Sending ajax get request to node, response is undefined

I have a node server running a single web page. The page has a contact form with a send button.

If I click send, the following code runs:

$('.contactsend').click(function(){
    $.ajax({
        method: "GET",
        url: "http://127.0.0.1:3000/contact",
        dataType: "jsonp"
    })  .done(function(data) {
            alert( data );
        })
        .fail(function() {
            alert( "error" );
        })
        .always(function() {
            alert( "complete" );
        });
})

Seems ok so far, reached the page.

This is what the middleware does:

router.get('/', function(req, res, next) {
  res.send({test:'test'})
  //res.send('test')
});

After sending this message, the web page displays the following message:

Uncaught SyntaxError: Unexpected token :

If I don't send , jsonbut a string, the message is like

Uncaught ReferenceError: test is not defined