How do i update in MongoDB with Node.JS - node.js

Question

i have this code i am trying to write, the code is supposed to update the balance in MongoDB after properly computing the balance. The challenge is , it does not, it properly computes the balance, but updating the column for the user, it does not update. Looking out to see where and how to update the balances only I have not seen anything to help.
My code is Looking thus :
const router = require("express").Router();
const User = require("../models/User");
const bcrypt = require("bcrypt");
const jwt = require("jsonwebtoken");
router.post("/update-balance/:email", async (req, res) => {
try {
if (
!req.headers.authorization ||
!req.headers.authorization.startsWith("Bearer ") ||
!req.headers.authorization.split(" ")[1]
) {
return res.status(422).json({ message: "Please Provide Token!" });
}
const amount = parseInt(req.body.amount);
const user = await User.find({ email: req.params.email });
const balance = parseInt(user[0].balance);
//return balance;
//console.log(balance);
const total_amt = amount + balance;
//console.log(total_amt);
// update Balance
const wallet_user = new User();
try{
await wallet_user.updateOne({email : req.params.email}, {$set: {balance: total_amt}});
}catch(err){
console.log(err);
}
return res.send({ error: false, message: "OK" });
} catch (error) {
res.status(404).json({ message: error.message });
}
});
module.exports = router;
What Am I suppose to do that i am not doing rightly, kindly help.
The code above shows What I have attempted..

Answer 1

You can use $inc:
router.post('/update-balance/:email', async (req, res) => {
try {
if (
!req.headers.authorization ||
!req.headers.authorization.startsWith('Bearer ') ||
!req.headers.authorization.split(' ')[1]
) {
return res.status(422).json({ message: 'Please Provide Token!' });
}
const amount = parseInt(req.body.amount);
try {
await User.findOneAndUpdate(
{ email: req.params.email },
{ $inc: { balance: amount } }
);
} catch (err) {
console.log(err);
}
return res.send({ error: false, message: 'OK' });
} catch (error) {
res.status(404).json({ message: error.message });
}
});