Async series with node-mysql output to array

Question

I would like to store result from mysql query in an array ( docAutocomplete) and after all the query completed I wanted to see the final array. I am using async series for this purpose. The issue is the array doesn't print anything as it looks like doesn't have any data at the function(err,results).

var mysql = require('mysql'),
async = require("async");
var connection = mysql.createConnection({
host: 'xx',
user: 'xx',
password: 'xx',
database: 'xx'
multipleStatements: true
});
var docAutocomplete = [];

async.series([

    function(callback) {
        connection.connect();


        connection.query('select x from a; select b from a', function(err, rows, fields) {
            if (err) throw err;

            for (var i = 0; i < rows[0].length; i++) {

                docAutocomplete.push({
                    " First Name": rows[0][i].x


                })
            }
            for (var i; i < rows[1].length; i++) {

                docAutocomplete.push({
                    "Last Name": rows[1][i].b

                })
            }





        });
        callback(null, 'one');

    },
    function(callback) {

        connection.end();

        callback(null, 'two');
    }
],
function(err, results) {
    console.log(results);
    console.log(JSON.stringify(docAutocomplete));

});

Current output is something like below;

[ 'one', 'two' ]
[]  // value of docAutocomplete array. Should have something here First Name and  Last name

Answer 1

connection.query is asynchronous, so the first callback is called before the query is finished. You should call your first callback only when the suery has terminated, like this :

// ...
function(callback) {
    connection.connect();

    connection.query('select x from a; select b from a', function(err, rows, fields) {
        // ...

        callback(null, 'one'); // HERE
    });
    // NOT HERE
},
// ...