selector 선언과 사용

selector 선언

const charCountState = selector({
  key: 'charCountState', // unique ID (with respect to other atoms/selectors)
  get: ({get}) => {
    const text = get(textState);

    return text.length;
  },
});

selector 사용

function CharacterCount() {
  const count = useRecoilValue(charCountState);

  return <>Character Count: {count}</>;
}