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import { useEffect, useState } from 'react'
function Test () {
useEffect(() => {
let timer = setInterval(() => {
console.log('定时器执行了')
}, 1000)
return () => {
// 清理定时器
clearInterval(timer)
}
}, [])
return (
<div>this is test</div>
)
}
function App () {
const [flag, setFlag] = useState(true)
return (
<div>
{flag ? <Test /> : null}
<button onClick={() => setFlag(!flag)}>switch</button>
</div>
)
}
export default App