Issue on asynchronous implementation in NodeJS with Sequelize - node.js

Question

I have a scenario where the API will accept the request body as below and I have failed to achieve asynchronous operation. The scenario is the API should only accept the paid amount of the particular item that has not submitted more than the existing balance which has been stored in the database.
{
"items": [
{
"itemId": "3c6d9287-a247-4852-b168-29f766e073fb",
"paidAmount": 5
},
{
"itemId": "8f3ebe13-b4dd-4b5c-887c-9663b29065cd",
"paidAmount": 5.80
}
]
}
The expected execution flow will be:
Compare the body request with the existing data from the database.
Perform the subtraction outstandingBlc (which handled by sequelize function) and paidamount of the body request.
If the substraction value is less than 0, the API should then return an error message back to the caller. Otherwise, it will continually perform the subsequent looping.
I have encountered any issue to capture the final value of the allAccepted variable (which shown in the last 3 line of the below code) after a sequence of execution inside the looping.
var data = req.body;
var items = data.items;
var total = items.map(itm =>{ return itm.paidAmount; }).reduce((a, b) => a + b, 0).toFixed(2);
var blc = 0.00;
const balance = await checkBalance(req,res);
if (balance != null){
blc = balance;
}
if (blc < total){
return res.status(403).json({error:"Insufficient balance to complete the payment!"});
}
var allAccepted = false;
Promise.all(items.map(v=>{
OrderItemTransaction.findOne({
where:{itemId:v.itemId},
attributes: [
[db.Sequelize.literal('(OrderItem.unitPrice - SUM(paidAmount))'), 'outstandingBlc']
],
include:[{
model: OrderItem,
on: {
'id': { [Op.eq]: db.sequelize.col('OrderItemTransaction.itemId') }
},
required: true
}],
raw:true
}).then(itemInfo=>{
if (!itemInfo){
return void res.status(404).json({error:"Invalid item Id"});
}
else{
const reqPaidAmount = v.paidAmount;
const outstandingBalance = itemInfo.outstandingBlc;
console.log(reqPaidAmount +"|" + outstandingBalance);
if (outstandingBalance - reqPaidAmount < 0){
allAccepted = false;
return res.status(403).json({error:`Cannot complete payment for ${v.itemId} because paid amount is ${reqPaidAmount} and outstanding balance is ${outstandingBalance}`})
}
else{
allAccepted = true;
}
}
}).catch(err=>{
console.log(err);
return res.status(500).json({error:err.message});
});
}));
console.log(allAccepted);
if (allAccepted == true){
return res.status(200).json({total:total,blc:blc});
}

Answer 1

Last 3 lines of code doesn't wait till the execution of promise.all
Add then block as below.
Promise.all(
items.map(v => {
// your db operations code
})
).then(promiseAllResult => {
if (allAccepted == true) {
return res.status(200).json({
total: total,
blc: blc
});
}
})