Variable not being changed inside callback

Question

let dbResult

//insert marker into db
await pool.query(
    'INSERT INTO markers (title, description, creator, active) VALUES ($1, $2, $3, $4) RETURNING *',
    [title, description, creator, active],
    (error, results) => {
        if (error) {
            throw error
        }
        dbResult = results;
    });

console.log(dbResult)

Not really sure why but the dbResult variable is not being changed. I'm not very experienced with JavaScript, can anyone explain why this is happening.

score 1 · Answer 1 · answered Jul 27 '22 at 18:29

1

You have to log it when it is changed:

let dbResult

//insert marker into db
await pool.query(
    'INSERT INTO markers (title, description, creator, active) VALUES ($1, $2, $3, $4) RETURNING *',
    [title, description, creator, active],
    (error, results) => {
        if (error) {
            throw error
        }
        dbResult = results;
        console.log(dbResult)
    });

This is because the callback function (error, results) => ... gets triggered after the line console.log(dbResult) and so you are printing out the outdated value.

You might want to do some research on callback functions and async/await in JavaScript to get a better understanding.

answered Jul 27 '22 at 18:29

David Callanan

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The await waits for the query call but not the callback, of course. That makes sense. – Eduardo Jul 27 '22 at 18:53
Yep. It's an unusual combination to mix `await` and a callback function. – David Callanan Jul 27 '22 at 18:55
1

Yeah, my proper solution does not use a callback at all, thx. – Eduardo Jul 27 '22 at 18:59

Variable not being changed inside callback

1 Answers1