class Game extends Component { constructor() { super() this.state = { speed: 0 } //firebaseInit() } render() { return (
In my case, I got the error on the setState line:
increment(){ this.setState(state => { count: state.count + 1 }); }
I changed it to this, now it works
increment(){ this.setState(state => { const count = state.count + 1 return { count }; }); }