我不认为用useRef区分挂载与否是一个好方法，不是一个更好的方法来确定useState()在useEffect()中生成的值是否为初始值?

const [val, setVal] = useState(null)

useEffect(() => {
  if (val === null) return
  console.log('not mounted, val updated', val)
}, [val])

您需要使用useEffect钩子来实现这一点。

const [counter, setCounter] = useState(0);

const doSomething = () => {
  setCounter(123);
}

useEffect(() => {
   console.log('Do something after counter has changed', counter);
}, [counter]);

如果你想在第一次初始渲染时忽略useEffect回调，那么相应地修改代码:

import React, { useEffect, useRef } from 'react';

const [counter, setCounter] = useState(0);
const didMount = useRef(false);

const doSomething = () => {
  setCounter(123);
}

useEffect(() => {
  // Return early, if this is the first render:
  if ( !didMount.current ) {
    return didMount.current = true;
  }
  // Paste code to be executed on subsequent renders:
  console.log('Do something after counter has changed', counter);
}, [counter]);

如果你想要更新之前的状态，那么你可以在hooks中这样做:

const [count, setCount] = useState(0);


setCount(previousCount => previousCount + 1);

简单的解决方案，只需安装

我使用-state-with-callback

import React from 'react';
import { useStateWithCallbackLazy } from "use-state-with-callback";

const initialFilters = {
  smart_filter: "",
};

const MyCallBackComp = () => {
  const [filters, setFilters] = useStateWithCallbackLazy(initialFilters);

  const filterSearchHandle = (e) => {
    setFilters(
      {
        ...filters,
        smart_filter: e,
      },
      (value) => console.log("smartFilters:>", value)
    );
  };

  return (
    <Input
      type="text"
      onChange={(e) => filterSearchHandle(e.target.value)}
      name="filter"
      placeholder="Search any thing..."
    />
  );
};

认为: 反应usestate回调

我们可以写一个叫做useScheduleNextRenderCallback的钩子，它返回一个“schedule”函数。在我们调用setState之后，我们可以调用“schedule”函数，传递一个我们希望在下次呈现时运行的回调。

import { useCallback, useEffect, useRef } from "react";

type ScheduledCallback = () => void;
export const useScheduleNextRenderCallback = () => {
  const ref = useRef<ScheduledCallback>();

  useEffect(() => {
    if (ref.current !== undefined) {
      ref.current();
      ref.current = undefined;
    }
  });

  const schedule = useCallback((fn: ScheduledCallback) => {
    ref.current = fn;
  }, []);

  return schedule;
};

使用示例:

const App = () => {
  const scheduleNextRenderCallback = useScheduleNextRenderCallback();

  const [state, setState] = useState(0);

  const onClick = useCallback(() => {
    setState(state => state + 1);
    scheduleNextRenderCallback(() => {
      console.log("next render");
    });
  }, []);

  return <button onClick={onClick}>click me to update state</button>;
};

简化的测试用例:https://stackblitz.com/edit/react-ts-rjd9jk

这个怎么样:

const [Name, setName] = useState("");
...
onClick={()=>{
setName("Michael")
setName(prevName=>{...}) //prevName is Michael?
}}