The initial writing for "useAsyncExtendedState" said "Don't use extendState for everything! Use it only when you know you need to merge a partial state.". However, the example doesn't use "setState" at all. This feels like a gap or tension in the API design—if setState doesn't get used in practice, why force users to include it? Instead, I think the default react setState pattern is much better, since it allows you to easily set *or* extend your state depending on your usecase:

    const [state, setState] = useState({});
    
    // replace
    setState({foo: 1, bar: 2});
    
    // extend
    setState(currentState => ({...currentState, foo: 1}));