appWithUseCallback.js

export default ()=>{
	const [childState, setChildState] = useState(0);
	//using useCallback
	const awesomeChildListRenderItem = useCallback(
	    ({ item }) => (
		      <AwesomeChild {...item} onPress={(number)=>{setChildState(number)}} />
	    ),[]);
    const awesomeChildListKeyExtractor = useCallback( (item) => `awesome-child-key-${item.id}`,[]);
	return(
	    <FlatList
		    renderItem={awesomeChildListRenderItem}
		    keyExtractor={awesomeChildListKeyExtractor}
	    />
    )
}