {
+      if (user) {
+        return true;
+      }
+      return false;
+    })
+    .catch((error) => {
+      throw error;
+    });
+
+const newUser = async (user: User) => {
+  const userExist: Boolean = await isUserExist(user.email);
+  if (userExist) {
+    return null;
+  }
+  const newUser = await prisma.user.create({
+    data: {
+      email: user.email,
+      password: user.password,
+      firstName: user.firstName,
+      lastName: user.lastName,
+      role: 'USER',
+    },
   });
 
-  return prismaUser;
+  return newUser;
 };
 
 export { getUser, newUser };