return the value from a promise/ajax call with jquery

Question

var viewmodel = service.createCustomer(); is the way I call the requirejs module.

How do I have to create a deferred object that my createCustomer returns the CreateCustomerViewModel which is created inside the service call?

define(['viewmodels/CreateCustomerViewModel'],function (CreateCustomerViewModel) {

    function createCustomer() {
        $.getJSON('Customer/Create')
         .done(function (response) {
             return new CreateCustomerViewModel(response);
         })
         .fail(function (error) {
             alert(error);
         });
    }   

    return {        
        createCustomer: createCustomer        
    };
});

Answer 1

1. You must use .then() instead of .done() to modify the payload.
2. You should let your createCustomer method return the modified payload.

Your module definition becomes:

function createCustomer() {
    return $.getJSON('Customer/Create')
        .then(function (response) {
            return new CreateCustomerViewModel(response);
        });
}

return {
    createCustomer: createCustomer
};

Use as:

customerCreator.createCustomer()
    .done(function (model) {
        // yay! let's use this model
    })
    .fail(function () {
        console.error("Cannot create customer");
    });

You should also move the .fail() handling outside, as high up in the application as possible, so that the wording in your error message can have a more accurate context.

P.S. As a nitpick, shouldn't you be using a POST request instead of a GET to create an entity?