Strange error (undefined is not a function)

Expo Development Tools
1

What does it mean? How can I fix it?

Screenshot (9)
Screenshot (9)1277×664 34.7 KB

2

This.input doesn’t have a charCodeAt property

3

This.input is not used. Real errors I fixed without Snack (CRNA + Expo = normal error logging). Errors were in imports and because I used .map() instead of ListView.