react hooks 计数器实现代码

  const [count, setCount] = useState(0)
  setCount(180)
  useEffect(() => {
    clearTimeout(timer)
    timer = setTimeout(() => {
      if (count > 1) {
        setCount(count - 1)
      } else {
        setIsSendEmail(false)
      }
    }, 1000)
    // eslint-disable-next-line
  }, [count])

import { useState, useRef, useEffect } from 'react'
import Api from '../../../api'
import Toast from 'react-native-root-toast'
import { checkEmail } from '../../../utils/tools'
import AsyncStorage from '@react-native-async-storage/async-storage'
let timer
export default function useList(props) {
  const [username, setUsername] = useState(
    ''
  )
  const [emailCode, setEmailCode] = useState(
   ''
  )
  const [isSendEmail, setIsSendEmail] = useState(false)
  const [count, setCount] = useState(0)
  const [emailId, setEmailId] = useState('')
  const [avatar, setAvatar] = useState(null)
  const [nickname, setNickname] = useState(
    ''
  )
  const [password, setPassword] = useState(
    ''
  )
  const [code, setCode] = useState(
    ''
  )
  const [visible, setVisible] = useState(false)
  // eslint-disable-next-line
  const [isLoading, setIsLoading] = useState(false)
  const [captchaId, setCaptchaId] = useState('')
  const [captcha, setCaptcha] = useState('')
  const [visible1, setVisible1] = useState(false)
  const usernameEl = useRef(null)
  const { navigation } = props
  const toggleDialog1 = () => {
    setVisible1(!visible1)
  }
  const handleInput = (e) => {
    setUsername(e)
  }
  const handleSendEmail = () => {
    const { isEmail, message } = checkEmail(username)
    if (username.trim() === '') {
      Toast.show('邮箱不能为空', {
        duration: 3000,
        position: Toast.positions.CENTER,
      })
      return
    } else if (isEmail === false) {
      Toast.show(message, {
        duration: 3000,
        position: Toast.positions.CENTER,
      })
      return
    }
    Api.h5.userSendEmailCode({ username }).then((res) => {
      if (res.code === 200) {
        setEmailId(res.data.emailId)
        Toast.show(res.message, {
          duration: 3000,
          position: Toast.positions.CENTER,
        })
        setCount(180)
        setIsSendEmail(true)
      }
    })
  }
  const handleRegister = () => {
    const { isEmail, message } = checkEmail(username)
    if (username.trim() === '') {
      Toast.show('邮箱不能为空', {
        duration: 3000,
        position: Toast.positions.CENTER,
      })
      return
    } else if (isEmail === false) {
      Toast.show(message, {
        duration: 3000,
        position: Toast.positions.CENTER,
      })
      return
    } else if (password.trim() === '') {
      Toast.show('密码不能为空', {
        duration: 3000,
        position: Toast.positions.CENTER,
      })
      return
    } else if (code.trim() === '') {
      Toast.show('验证码不能为空', {
        duration: 3000,
        position: Toast.positions.CENTER,
      })
      return
    } else if (!emailId) {
      Toast.show('请获取邮箱验证码', {
        duration: 3000,
        position: Toast.positions.CENTER,
      })
      return
    }
    Api.h5
      .userAiAdd({
        username,
        emailCode,
        emailId,
        avatar,
        nickname,
        password,
        code,
        captchaId,
      })
      .then((res) => {
        if (res.code === 200) {
          navigation.navigate('Login')
        }
      })
  }
  const handleGuest = () => {
    Api.h5.userAiGuestAdd({}, false).then((res) => {
      if (res.code === 200) {
        const { username, password } = res.data
        Api.h5
          .userAiLogin({ username, password, isGuest: true }, false)
          .then(async (res) => {
            if (res.code === 200) {
              const { username, nickname, token, talkId, uid } = res.data
              AsyncStorage.setItem('username', username)
              await AsyncStorage.setItem('nickname', nickname)
              AsyncStorage.setItem('token', token)
              AsyncStorage.setItem('talkId', talkId)
              AsyncStorage.setItem('uid', uid)
              navigation.navigate('Index', {
                type: 'home',
              })
            }
          })
      }
    })
  }
  const handleNav = (path) => {
    navigation.navigate(path)
  }
  const handleVisilbe = () => {
    setVisible(!visible)
  }
  const getCaptcha = async () => {
    Api.h5.userCaptcha({}).then((res) => {
      if (res.code === 200) {
        const { captchaId, captcha } = res.data
        let svg = captcha
        let height = svg.indexOf('height')
        let width = svg.indexOf('width')
        let step1 = svg.slice(0, height + 8)
        let step2 = svg.slice(height + 8 + 2)
        svg = `${step1}150${step2}`
        let step3 = svg.slice(0, width + 5)
        let step4 = svg.slice(width + 8 + 3)
        svg = `${step3}450${step4}`
        let html = `<div style="text-align:center;width:100%;overflow:hidden;">${svg}</div>`
        setCaptcha(html)
        setCaptchaId(captchaId)
      }
    })
  }
  const handleUploadFileCallback = (key) => {
    setAvatar(key)
  }
  useEffect(() => {
    getCaptcha()
  }, [])
  useEffect(() => {
    clearTimeout(timer)
    timer = setTimeout(() => {
      if (count > 1) {
        setCount(count - 1)
      } else {
        setIsSendEmail(false)
      }
    }, 1000)
    // eslint-disable-next-line
  }, [count])
  useEffect(() => {
    Api.h5.uploadGetTokenForH5().then(async (res) => {
      if (res.code === 200) {
        await AsyncStorage.setItem('qiniuUploadTokenForH5', res.data.token)
      }
    })
  }, [])
  return {
    username,
    emailCode,
    isSendEmail,
    count,
    avatar,
    nickname,
    password,
    code,
    visible,
    isLoading,
    captcha,
    visible1,
    usernameEl,
    setEmailCode,
    handleSendEmail,
    setNickname,
    setPassword,
    setCode,
    toggleDialog1,
    handleInput,
    handleRegister,
    handleGuest,
    handleNav,
    handleVisilbe,
    getCaptcha,
    handleUploadFileCallback,
  }
}