gistfile1.js

function works() {
    var promise = getPromise();
    promise.then(first_success, first_error);
    promise.then(second_success, second_error);
    return promise;
}

function doesNotWork() {
    var promise = getPromise();
    promise.then(first_success, first_error).then(second_success, second_error);
    return promise;
}