Question

我发现我正在整个应用程序中重用行为，当用户在某个元素之外单击时，我可以将其隐藏。

通过引入钩子，我可以将其放在钩子中并在各个组件之间共享，以免我在每个组件中编写相同的逻辑吗？

我已经在以下组件中实现了一次。

const Dropdown = () => {
    const [isDropdownVisible, setIsDropdownVisible] = useState(false);   
    const wrapperRef = useRef<HTMLDivElement>(null);

    const handleHideDropdown = (event: KeyboardEvent) => {
        if (event.key === 'Escape') {
            setIsDropdownVisible(false);
        }
    };

    const handleClickOutside = (event: Event) => {
        if (
            wrapperRef.current &&
            !wrapperRef.current.contains(event.target as Node)
        ) {
            setIsDropdownVisible(false);
        }
    };

    useEffect(() => {
        document.addEventListener('keydown', handleHideDropdown, true);
        document.addEventListener('click', handleClickOutside, true);
        return () => {
            document.removeEventListener('keydown', handleHideDropdown, true);
            document.removeEventListener('click', handleClickOutside, true);
        };
    });

    return(
       <DropdownWrapper ref={wrapperRef}>
         <p>Dropdown</p>
       </DropdownWrapper>
    );
}

Answer 1

这是可能的。

您可以创建一个名为useComponentVisible的可重用钩子

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

export default function useComponentVisible(initialIsVisible) {
    const [isComponentVisible, setIsComponentVisible] = useState(initialIsVisible);
    const ref = useRef<HTMLDivElement>(null);

    const handleHideDropdown = (event: KeyboardEvent) => {
        if (event.key === 'Escape') {
            setIsElementVisible(false);
        }
    };

    const handleClickOutside = (event: Event) => {
        if (ref.current && !ref.current.contains(event.target as Node)) {
            setIsElementVisible(false);
        }
    };

    useEffect(() => {
        document.addEventListener('keydown', handleHideDropdown, true);
        document.addEventListener('click', handleClickOutside, true);
        return () => {
            document.removeEventListener('keydown', handleHideDropdown, true);
            document.removeEventListener('click', handleClickOutside, true);
        };
    });

    return { ref, isComponentVisible, setIsComponentVisible };
}

然后在要添加功能的组件中执行以下操作：

const DropDown = () => {

    const { ref, isComponentVisible } = useComponentVisible(true);

    return (
       <div ref={ref}>
          {isComponentVisible && (<p>Going into Hiding</p>)}
       </div>
    );

}

在此处找到一个codesandbox示例。

Answer 2

好吧，在苦苦挣扎了一点之后，我来到了下一个工作坊，除了保罗·菲茨杰拉德所做的那样，而且我的回答也包括了转变

首先，我希望我的下拉菜单在ESCAPE键事件和鼠标外部单击时关闭。为了避免为每个事件创建一个useEffect，我以一个辅助函数结尾：

//useDocumentEvent.js

import { useEffect } from 'react'
export const useDocumentEvent = (events) => {
  useEffect(
    () => {
      events.forEach((event) => {
        document.addEventListener(event.type, event.callback)
      })
      return () =>
        events.forEach((event) => {
          document.removeEventListener(event.type, event.callback)
        })
    },
    [events]
  )
}

然后，使用useDropdown挂钩带来所有所需的功能：

//useDropdown.js

import { useCallback, useState, useRef } from 'react'
import { useDocumentEvent } from './useDocumentEvent'

/**
 * Functions which performs a click outside event listener
 * @param {*} initialState initialState of the dropdown
 * @param {*} onAfterClose some extra function call to do after closing dropdown
 */
export const useDropdown = (initialState = false, onAfterClose = null) => {
  const ref = useRef(null)
  const [isOpen, setIsOpen] = useState(initialState)

  const handleClickOutside = useCallback(
    (event) => {
      if (ref.current && ref.current.contains(event.target)) {
        return
      }
      setIsOpen(false)
      onAfterClose && onAfterClose()
    },
    [ref, onAfterClose]
  )

  const handleHideDropdown = useCallback(
    (event) => {
      if (event.key === 'Escape') {
        setIsOpen(false)
        onAfterClose && onAfterClose()
      }
    },
    [onAfterClose]
  )

  useDocumentEvent([
    { type: 'click', callback: handleClickOutside },
    { type: 'keydown', callback: handleHideDropdown },
  ])

  return [ref, isOpen, setIsOpen]
}

最后，要使用此功能（它具有一些情感样式）：

//Dropdown.js
import React, { useState, useEffect } from 'react'
import styled from '@emotion/styled'

import { COLOR } from 'constants/styles'
import { useDropdown } from 'hooks/useDropdown'
import { Button } from 'components/Button'

const Dropdown = ({ children, closeText, openText, ...rest }) => {
  const [dropdownRef, isOpen, setIsOpen] = useDropdown()
  const [inner, setInner] = useState(false)
  const [disabled, setDisabled] = useState(false)
  const timeout = 150
  useEffect(() => {
    if (isOpen) {
      setInner(true)
    } else {
      setDisabled(true)
      setTimeout(() => {
        setDisabled(false)
        setInner(false)
      }, timeout + 10)
    }
  }, [isOpen])
  return (
    <div style={{ position: 'relative' }} ref={dropdownRef}>
      <Button onClick={() => setIsOpen(!isOpen)} disabled={disabled}>
        {isOpen ? closeText || 'Close' : openText || 'Open'}
      </Button>
      <DropdownContainer timeout={timeout} isVisible={isOpen} {...rest}>
        {inner && children}
      </DropdownContainer>
    </div>
  )
}

const DropdownContainer = styled.div(
  {
    position: 'absolute',
    backgroundColor: COLOR.light,
    color: COLOR.dark,
    borderRadius: '2px',
    width: 400,
    boxShadow: '0px 0px 2px 0px rgba(0,0,0,0.5)',
    zIndex: 1,
    overflow: 'hidden',
    right: 0,
  },
  (props) => ({
    transition: props.isVisible
      ? `all 700ms ease-in-out`
      : `all ${props.timeout}ms ease-in-out`,
    maxHeight: props.isVisible ? props.maxHeight || 300 : 0,
  })
)

export { Dropdown }

要使用它，只需：

//.... your code
<Dropdown>
  <Whatever.Needs.To.Be.Rendered />
</Dropdown>
//... more code

此解决方案的信用额为previous answer，此处为this entry，中为article。

使用钩子检测React组件外部的点击

2 个答案: