MongoDB Update field data - node.js

Question

How can i used db.findAndUpdate table user and change my balance from previous amount to newer?
i have try to get balance and the result it show nothing, now i'm confuse to write in findAndUpdate. here's my code:
api:
app.post('/api/account/transfer', (req, res, next) => {
const { body } = req;
const {
sender,
receiver,
amount,
user,
balance,
} = body;
if (!sender) {
return res.send({
success: false,
message: 'Error: Sender cannot be blank!'
});
}
if (!receiver) {
return res.send({
success: false,
message: 'Error: Receiver cannot be blank!'
});
}
if (!amount) {
return res.send({
success: false,
message: 'Error: Fill Amount!'
});
} else if(balance < amount || balance == 0) {
return res.send({
success: false,
message: 'Insufficient funds!'
});
}
//save the new transaction
const newTransaction = new Transaction();
newTransaction.sender = sender;
newTransaction.receiver = receiver;
newTransaction.amount = amount;
newTransaction.save( (err, transaction) => {
if(err) {
return res.send({
success: false,
message: 'Error: Server error.'
});
}else{
return res.send({
success: true,
message: 'Transfer Success!'
});
}
});
//update user balance
User.findOneAndUpdate({
});
and here's the screenshoot:
so what i want is, if i'm as a receiver my balance will be increase.

Answer 1

Try this, the findOneAndUpdate operation does not wait for save operation to complete.
app.post('/api/account/transfer', (req, res, next) => {
const {
body
} = req;
const fields = ['sender', 'receiver', 'amount', 'balance'];
fields.forEach((field) => {
if (!body[field]) {
return res.send({
success: false,
message: 'Error: ' + field + ' cannot be blank!'
});
}
})
if (body.balance < body.amount || body.balance == 0) {
return res.send({
success: false,
message: 'Insufficient funds!'
});
}
//save the new transaction
let newTransaction = new Transaction();
// newTransaction = Object.assign(newTransaction, body); // If you want to copy all params from body to newTransaction
newTransaction.sender = body.sender;
newTransaction.receiver = body.receiver;
newTransaction.amount = body.amount;
newTransaction.save((err, transaction) => {
if (err) {
return res.send({
success: false,
message: 'Error: Server error.'
});
} else {
//update user balance
User.findOneAndUpdate({
/*query*/
}, {
/*body*/
}, (err, data) => {
if (err)
return res.send({
success: false,
message: 'Error: Server error.'
});
return res.send({
success: true,
message: 'Transfer Success!'
});
});
}
});
});