I saw a very similar problem like this on stackoverflow but the answer didn’t solve my problem. I am receiving an error apparently. I have created a post request in thunderclient in VS Code.

The first one runs fine but then the next ones

enter image description here

have issue

(https://i.sstatic.net/jy2LVl0F.png)

and show this error:

enter image description here

This is my code – I tried changing the unique:false in the code and figuring out what to do but nothing works. (https://i.sstatic.net/XI0M1aCc.png)

const port = 4000;
const express = require('express');
const app = express();
const mongoose = require('mongoose');
const jwt = require('jsonwebtoken');
const multer = require('multer');
const path = require('path');
const cors = require('cors');
const { error } = require('console');
const { type } = require('os');
const { json } = require('express');

// Connect cors to port  
app.use(express.json());
app.use(cors());

// Initialise database connection with mongoDB
mongoose.connect("mongodb+srv://aryankap:[email protected]/e-commerce");

// API creation

app.get("/", (req,res)=>{
    res.send("Express App is Running")
})

// Image Storage Engine

const storage = multer.diskStorage({
    destination: './upload/images',
    filename:(req,file,cb)=>{
        return cb(null, `${file.fieldname}_${Date.now()}${path.extname(file.originalname)}`)
    }
})

const upload = multer({storage:storage})

// Creating Upload Endpoint for images
app.use('/images',express.static('upload/images'))
app.post("/upload",upload.single('product'),(req,res)=>{
   res.json({
    success:1,
    image_url:`http://localhost:${port}/images/${req.file.filename}`
   })
})


// Schema for Creating Products

const Product = mongoose.model("Product",{
    id:{
        type:Number,
        required:true,
    },
    name:{
        type:String,
        required:true,
    },
    image:{
        type:String,
        required:true,
    },
    category:{
        type:String,
        required:true,
    }, 
    new_price:{
        type:Number,
        required:true,
    },
    old_price:{
        type:Number,
        required:true,
    },
    date:{
        type:Date,
        default:Date.now,
    },
    available:{
        type:Boolean,
        default:true,
    },
    })


app.post('/addproduct',async (req,res)=>{
        let products = await Product.find({});
        let id;
        if(products.length>0)
            {
                let last_product_array = products.slice(-1);
                let last_product = last_product_array[0];
                id = last_product.id+1;
            }
            else{
                id=1;
            }
    const product = new Product({
        id:id,
        name:req.body.name,
        image:req.body.image,
        category:req.body.category,
        new_price:req.body.new_price,
        old_price:req.body.old_price,
    });
    console.log(product);
    await product.save();
    console.log("Product Added Successfully");
    res.json({
        success:true,
        name:req.body.name,
    })
})

// Creating API for deleting products

app.post('/removeproduct',async (req,res)=>{
     await Product.findOneAndDelete({id:req.body.id});
     console.log("Removed");
     res.json({
        success:true,
        name:req.body.name, 
     })
})

// Creating API for getting all products
app.get('/allproducts',async (req,res)=>{
     let products = await Product.find({});
     console.log("All Products Fetched");
     res.send(products);
})

// Schema Creation for User model

const Users = mongoose.model('Users', {
    name:{
        type:String,
    },
    email:{
        type:String,
        unique:true,
    },
    password:{
        type:String,
    },
    cartData:{
        type:Object,
    },
    date:{
        type:Date,
        default:Date.now,
    }
})

// creating endpoint for user registration
app.post('/signup',async (req,res)=>{

    let check = await Users.findOne({email:req.body.email});
    if (check) {
        return res.status(400).json({success:false,errors:"Account already exists with this email"})
    }
    let cart = {};
    for (let i = 0; i < 300; i++) {
        cart[i]=0;
        
    }
    const user = new Users({
        name:req.body.username,
        emai:req.body.email,
        password:req.body.password,
        cartData:cart,
    })

    await user.save();

    const data = {
        user:{
            id:user.id
        }
    }

    const token = jwt.sign(data,'secret_ecom');
    res.json({success:true,token})
})

app.listen(port,(error)=>{
    if (!error) {
      console.log("Server is running on port: "+port)
    }
    else 
    {
        console.log("Error: "+error)
    }
})

These are the thunderclient requests:

Signup request 1

Upload Request

Add Product request

All Products request(This one is using GET all others are using POST)

And lastly the remove product request

I couldn’t add screenshots for all the requests all stackoverflow won’t let me due to low reputation