Javascript Pushing elements inside a loop, doesn't affect the array outside the loop

Question

I have an empty array that I want to push items onto, inside a loop. Once outside the loop, the array losses all information

var result = [];
        users.find({}, {username: true, isOnline: true, uniq: true, _id: false}, function(err, cursor) {
            cursor.each(function(err, item) {
                result.push(item);
                console.log(result); //every iteration the array shows fine
            });

            console.log(result); //array is empty
        });

        console.log(result); //array is empty

Answer 1

It looks like you are using Mongoskin, you can use the toArray method to convert the cursor to an Array, which seems to be what you want. Check this out:

http://www.hacksparrow.com/mongoskin-tutorial-with-examples.html

db.collection('stuff').find().toArray(function(err, result) {
    if (err) throw err;
    console.log(result);
});

So your code would look like this:

var result = [];
        users.find({}, {username: true, isOnline: true, uniq: true, _id: false})
        .toArray(function(err, cursor) {
            // cursor is now an array. forEach is sync.
            cursor.forEach(function(item) {
                result.push(item);
                console.log(result); //every iteration the array shows fine
            });

            console.log(result); // Should not be empty now
            // Add more code in here, if you want to do something with
            // the result array
        });
        // Still empty, because find is async.
        // Your code should go inside of the users.find call
        // and not here
        console.log(result);

This is something you'll be dealing with a lot with node. For async code, the rest of your code must go inside of the async calls. You can keep dealing with callbacks, or use Promises, for instance.