在react开发中经常会经常会碰到这种警告:Warning: Can't perform a React state update on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions and asynchronous tasks in a useEffect cleanup function.

原因呢谁都知道在已卸载的组件上执行setState，解决方案有很多,在卸载的时候对所有的操作进行清除、增加一个标记页面卸载的时候重置这个标记等等。

这些解决方案都能解决这个问题，但对于我来说不是最好的解决方案，或者说不是我想要的解决方案，分享一个我的解决方案，拥抱hooks

import { Dispatch, SetStateAction, useCallback, useEffect, useRef, useState } from 'react';

/**
 * useUnmounted
 * @returns boolean
 * whether the component is unmounted
 */
export function useUnmounted() {
  const unmountedRef = useRef(false);
  useEffect(() => {
    return () => {
      unmountedRef.current = true;
    };
  }, []);
  return unmountedRef.current;
}
/**
 * @method useAsyncState
 * Prevent React state update on an unmounted component.
 */
export function useAsyncState<S>(initialState?: S | (() => S)): [S | undefined, Dispatch<SetStateAction<S>>] {
  const unmountedRef = useUnmounted();
  const [state, setState] = useState(initialState);
  const setAsyncState = useCallback((s) => {
    if (unmountedRef) return;
    setState(s);
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);
  return [state, setAsyncState];
}

使用也很方便

  const [state, setState] = useState('test');
  //替换为
  const [state, setState] = useAsyncState('test');

原理我在这就不多做赘述了，就是一个思路的问题

更新于2021-12-30