Dojo dijit
The widget is a dojo dijit, which derives from the BaseWidget dijit; therefore, you can use the existing dijit as normal. With performance considerations, don’t mix in the _WidgetsInTemplateMixin in the BaseWidget. If you need to use dijit in the widget’s UI template file, mix in this class and require all of the dijits that you use in the template file. For more information, see Creating template-based widgets.