Question

I am having trouble learning to use the new jQuery Deferred.

The does an ajax call and i want to return the data of the ajax call.

checkIDExists = function(id){
    var exists = false;
    $.ajax({
        data: {
            method: "idExists",
            id: id
        },
        success: function(data){
                if(data == 'true'){
                    exists = true;
                }
        }
    }).done(function(){
        return exists;
    }).fail(function(){
        return false;
    });
};

I know the problem comes in when i try to return something inside of the done() or fail() functions which doesn’t return it for the checkIdExists() function. How do i work around this?

Answer 1

Ajax itself works asynchronously, so function checkIDExists completes earlier then ajax call returns data from the server.

In your case I wouldn’t rely on return value of checkIDExists function, but I would overwrite the function using CPS approach.