How to pass parameters from one deferred to the next with Javascript

Extremely simplified I have the following situation:

function fxRun() {
   dtStep1().then(dtStep2);
}

with:

function dtStep1() {
    var dfd = $.Deferred(function () {
        setTimeout(function () {
            var arr = ["x","y"];
            dfd.resolve();
        }, 2000);
    });
    return dfd.promise();
}

function dtStep2() {
    var dfd = $.Deferred(function () {
        setTimeout(function () {
            //want to use arr here!
            dfd.resolve();
        }, 2000);
    });
    return dfd.promise();
    }

How do I pass variable arr that is assigned in dtStep1() to dtStep2() so I will be able to use it there? Thanks in advance!!!