React 钩子状态未在日志中更新 [英] React hooks states aren't updating in log

问题描述

如果我写

function Component() {
  const [isLoading, setLoading] = useState(true);
  const request = () => {
    setLoading(true)
    console.log(isLoading)
    setLoading(false)
    console.log(isLoading)
  }
}

它两次都会注销true".为什么控制台中的状态没有更新?尽管它在 DOM 中运行良好.

It will log out 'true' both times. Why isn't the state updating in the console? Eventhough it works fine in the DOM.

this.setState({ ...} 将显示新的状态值

推荐答案

使用 setState 或 useState 钩子在 state 中设置新值是一个异步过程.

Setting a new value in state by using setState or useState hook is an asynchronous process.

如果你想在它改变后记录新值，你必须将它与useEffect钩子结合

If you want to log the new value once it has changed, you have to couple it with the useEffect hook

useEffect(() => {
  console.log(isLoading)
}, [isLoading]);

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