react-native-form-helpers

Step 1:
npm install react-native-form-helpers

Step 2:
Create a dictionary file (example dictionary)

Step 3:

import RNFormHelpers from "./react-native-form-helpers";
import { validationDictionary } from "./dictionary.js"; // location of your dictionary file

export const validationService = RNFormHelpers({
  dictionary: validationDictionary
});

Step 4:
Import into your form and utilize the built-in methods. See below tutorial or sample app for more details.

Tutorial Series:

https://medium.com/lawnstarter-engineering/how-to-create-custom-forms-with-validation-and-scroll-to-invalid-logic-in-react-native-part-one-43e5f7cdf807

https://medium.com/lawnstarter-engineering/how-to-create-custom-forms-with-validation-and-scroll-to-invalid-logic-in-react-native-part-two-9834849d4d78

https://medium.com/lawnstarter-engineering/how-to-create-custom-forms-with-validation-and-scroll-to-invalid-logic-in-react-native-f6a4cc049095