有两种方式仅供参考

// 第一种方式

import { useEffect, useState } from 'react'

const HelloWorld = () => {
  const [count, setCount] = useState(0)

  useEffect(() => {
    const timer = setInterval(() => {
      setCount(pre => pre + 1)
    }, 1000)

    return () => clearInterval(timer)
  }, [])

  return <p>{count}</p>
}

export default HelloWorld

// 第二种方式不推荐
// 首先 eslint 会提示把 count 当做依赖项
// 其次会频繁调用创建定时器和销毁定时器，但是也可用

import { useEffect, useState } from 'react'

const HelloWorld = () => {
  const [count, setCount] = useState(0)

  useEffect(() => {
    const timer = setInterval(() => {
      setCount(count + 1)
    }, 1000)

    return () => clearInterval(timer)
  }, [count])

  return <p>{count}</p>
}