MAGETWO-80198: [2.2.x] - Fix issue #10565 #10575

Author: omiroshnichenko

app/code/Magento/Ui/view/base/web/js/form/element/multiselect.js

@@ -52,7 +52,7 @@ define([
          * @param {Array} data - current component value
          */
         setPrepareToSendData: function (data) {
-            if (!data.length) {
+            if (_.isUndefined(data) || !data.length) {
                 data = '';
             }
 

dev/tests/js/jasmine/tests/app/code/Magento/Ui/base/js/form/element/multiselect.test.js

@@ -52,6 +52,11 @@ define([
                 expect(obj.source.set).toHaveBeenCalledWith(dataScope + '-prepared-for-send', '');
             });
 
+            it('Check method call with undefined as parameter.', function () {
+                expect(obj.setPrepareToSendData(undefined)).toBeUndefined();
+                expect(obj.source.set).toHaveBeenCalledWith(dataScope + '-prepared-for-send', '');
+            });
+
             it('Check method call with array with data as parameter.', function () {
                 expect(obj.setPrepareToSendData(['1', '2', '3'])).toBeUndefined();
                 expect(obj.source.set).toHaveBeenCalledWith(dataScope + '-prepared-for-send', ['1', '2', '3']);