tcomb-validation | Validation library based on type combinators | Validation library

Using the tcomb-form-native library with react native - I've set the keyboardType to email-address. How do I add a regex or email validator to the form? Do I have to do it on the submit function (and throw a special error?) or is there a regex validation field I can set using the library?

I noticed that the tcomb-validation https://github.com/gcanti/tcomb-validationlibrary has a RegExp type field - but I don't see any examples of how to use it. The example shown seems to test if a field is a regex pattern, which is a confusing use case, because you would normally want to test a field against a regex pattern, not enter a regex pattern into a field.