Return showing undefined javascript

Question

im writing a discord bot to check points from a database then return them. This is my code at the moment.

function userCheck(id, name) {
        date = new Date().toISOString().slice(0, 19).replace('T', ' ');
        con.query("SELECT id FROM users WHERE id = "+id, function (err, row) {
            if (!(row && row.length) ) {
                    con.query("INSERT INTO `users` (id,name,rank,points,signup) VALUES ('"+id+"', "+name+", '0', '0' , '"+date+"')"), function (err, result, fields){
                        if (err) throw err;
                    }
            }else{
                //fine
            }
    });
    }


    function checkPoints(user){
        id = user.id;
        name = con.escape(user.username);

        userCheck(id, name);
        console.log("SELECT points FROM users WHERE id = "+id);
        con.query("SELECT points FROM users WHERE id = "+id, function (err, result, fields){
            return result[0].points;
        });
    }

My code which calls these functions is this: return message.author.send(checkPoints(message.author));

This makes discordjs error as it is trying to return an empty message. This means my functions arent returning right. Ive look at this over and over its probably just a simple fix but I cant see it.

Thanks in advance

function checkPoints doesn't have a return statement, therefore returns undefined — Bravo
– Bravo, Commented Oct 29, 2018 at 11:31
Not familiar with the API, but I'm going to take a guess that con.query is an asynchronous function and you're returning in a callback function. The function ends before your results will ever come in. You need to use a promise or async/await. — msg45f
– msg45f, Commented Oct 29, 2018 at 11:32
@Bravo it does return? after the query. It also checks before the query if the user is in the database. — Kong
– Kong, Commented Oct 29, 2018 at 11:35
no, it does not ... that return is in the function (err, result, fields){ function ... return doesn't return from all enclosing functions — Bravo
– Bravo, Commented Oct 29, 2018 at 11:36

Bravo · Accepted Answer · 2018-10-29 11:37:18Z

function checkPoints(user){ doesn't return anything i.e. same as return undefined

Since con.query is asynchronous - the simplest fix is to use a callback, like so

function checkPoints(user, cb){
    id = user.id;
    name = con.escape(user.username);

    userCheck(id, name);
    console.log("SELECT points FROM users WHERE id = "+id);
    con.query("SELECT points FROM users WHERE id = "+id, function (err, result, fields){
        cb(result[0].points);
    });
}

checkPoints(message.author, function(result) {
    message.author.send(result);
});

or, use Promise

function checkPoints(user){
    return new Promise(function(resolve, reject) {
        id = user.id;
        name = con.escape(user.username);

        userCheck(id, name);
        console.log("SELECT points FROM users WHERE id = "+id);
        con.query("SELECT points FROM users WHERE id = "+id, function (err, result, fields){
            if(err) return reject(err);
            resolve(result[0].points);
        });
    });
}

checkPoints(message.author)
.then(function(result) {
    message.author.send(result);
});

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