reactjs - 与 ComponentWillMount 等效的 React 钩子(Hook)

Question

我看了一下here但所选答案不回答问题。我正在寻找 componentWillMount()相当于执行类似的逻辑:

useEffect(() => {
  if (condition) {
    // do stuff
  }
}, []);

上面的问题是组件在执行 useEffect 之前呈现一瞬间。代码块。

有什么办法可以解决这个问题？没有 useEffect 在主 App 中运行组件或创建自定义 Hook ？

Answer 1

来自 reactjs 文档:

This lifecycle was previously named componentWillMount. That name will continue to work until version 17. Use the rename-unsafe-lifecycles codemod to automatically update your components.

UNSAFE_componentWillMount() is invoked just before mounting occurs. It is called before render(), therefore calling setState() synchronously in this method will not trigger an extra rendering. Generally, we recommend using the constructor() instead for initializing state.

所以没有更多的等价于componentWillMount，您可以修改render方法以返回null/placeholder，直到满足您的init条件并在useEffect中设置状态。你也可以看看 react 悬念。