Mysql NodeJs syncronous queries - mysql

Question

Thank you for the answer,
I did that : i used "sync-mysql" :
but now its very very slow...
Maybe i could do the same code using Mysql NPM
Do you know how my code must look like if I want to use asyncronous function and doing the same thing as below ? It will help me a lot :)
I have almost finished my project and I only have this function left
const customer_booked = []
customer_booked[0] = []
customer_booked[1] = []
let sql = "SELECT * " +
"FROM customer as C " +
"WHERE customer_reference REGEXP '^[c]i*' "
if (filters[0].value.length){
sql += "AND C.customer_name LIKE '%" + filters[0].value + "%' "
}
if (filters[3].value.length){
sql += "LIMIT " + filters[3].value
}
var result = connection.query(sql);
const customers = [];
const booked = connection.query('SELECT cr.customer_id, a.codeAgent ' +
'FROM customer_reservation as cr ' +
'INNER JOIN agent as a ' +
'ON a.id = cr.agent_id')
booked.forEach(customer_booking => {
customer_booked[0].push(customer_booking.customer_id)
customer_booked[1].push(customer_booking.codeAgent)
});
result.forEach( customer => {
var months;
let d1 = new Date(customer.last_order);
let d2 = new Date();
months = (d2.getFullYear() - d1.getFullYear()) * 12;
months -= d1.getMonth() + 1;
months += d2.getMonth();
months = months <= 0 ? 0 : months;
if (customer_booked[0].includes(customer.customer_id)){
let code_agent_index = customer_booked[0].indexOf(customer.customer_id)
customer.available = 'booked'
customer._rowVariant = 'warning'
customer.agent_code = customer_booked[1][code_agent_index]
}
else if (months >= 12){
customer.available = 'available'
customer._rowVariant = 'success'
} else {
customer.available = 'notAvailable'
customer._rowVariant = 'danger'
}
let sql2 = "SELECT * " +
"FROM customer_addresses AS CA " +
"WHERE CA.customer_id = " + customer.id
customer.addresses = connection.query(sql2)
customers.push(customer);
//customers[customers.length].push()
})
callback(false, result)

Answer 1

You can use node.js async/await using IIFE, like this:
(async() => {
const users = await getUsers();
for(const user of users){
user.addresses = await getAddresses(user.id);
// your other code just translated to JS.
}
return users;
})()
So, the main idea is to await your async code.
For example we use IIFE (Immediately Invoked Function Expression) to access needed async/await and for tests.
In real code you should name functions with keyword async
Here is nice tutorials which could explain how to use async/await 1, 2