Counter with hooks example.

Counter.js

export const Counter: SFC<RouteComponentProps> = () => {
  const [count, setCount] = useState(0);
  useEffect(() => {
    console.log('count', count);
  })
  return (
    <View>
      <h3>Counter</h3>
      <p>Counter: {count}</p>
      <div>
        <button onClick={useCallback(() => {
          setCount(count + 1)
          console.log("count internal", count);
          }, [count])}
          >
          Add
        </button>
        <button onClick={useCallback(() => setCount(count - 1), [count])}>Subtract</button>
      </div>
    </View>
  );
};