Calendar widget provides such an option, where you can select whether to show the widget when there are no events or not.
Setting the widget’s visibility
Open the widget’s settings and go to Content > Widget Visibility block. Here you need to select the appropriate option from the dropdown in the Hide widget if field. If you want to show the widget permanently, choose the Always show option. In case it is necessary to hide it when the posts query is empty you need to choose the Query is empty option.
That’s it. Use this simple way set the Calendar widget’s visibility of JetEngine plugin.