У вашего броузера проблема в совместимости с HTML5
Code on Github - https://github.com/MyNameIsURL/redux-simple-counter
Learn React and Redux in this React Redux Tutorial Basics How To by building a simple counter app in this tutorial. I start with create-react-app to bootstrap the project and then walk through the React Redux process, showing how the state of your app is maintained and how actions are dispatched through your React Redux application in this React Redux Tutorial Basics How To. Checkout the final project code on Github in the link above.