【flowtype/React/Class】これ。how to fix 「Covariant property `[fn]` incompatible with contravariant use in ``` assignment of property `[fn]`」
flowtypeをReactに取り入れて、class構文で使おうとするとこのようなエラーが出る。
If you incorporate flowtype into React and try to use it in class syntax, you get such an error.
fix to
Flowtype in class syntax
flowtype playground
https://github.com/kenmori/flow