warning: Can't perform a React state update on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions code example

Example: react warning can't perform a react state update on an unmounted component

componentWillUnmount() {
    // fix Warning: Can't perform a React state update on an unmounted component
    this.setState = (state,callback)=>{
        return;
    };
}