import { useEffect, useMemo, useState } from "octane";
props { initialCount, step, onCountChange }: { initialCount: number; step: number; onCountChange: (count: number) => void }
setup const [count, setCount] = useState(initialCount);
setup const doubled = useMemo(() => count * 2);
setup useEffect(() => onCountChange(count));

section.counter(aria-live="polite")
  h2 Hook counter
  p Current: #{count}
  p Doubled: #{doubled}
  .actions
    button(type="button" onClick={() => setCount(count - step)}) Decrease
    button(type="button" onClick={() => setCount(count + step)}) Increase