How to instantiate javascript object after ajax callback? (within module design pattern)

I have something like this:

var MyModule = function() {
    // some private var
    var myVar1, myVar2;

    // some private function
    var _myPrivateFunc = function() {
        //something
    }

    // public API
    retu {
        publicFunction: function(options) {
            //something public here
        }
    }
};

var someOptions = {...};

// create MyModule instance
var test1 = new MyModule();
test1.publicFunction(someOptions);

My goal is to obtain same structure but instead of directly creating an instance of MyModule, I'd like to instantiate the object (test1) after an ajax call. Something like this:

// public API
    retu {
        publicFunction: function(options) {
            $.ajax({
                url: options.someUrl,
                type: 'POST',
                data: options.someData,
                datatype: 'json',
                success: function(data) {
                    //here I want to create an instance of MyModule
                    //with 'data' response object
                }
            });
        }
    }

Any kind of solution is accepted but remember to maintain this structure:

// create MyModule instance (wait for ajax response)
var test1 = new MyModule();
test1.publicFunction(someOptions);

That's mean I can't use the callback to obtain data and then instantiate the object.

Thanks