{
    "error": {
        "message": "Cast to ObjectId failed for value "aaa" at path "_id" for model "Product"",
        "name": "CastError",
        "stringValue": ""aaa"",
        "kind": "ObjectId",
        "value": "aaa",
        "path": "_id"
    }
}

{
  message:"Invalid id"
}

router.get('/:productId',(req,res,next) => {
    const id = req.params.productId;
    Product.findById(id)
    .exec()
    .then(doc => {
        if (doc) {
            res.status(200).json({
                doc
            })
        } else {
            res.status(404).json({
                message:"Invalid id"
            })
        }
        console.log(doc)
    })
    .catch(err => {
        console.log(err)
        res.status(500).json({
            error: err
        })
    })
    })

const express = require('express')
const router = express.Router()
const mongoose = require('mongoose')

const Product = require('../models/products')

router.get('/',(req,res,next) => {
    res.status(200).json({
        message : 'Request'
    })
})

router.post('/',(req,res,next) => {
    const product = new Product({
        _id: new mongoose.Types.ObjectId(),
        name: req.body.name,
        price: req.body.price
    })
    product.save()
    .then((result) => {
        console.log(result)
        res.status(201).json({
            message : 'Request',
            createdProduct : result
        })
        }
    )
    .catch(err => {console.log(err)
    res.status(500).json({
        error: err
    })}
)
})

router.get('/:productId',(req,res,next) => {
    const id = req.params.productId;
    Product.findById(id)
    .exec()
    .then(doc => {
        if (doc) {
            res.status(200).json({
                doc
            })
        } else {
            res.status(404).json({
                message:"Invalid id"
            })
        }
        console.log(doc)
    })
    .catch(err => {
        console.log(err)
        res.status(500).json({
            error: err
        })
    })
    })

router.patch('/:productId',(req,res,next) => {
    const id = req.params.productId;
    if (id === 'special'){
        res.status(200).json({
            message : 'special',
            id : id
        })
    }else{
        res.status(200).json({
            message : 'not special'
        })
    }
})

router.delete('/:productId',(req,res,next) => {
    const id = req.params.productId;
    if (id === 'special'){
        res.status(200).json({
            message : 'special',
            id : id
        })
    }else{
        res.status(200).json({
            message : 'not special'
        })
    }
})

module.exports = router