30秒学会 React 片段 – React useGetSet hook

Creates a stateful value, returning a getter and a setter function.

• Use the useRef() hook to create a ref that holds the stateful value, initializing it with initialState.
• Use the useReducer() hook that creates a new object every time it’s updated and return its dispatch.
• Use the useMemo() hook to memoize a pair of functions. The first one will return the current value of the state ref and the second one will update it and force a re-render.

代码实现

const useGetSet = initialState => {
  const state = React.useRef(initialState);
  const [, update] = React.useReducer(() => ({}));

  return React.useMemo(
    () => [
      () => state.current,
      newState => {
        state.current = newState;
        update();
      },
    ],
    []
  );
};

使用样例

const Counter = () => {
  const [getCount, setCount] = useGetSet(0);
  const onClick = () => {
    setTimeout(() => {
      setCount(getCount() + 1);
    }, 1_000);
  };

  return <button onClick={onClick}>Count: {getCount()}</button>;
};

ReactDOM.createRoot(document.getElementById('root')).render(
  <Counter />
);

翻译自：https://www.30secondsofcode.org/react/s/use-get-set