Arrow functions上發(fā)布的類似問題只能訪問由 useReducer 創(chuàng)建的初始狀態(tài)，不能訪問更新狀態(tài)但不能解決。狀態(tài) (useReducer) 未反映在箭頭函數(shù)中。一個(gè)簡(jiǎn)單的例子：React 組件const Component = ({ children }: Props) => {    const [state, dispatch] = useReducer(reducer, {visitor: false}) useEffect(() => {    someObject = new Connection({    onMessage: msg    onSuccess: () => dispatch({type: "Visitor", value: true})    })    return () => console.log("UNMOUNTING ");  }, []);    const msg = (request) => {        // visitor: false        console.log(state) // expected updated state, but instead see initial state, why?        // ... do more things    }    // visitor: true    console.log(state) // updated state is present here    return (        <Component.Provider value={{ state }}>            {children}        </Component.Provider>    )}減速機(jī)功能：const reducer = (state, action) => {    switch (action.type) {        case 'Visitor':          return {...state, visitor: true}        default:          return state    }}