How do I prevent a user from inputting multiple periods in React Native?

I'm using UI Kitten's Input component and react-hook-form and I don't want the user to put more than one period onPress so once one period is inputted, the user wouldn't be allowed to input another; this is for decimal points.

Example:

Allowed Input -> .9, 0.9Disallowed Input -> ..9, ..09

Any help would be appreciated, thank you!