rely on the result of a query to run another nodejs mysql - mysql

Question

Hey guys I have the following node code and it works fine
import express from 'express';
import connection from '../index.js'
const router = express.Router();
router.get('/allTemplates', function (req, res) {
let queryString="select count(*) as exist from users where userName='bob'";
let query = connection.query(queryString, (error, result) => {
if(error) {throw error;}
res.json(result);
})
});
module.exports = router;
what I want to do is react to this with something like
if(exists==1){error='sorry but that user already exists';} else {
queryString="insert into users (userName, email, address) values('bob', 'emailAddress#email.com', 'address')";
let query = connection.query(queryString, (error, result) => {
if(error) {throw error;}
res.json(result);
})
}
I come from a php background so this is all very new and the async of node freaks me out but I have to use it for my new job. How would I react to a result of one query and run another one based on the outcome.

Answer 1

I put the mysql library in a variable called database and I am using async await to run queries. In the database file I connect to the database and set up my variables like so:
const mysql = require("mysql");
const util = require("util");
const awsConfig = {
host: process.env.RDS_HOST,
user: process.env.RDS_USER,
password: process.env.RDS_PASSWORD,
database: process.env.RDS_DATABASE
};
const connection = mysql.createConnection(awsConfig);
connection.query = util.promisify(connection.query.bind(connection));
connection.end = util.promisify(connection.end.bind(connection));
module.exports = connection;
Than i use async await to run queries and use the results to run or not run others. like so:
let result;
let sqlStatement ="";
result = await database.query(sqlStatement);
let userExists = result[0].exist;
sqlStatement =
"SELECT COUNT(*) AS exist FROM user where userName=" +
database.escape(req.body.userName);
if(userExists==0){
result = await database.query("INSERT INTO user SET ?", [req.body]);
}
hope this helps someone else