error while using deleteOne in app.delete function in Node.js - node.js

Question

** trying to use the app.delete and trying to delete document from mondo db using delete one...it keep throwing errror. how to solve this error ? **
``` require('dotenv').config()
const express = require('express')
const app = express()
const PORT = process.env.PORT || 5001
const connectDB = require('./config/db')
const errorHandler = require('./middleware/error')
const Product =require('./models/product')
const cors = require('cors')
// Connect DB
connectDB()
// Middleware
app.use(cors())
app.use(express.json())
app.use('/auth', require('./routes/authRoutes'))
app.use('/admin', require('./routes/adminRoutes'))
app.use('/customer', require('./routes/customerRoutes'))
app.use('/staff', require('./routes/staffMemberRoutes'))
// error handler - should be *last* piece of middleware
app.use(errorHandler)
app.get('/all-products', (req, res) => {
Product.find({}, (error, posts) => {
if(error) {
res.json({error: 'Unable to fetch products!'})
} else {
res.json(posts)
}
})
})
app.post ('/add-products',(req,res) =>{
console.log("add-products has been fired")
const imageurl = req.body.imageurl
const title = req.body.title
const description = req.body.description
const rate = req.body.rate
const category = req.body.category
const subcategory = req.body.subcategory
let product = new Product({
imageurl: imageurl,
title: title,
description: description,
rate: rate,
category: category,
subcategory: subcategory,
})
product.save((error) => {
if(error) {
res.json({error: 'Unable to save the product!'})
} else {
res.json({success: true, message: 'New product Saved'})
}
})
})
app.delete('/product/:productId', (req, res) => {
const productId = req.params.productId
Product.deleteOne({
_id: productId
}, (error, result) => {
if(error) {
res.json({error: 'Unable to delete product'})
} else {
res.json({success: true, message: 'Product deleted successfully!'})
}
})
})
app.put('/update-product/:productId', (req, res) => {
const productId = req.params.productId
const imageurl = req.body.imageurl
const title = req.body.title
const description = req.body.description
const rate = req.body.rate
const category = req.body.category
const subcategory = req.body.subcategory
const updatedProduct = {
imageurl: imageurl,
title: title,
description: description,
rate: rate,
category: category,
subcategory: subcategory,
}
Product.findByIdAndUpdate(productId, updatedProduct, (error, result) => {
if(error) {
res.json({error: 'Unable to updated the Product'})
} else {
res.json({success: true, message: 'Product updated successfully!'})
}
})
})
const server = app.listen(PORT, () => {
console.log(`Server running on port ${PORT}`)
})
// makes giant server errors concise and simple to read
process.on('unhandledRejection', (err, promise) => {
console.log(`Logged Error: ${err}`)
server.close(() => process.exit(1))
})```

Answer 1

if(error) {
res.json({error: 'Unable to delete product'})
}
In this line, replace res.json with:
res.json({error})
And then comment here the output (error message on the console)