我有一个需要有条件地将孩子插入模态的例子。像这样，贝娄。

const [view, setView] = useState(VIEWS.SomeView)

return (
    <Modal onClose={onClose}>
      {VIEWS.Result === view ? (
        <Result onDeny={() => setView(VIEWS.Details)} />
      ) : VIEWS.Details === view ? (
        <Details onDeny={() => setView(VIEWS.Result) /> />
      ) : null}
    </Modal>
  )

所以parent.contains（event.target）在这里不起作用，因为一旦分离了子级，parent（modal）就不再包含event.targe。

我的解决方案（到目前为止有效，没有任何问题）是这样写：

const listener = (event: MouseEvent) => {
   if (parentNodeRef && !event.path.includes(parentNodeRef)) callback()
}

若父级包含已经分离的树中的元素，那个么它不会触发回调。

编辑：event.path是新的，尚未在所有浏览器中退出。请改用composedPath。

这是我解决问题的方法

我从我的自定义钩子返回一个布尔值，当这个值发生变化时（如果单击在我作为参数传递的ref之外，则为true），这样我就可以用useEffect钩子捕捉到这个变化，我希望你能清楚。

下面是一个活生生的例子：codesandbox上的实时示例

import { useEffect, useRef, useState } from "react";

const useOutsideClick = (ref) => {
  const [outsieClick, setOutsideClick] = useState(null);

  useEffect(() => {
    const handleClickOutside = (e) => {
      if (!ref.current.contains(e.target)) {
        setOutsideClick(true);
      } else {
        setOutsideClick(false);
      }

      setOutsideClick(null);
    };

    document.addEventListener("mousedown", handleClickOutside);

    return () => {
      document.removeEventListener("mousedown", handleClickOutside);
    };
  }, [ref]);

  return outsieClick;
};

export const App = () => {
  const buttonRef = useRef(null);
  const buttonClickedOutside = useOutsideClick(buttonRef);

  useEffect(() => {
    // if the the click was outside of the button
    // do whatever you want
    if (buttonClickedOutside) {
      alert("hey you clicked outside of the button");
    }
  }, [buttonClickedOutside]);

  return (
    <div className="App">
      <button ref={buttonRef}>click outside me</button>
    </div>
  );
}

Ez的方式。。。（2022年更新）

创建挂钩：useOutsideClick.ts

export function useOutsideClick(ref: any, onClickOut: () => void){
    useEffect(() => {
        const onClick = ({target}: any) => !ref.contains(target) && onClickOut?.()
        document.addEventListener("click", onClick);
        return () => document.removeEventListener("click", onClick);
    }, []);
}

将componentRef添加到组件并调用useOutsideClick

export function Example(){

  const componentRef = useRef();

  useOutsideClick(componentRef.current!, () => {
   // do something here
  });

  return ( 
    <div ref={componentRef as any}> My Component </div>
  )
}

componentWillMount(){

  document.addEventListener('mousedown', this.handleClickOutside)
}

handleClickOutside(event) {

  if(event.path[0].id !== 'your-button'){
     this.setState({showWhatever: false})
  }
}

事件路径[0]是最后单击的项目

在我的DROPDOWN案例中，Ben Bud的解决方案工作得很好，但我有一个单独的切换按钮和一个onClick处理程序。因此，外部单击逻辑与单击切换按钮冲突。下面是我如何通过传递按钮的ref来解决这个问题：

import React, { useRef, useEffect, useState } from "react";

/**
 * Hook that triggers onClose when clicked outside of ref and buttonRef elements
 */
function useOutsideClicker(ref, buttonRef, onOutsideClick) {
  useEffect(() => {

    function handleClickOutside(event) {
      /* clicked on the element itself */
      if (ref.current && !ref.current.contains(event.target)) {
        return;
      }

      /* clicked on the toggle button */
      if (buttonRef.current && !buttonRef.current.contains(event.target)) {
        return;
      }

      /* If it's something else, trigger onClose */
      onOutsideClick();
    }

    // Bind the event listener
    document.addEventListener("mousedown", handleClickOutside);
    return () => {
      // Unbind the event listener on clean up
      document.removeEventListener("mousedown", handleClickOutside);
    };
  }, [ref]);
}

/**
 * Component that alerts if you click outside of it
 */
export default function DropdownMenu(props) {
  const wrapperRef = useRef(null);
  const buttonRef = useRef(null);
  const [dropdownVisible, setDropdownVisible] = useState(false);

  useOutsideClicker(wrapperRef, buttonRef, closeDropdown);

  const toggleDropdown = () => setDropdownVisible(visible => !visible);

  const closeDropdown = () => setDropdownVisible(false);

  return (
    <div>
      <button onClick={toggleDropdown} ref={buttonRef}>Dropdown Toggler</button>
      {dropdownVisible && <div ref={wrapperRef}>{props.children}</div>}
    </div>
  );
}

因为对我来说！ref.current.contains（e.target）无法工作，因为ref中包含的DOM元素正在更改，我提出了一个稍微不同的解决方案：

function useClickOutside<T extends HTMLElement>(
  element: T | null,
  onClickOutside: () => void,
) {
  useEffect(() => {
    function handleClickOutside(event: MouseEvent) {
      const xCoord = event.clientX;
      const yCoord = event.clientY;

      if (element) {
        const { right, x, bottom, y } = element.getBoundingClientRect();
        if (xCoord < right && xCoord > x && yCoord < bottom && yCoord > y) {
          return;
        }

        onClickOutside();
      }
    }

    document.addEventListener('click', handleClickOutside);
    return () => {
      document.removeEventListener('click', handleClickOutside);
    };
  }, [element, onClickOutside]);