Open Radar

 
The timer class in WatchKit provides basic support for a few pre-defined date formats, and for which possible calendar components (days, hours, minutes, seconds, etc.) the timer will show. This is actually a pretty nice form of customization, but it's not quite deep enough. Some timers may wish to show hours or minutes even when their contents are zero, or format the text in different ways.

This level of customization is actually available in the WKInterfaceTimer's sister class, WKInterfaceDate, which takes a customizable date format string as a parameter. My proposal is that the WKInterfaceTimer should take an optional date format string as a parameter as well. If a date format string is present, it should use that format for displaying the timer. If the format string isn't present, then use the default customization parameters.