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34 lines
762 B
34 lines
762 B
import { useState } from 'react'
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function getDefaultValue () {
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for (let i = 0; i < 10000; i++) {
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}
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return '10'
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}
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function Counter (props) {
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const [count, setCount] = useState(() => {
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/**
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* 初始值经过一定的计算：
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* 只要无法直接确定，需要通过一定的操作才能获取，就可以理解为计算
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*/
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// return props.count
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// 循环遍历一万条数据才能确定这里的初始值
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return getDefaultValue()
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})
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return (
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<button onClick={() => setCount(count + 1)}>{count}</button>
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)
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}
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function App () {
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return (
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<div>
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<Counter count={10}/>
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<Counter count={20}/>
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</div>
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)
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}
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export default App
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