File upload in sharepoint list after the items created using jquery

Hi
I tried to add item in sharepoint list and then using the id tried to upload. The problem here is when i do debug the attachment is added to the item. If i run normally attachment has not added.

      createTask = function () {

            var x = $scope.task;

            var call = addItemFields(x);
            call.done(function (data, textStatus, jqXHR) {
                var item = data.d;


                function uploadDocument() {
                var element = document.getElementById("inputFile");
                var file = element.files[0];
                var parts = element.value.split("\\");
               var fileName = parts[parts.length - 1];

               var reader = new FileReader();
                reader.onload = function (e) {
                    addItem(e.target.result, fileName, item);
                }
                reader.onerror = function (e) {
                    alert(e.target.error);
                }
               reader.readAsArrayBuffer(file);

               function addItem(buffer, fileName, item) {
                   var call2 = uploadDocument(buffer, fileName, item);
                   call2.done(function (data, textStatus, jqXHR) {
                       alert("successfully uploaded");
                   });
                  call2.fail(function (jqXHR, textStatus, errorThrown) {
                    failHandler(jqXHR, textStatus, errorThrown);
                });

            }


            });
            call.fail(function (jqXHR, textStatus, errorThrown) {
                failHandler(jqXHR, textStatus, errorThrown);
            });

        }

        function uploadDocument(buffer, fileName, item) {

            var url = _spPageContextInfo.webAbsoluteUrl + "/_api/web/lists/GetByTitle('MeetingTasks')/items(" + item.Id + ")/AttachmentFiles/add(FileName='" + fileName + "')";
            var call = jQuery.ajax({
                url: url,
                type: "POST",
                data: buffer,
                processData: false,
                headers: {
                    Accept: "application/json;odata=verbose",
                    "X-RequestDigest": jQuery("#__REQUESTDIGEST").val(),
                    "Content-Length": buffer.byteLength,
                    "IF-MATCH": item.__metadata.etag,
                    "X-Http-Method": "MERGE"
                }
            });

            return call;

        }

        function failHandler(jqXHR, textStatus, errorThrown) {
            var response = JSON.parse(jqXHR.responseText);
            var message = response ? response.error.message.value : textStatus;
            alert("Call failed. Error: " + message);
        }

        function addItemFields(item) {
            var now = new Date();
            var call = jQuery.ajax({
                url: _spPageContextInfo.webAbsoluteUrl +
                    "/_api/Web/Lists/getByTitle('MeetingTasks')/Items",
                type: "POST",
                data: JSON.stringify({
                    "__metadata": { type: "SP.Data.MeetingTasksListItem" },
                    Title: item.taskName,
                    Body: item.description, DueDate: item.dueDate
                }),
                headers: {
                    Accept: "application/json;odata=verbose",
                    "Content-Type": "application/json;odata=verbose",
                    "X-RequestDigest": jQuery("#__REQUESTDIGEST").val()
                }
            });

            return call;
        }

    });

regards
jhanani