group_by : [group_by]; //check each group by parameter for (var i = 0, len = group_by.length; i < len; i++) { if ($parse(group_by[i])(prev_item) !== … We will make use of FileSelectDirective and FileDropDirective from ng2-file-upload to achieve this example. 2. Angular offers SelectMultipleControlValueAccessor directive for selecting multiple options in select dropdown. To change the groups order in grouping panel, left-click on the group and drag-drop it over some other group. Let's say that our application pulls data from that API for a form that we need to edit.