title: Sending request with angular - empty elements in request
body: <p>I'm sending POST request with angular with submitted form.
  I have optionals input fields and when I type something there and delete it then in my request I have this field containing "".
  Is that how it should be?</p>
  
  <p>Thats how my form look:</p>
  
  <pre><code>&lt;label class="col-md-2 col-xs-2 my-label"  for="contactFirstName"&gt;Imię&lt;/label&gt;
        &lt;div class="col-md-3 col-xs-3"&gt;
          &lt;input type="text" class="form-control" id="contactFirstName" name="contactFirstName"
                 placeholder="Imię"
                 ng-model="loan.newLoan.contactPerson.firstName" &gt;
        &lt;/div&gt;
  </code></pre>
  
  <p>And thats how I'm sending the request:</p>
  
  <pre><code>function create() {
  return RequestFactory.save({id1:'loans', id2:'create'},vm.newLoan,
      function () {
        MessageFactory.setSuccess({show:true, msg:'success'});
        $state.reload('loan.new');
      }, function(response){
        vm.isError = true;
        ErrorFactory.errorHandler(vm.errorMessages, response);
      });
  }
  </code></pre>
  
  <p>And when sending, in my request json with this field looks like this:</p>
  
  <pre><code> {"firstName":""}
  </code></pre>
  
  <p>Is that ok? Or there should't be this field in the request if its empty?
  What should I do with this?</p>