如果不需要异步更新状态，可以使用ref来保存值，而不是使用useState。

const name = useRef("John");
name.current = "Michael";
console.log(name.current); // will print "Michael" since updating the ref is not async

我写了自定义挂钩与typescript，如果有人还需要它。

import React, { useEffect, useRef, useState } from "react";

export const useStateWithCallback = <T>(initialState: T): [state: T, setState: (updatedState: React.SetStateAction<T>, callback?: (updatedState: T) => void) => void] => {
    const [state, setState] = useState<T>(initialState);
    const callbackRef = useRef<(updated: T) => void>();

    const handleSetState = (updatedState: React.SetStateAction<T>, callback?: (updatedState: T) => void) => {
        callbackRef.current = callback;
        setState(updatedState);
    };

    useEffect(() => {
        if (typeof callbackRef.current === "function") {
            callbackRef.current(state);
            callbackRef.current = undefined;
        }
    }, [state]);

    return [state, handleSetState];
}

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])

我遇到了同样的问题，在我的设置中使用useEffect没有做到这一点(我正在从一个数组多个子组件更新父组件的状态，我需要知道哪个组件更新了数据)。

在promise中包装setState允许在完成后触发任意动作:

import React, {useState} from 'react'

function App() {
  const [count, setCount] = useState(0)

  function handleClick(){
    Promise.resolve()
      .then(() => { setCount(count => count+1)})
      .then(() => console.log(count))
  }


  return (
    <button onClick= {handleClick}> Increase counter </button>
  )
}

export default App;

下面的问题让我找到了正确的方向: React在使用钩子时是否有批量状态更新功能?

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]);

我探索了use-state with-callback npm库和其他类似的自定义钩子，但最后我意识到我可以做这样的事情:

const [user, setUser] = React.useState(
  {firstName: 'joe', lastName: 'schmo'}
)

const handleFirstNameChange=(val)=> {
  const updatedUser = {
     ...user,
     firstName: val
  }
  setUser(updatedUser)
  updateDatabase(updatedUser)
}