Hi is there anything like cell.addClass('cssClass')? I want to add one or more classes to cell but all I found is args.cell.cssClass = "cssClass", so if I want to add another class I have to check if cssClass is not empty in order to add a trailing space or not.
You can use DayPilot.Util.addClassToString() helper method:
args.cell.cssClass = DayPilot.Util.addClassToString(args.cell.cssClass, "my-class");
This will handle the spaces and also check if "my-class" is already added.