I have a React stateless component using redux and hooks. I need to display the number of items on page load (useEffect) and update it every time I add or remove an item (store.subscribe)

```
useEffect(() => {
    setState({
        items: store.getState().items.length
    });
}, []);

store.subscribe(() => {
    setState({
        items: store.getState().items.length
    });
});

```

but this is causing the console to display the 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 and asynchronous tasks in a useEffect cleanup function.**
.

How can I unsubscribe from inside useEffect?