30秒学会 React 片段 – React useOnGlobalEvent hook

Executes a callback whenever an event occurs on the global object.

• Use the useRef() hook to create a variable, listener, which will hold the listener reference.
• Use the useRef() hook to create a variable that will hold the previous values of the type and options arguments.
• Use the useEffect() hook and EventTarget.addEventListener() to listen to the given event type on the Window global object.
• Use EventTarget.removeEventListener() to remove any existing listeners and clean up when the component unmounts.

代码实现

const useOnGlobalEvent = (type, callback, options) => {
  const listener = React.useRef(null);
  const previousProps = React.useRef({ type, options });

  React.useEffect(() => {
    const { type: previousType, options: previousOptions } = previousProps;

    if (listener.current) {
      window.removeEventListener(
        previousType,
        listener.current,
        previousOptions
      );
    }

    listener.current = window.addEventListener(type, callback, options);
    previousProps.current = { type, options };

    return () => {
      window.removeEventListener(type, listener.current, options);
    };
  }, [callback, type, options]);
};

使用样例

const App = () => {
  useOnGlobalEvent('mousemove', e => {
    console.log(`(${e.x}, ${e.y})`);
  });

  return <p>Move your mouse around</p>;
};

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

翻译自：https://www.30secondsofcode.org/react/s/use-on-global-event