I am trying to return the results (an array of json objects) from my get_salt_and_hash() function. I then want to use the results in another function. (In this case the length of the results array is one.)
However, after calling the get_salt_and_hash() in my other function, when I try to print the object I get undefined. I am unsure as to why, since console.log(results) in the original function works. Could someone help me out.
const get_salt_and_hash = (email) => {
const query = `SELECT p_salt, p_hash FROM USERS_TABLE WHERE email= "${email}"`;
db.query(query, (err, results) => {
if (!err) {
console.log(results);
return results[0];
} else {
throw err
}
})}
const verify_user = (email, password) => {
let result_obj = get_salt_and_hash(email);
console.log(result_obj);
// const p_hash = result_obj['p_hash'];
// const p_salt = result_obj['p_salt']
}
I suspect it has something to do with asynchronous code, since it takes time for the db query to be made, but I pretty much no nothing about async javascript, so I thought it would be better to ask others.
Thanks in advance!
You are correct that, it takes time to fetch results from db, so just promisify the query() function , so you can use await on the query() function call , I modified your code below and promisified the query().
// Not tested.
const util = require('util');
const get_salt_and_hash = async (email) => {
const query = `SELECT p_salt, p_hash FROM USERS_TABLE WHERE email= "${email}"`;
const promisifiedQuerFunction = util.promisify(db.query).bind(db);
let results = await promisifiedQuerFunction(query);
return results[0];
}
const verify_user = async (email, password) => {
let result_obj = await get_salt_and_hash(email);
console.log(result_obj);
}
You can learn how write async functions from here