🐛 No timepicker is shown if startDate is NULL or undefined.

[cmjoseph07]

Describe the bug
If I have a datepicker component like the example REPL, if I change startDate = new Date() to startDate = NULL and click on the input field, no timepicker is shown. However, I have an action onDayClick so I have to click the input field twice if I want to set something with no initial date.

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Use the timepicker example
3. Change the startDate to an undefined or NULL value
4. See that timepicker no longer appears

Expected behavior
Expect timepicker to still be there so I can pick time than pick date which has an action on it.

Or could you advise me how to clear formattedStartDate if nothing is selected?