InputNumber with spinner mode throws a JS exception

[RealNumberX]

I'm submitting a ... (check one with "x")

[x] bug report 
[ ] feature request 
[ ] support request

Current behavior
TypeError gets thrown when text-field of input-number component is empty and the value is about to be incremented or decremented via buttons.

Expected behavior
TypeError does not get thrown. New value of the field should be 0 +/- [step] if no minimum or maximum boundaries are set.

Minimal reproduction of the problem with instructions

• Go To PrimeNG Documentation InputSpinner Component
• In the example with buttons delete the value of the input field
• open Dev-Tools in browser
• try to increment or decrement the value

[mertsincan]

Hi,

Thanks a lot for the PR! However, it had some conflict problems. I guess this was about my previous commits. Sorry for noticing your PR late.

Thanks again for your PR,
Best Regards,