For user authentication in node using bcrypt I have the following code but i get an error when i try to post using postman api the error is "message": "Illegal arguments: string, undefined"

The data sent through the postman is

    {
       "password":"1234",
       "email":"[email protected]"
    }

I cannot find whats wrong with the code can you please help me through this.

This is the code for server.js

import express from 'express';
import userdata from './userdata.js';
import mongoose  from 'mongoose';
import userrouter from './routers/userrouter.js';
import productRouter from './routers/productrouter.js';


const app=express();

mongoose.connect(process.env.MONGODB_URL ||  'mongodb://localhost:27017/purpleshades',{
        useUnifiedTopology: true, 
        useNewUrlParser: true 
})



app.use(express.json());
app.use(express.urlencoded({ extended: true }));


app.get('/users/api/:id',(req,res)=>{
    const k=parseInt(req.params.id)
    const user1=userdata.users.find((x)=>x.uID===k)
    const cartinfo=user1.ucart
    const cartproductlist=[]
for (let i = 0; i < cartinfo.length; i  ) {
    const pid = cartinfo[i];
    const productreal = data.products.find((x) => x.id === pid );
    cartproductlist.push(productreal)   
}
    res.send(cartproductlist)
})



app.use('/api/users',userrouter)
app.use('/api/products',productRouter)
app.use((err,req,res,next)=>{
    res.status(500).send({message:err.message})
})
const port=process.env.PORT || 5000
app.listen(5000,()=>{
    console.log(`serve at http://localhost:${port}`);
})

code for userrouter.js

import express from "express";
import userdata from "../userdata.js";
import User from "../models/usermodel.js";
import expressAsyncHandler from "express-async-handler";
import bcrypt from 'bcryptjs'

const userrouter=express.Router()

userrouter.get('/seed',expressAsyncHandler( async(req,res)=>{
    const createdusers=await User.insertMany(userdata.users)
    res.send({createdusers})
}))


userrouter.post('/signin',expressAsyncHandler(async(req,res)=>{
    const user=User.findOne({email: req.body.email})
    if(user){
        if(bcrypt.compareSync(req.body.password,user.password)){
            res.send({
                _id:user._id,
                name:user.name,
                isAdmin:user.isAdmin,
            })
            return
        }
    }
    res.status(401).send({message:'invalid Email or Password'})
}))

export default userrouter

code for usermodel.js

import mongoose  from "mongoose";

const userschema=new mongoose.Schema(
    {
        name:{type:String,required:true},
        email:{type:String,required:true,unique:true},
        password:{type:String,required:true},
        isadmin:{type: Boolean,required:true ,default:false}
    },
    {
        timestamps:true
    }
)

const User=mongoose.model('User',userschema)
export default User

CodePudding user response：

The findOne function is asynchronous, so this line assigns a promise to the variable user:

const user=User.findOne({email: req.body.email})

Since a promise is truish, this proceeds to call compareSync, but the promise does not have a password property:

    if(user){
        if(bcrypt.compareSync(req.body.password,user.password)){

Await the result of the findOne to get the document instead of a promise.