How to access variable outside of query block?

Question

I want to use the for loop outside of the query but it is printing empty.

sql = 'SELECT * FROM people';
let currMarker = [];

db.all(sql, [], (err,rows) => {
    if (err) return console.error(err.message);
    
    currMarker = rows;

    for (let i = 0; i < currMarker.length; i++) {
        console.log(currMarker[i].name);
        console.log(currMarker[i].username);
    }
});

I want to use it like :

sql = 'SELECT * FROM people';
let currMarker = [];

db.all(sql, [], (err,rows) => {
    if (err) return console.error(err.message);
    
    currMarker = rows;
});

for (let i = 0; i < currMarker.length; i++) {
    console.log(currMarker[i].name);
    console.log(currMarker[i].username);
}

Does this answer your question? [How do I return the response from an asynchronous call?](https://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call) — Samathingamajig, Nov 12 '22 at 07:29
You can't use it outside the request this way. You've to use promises or async/await. — Araf, Nov 12 '22 at 07:30

score 0 · Accepted Answer · edited Nov 14 '22 at 11:05

Here's a solution.

sql = 'SELECT * FROM people';

let currMarker = [];

const queryFunc = () =>{
    return new Promise((resolve, reject)=>{
        db.all(sql, [], (err,rows) => {
            if (err) return console.error(err.message);
            
            currMarker = rows;
            resolve();
        });
    });
};

queryFunc().then((val)=>{
    for (let i = 0; i < currMarker.length; i++) {
        console.log(currMarker[i].name);
        console.log(currMarker[i].username); 
    }
});

How to access variable outside of query block?

1 Answers1