How to avoid repeating code in if/else statement inside AJAX

Question

I'm trying to do if/else inside Ajax , but as you can see in my script I'm repeating my code and i think it is better way do archive this in one line or doing if/else before Ajax and to be honest i don't know how exactly should i do Can anyone please help me or point me in the right direction!
Thanks in advance :)

function RMAfunction() {
        var model = {
            Serienummer: $("#notavailable").val(),
            SelectedSerieText: $("#ddlSerial option:selected").text(),
            Kundenavn: $("#Kundenavn").val(),
            Ordrenummer: $("#Ordrenummer").val()
            }
            if (model.Serienummer === 'not available') {
                $.ajax({
                    type: 'POST',
                    url: '@Url.Action("ProcessRequestRMA", "Account")',
                    dataType: 'json',
                    data: {
                        Serienummer: model.Serienummer,
                        Kundenavn: model.Kundenavn,
                        Ordrenummer: model.Ordrenummer,
                    },
                    success: function (status) {
                        if (status) {

                            status.Serienummer = model.Serienummer;
                            status.Kundenavn = model.Kundenavn;
                            status.Ordrenummer = model.Ordrenummer;
                        }
                        else {
                            alert("Something Wrong");
                        }
                    },
                    error: function () {
                        console.log('something went wrong - debug it!');
                    }
                });
            }
            else {
                    $.ajax({
                    type: 'POST',
                    url: '@Url.Action("ProcessRequestRMA", "Account")',
                    dataType: 'json',
                    data: {
                        Serienummer: model.SelectedSerieText,
                        Kundenavn: model.Kundenavn,
                        Ordrenummer: model.Ordrenummer
                    },
                    success: function (status) {
                        if (status) {
                            status.Serienummer = model.SelectedSerieText;
                            status.Kundenavn = model.Kundenavn;
                            status.Ordrenummer = model.Ordrenummer;     
                        }
                        else {
                            alert("Something Wrong");
                        }
                    },
                    error: function () {
                        console.log('something went wrong - debug it!');
                    }
                });

            }
}

Answer 1

The only change is whether you use the Serienummer or SelectedSerieText in the properties of model based on the original value of Serienummer. As such, you can just use a ternary expression where that value is used. Try this:

function RMAfunction() {
  var model = {
    Serienummer: $("#notavailable").val(),
    SelectedSerieText: $("#ddlSerial option:selected").text(),
    Kundenavn: $("#Kundenavn").val(),
    Ordrenummer: $("#Ordrenummer").val()
  }
  var hasSerieNummer = model.Serienummer === 'not available';

  $.ajax({
    type: 'POST',
    url: '@Url.Action("ProcessRequestRMA", "Account")',
    dataType: 'json',
    data: {
      Serienummer: hasSerieNummer ? model.Serienummer : model.SelectedSerieText,
      Kundenavn: model.Kundenavn,
      Ordrenummer: model.Ordrenummer,
    },
    success: function(status) {
      if (status) {
        status.Serienummer = hasSerieNummer ? model.Serienummer : model.SelectedSerieText;
        status.Kundenavn = model.Kundenavn;
        status.Ordrenummer = model.Ordrenummer;
      } else {
        alert("Something Wrong");
      }
    },
    error: function() {
      console.log('something went wrong - debug it!');
    }
  });
}

This could potentially be further reduced by using a function in the model object to contain the logic which determines which identifier to return:

function RMAfunction() {
  var model = {
    Serienummer: $("#notavailable").val(),
    SelectedSerieText: $("#ddlSerial option:selected").text(),
    Kundenavn: $("#Kundenavn").val(),
    Ordrenummer: $("#Ordrenummer").val(),
    GetIdentifier: function() {
      return this.Serienummer === 'not available' ? this.Serienummer : this.SelectedSerieText;
    }
  }

  $.ajax({
    type: 'POST',
    url: '@Url.Action("ProcessRequestRMA", "Account")',
    dataType: 'json',
    data: {
      Serienummer: model.GetIdentifier(), // usage here
      Kundenavn: model.Kundenavn,
      Ordrenummer: model.Ordrenummer,
    },
    success: function(status) {
      if (status) {
        status.Serienummer = model.GetIdentifier(); // and here
        status.Kundenavn = model.Kundenavn;
        status.Ordrenummer = model.Ordrenummer;
      } else {
        alert("Something Wrong");
      }
    },
    error: function() {
      console.log('something went wrong - debug it!');
    }
  });
}

Answer 2

Try this also correct,

var model = {
        Serienummer: $("#notavailable").val(),
        SelectedSerieText: $("#ddlSerial option:selected").text(),
        Kundenavn: $("#Kundenavn").val(),
        Ordrenummer: $("#Ordrenummer").val()
        }
        if (model.Serienummer === 'not available') {
            var data = {
                    Serienummer: model.Serienummer,
                    Kundenavn: model.Kundenavn,
                    Ordrenummer: model.Ordrenummer,
                };
        }else{
            var data = {
                Serienummer: model.SelectedSerieText,
                    Kundenavn: model.Kundenavn,
                    Ordrenummer: model.Ordrenummer
            };
        }
            $.ajax({
                type: 'POST',
                url: '@Url.Action("ProcessRequestRMA", "Account")',
                dataType: 'json',
                data: JSON.stringify(data);
                success: function (status) {
                    if (status) {
                        if (model.Serienummer === 'not available') {
                            status.Serienummer = model.Serienummer;
                        }else{
                            status.Serienummer = model.SelectedSerieText;
                        }
                            status.Kundenavn = model.Kundenavn;
                            status.Ordrenummer = model.Ordrenummer;
                    }
                    else {
                        alert("Something Wrong");
                    }
                },
                error: function () {
                    console.log('something went wrong - debug it!');
                }
            });