javascript - React useReducer 不更新状态

Question

当用户登录但失败时，我使用 useReducer 更新 errorsState。我读过很多解决方案，据说 dispatch 是异步的，我知道这一点，所以我将 console.log 放在 useEffect 中查看errorsState 发生了变化，但不幸的是它没有改变。这是我的代码

登录.jsx

export default function Login({ userProps }) {
  //
  // some variables and state
  //
  const { loading, user } = useLogin({ email: state.email }, state.submitted)
  const [errors, dispatch] = useReducer(errorsReducer, errorsState)

  useEffect(() => {
    console.log("errors", errors) // it won't triggered because errors state didn't updating from UseLogin
  }, [errors])

  return content
}

这是获取函数useLogin

AuthAction.js

export const useLogin = (data, submitted) => {
  const [state, dispatch] = useReducer(userReducer, userState)
  const [errors, errorsDispatch] = useReducer(errorsReducer, errorsState)

  useEffect(() => {
    if (!submitted) return

    dispatch({
      type: USER_ACTIONS.MAKE_REQUEST,
    })

    ticketApi.login(data).then(({ res, status }) => {
      if (status !== "failed") {
        // Save to local storage
        const { token } = res
        // set token to local storage
        localStorage.setItem("jwtToken", token)
        // Set token to Auth Header
        setAuthToken(token)
        // decode token to get user data with jwt-decode
        const decoded = jwt_decode(token)
        // set current user
        return dispatch({
          type: USER_ACTIONS.GET_USER,
          payload: decoded,
        })
      }

      dispatch({
        type: USER_ACTIONS.END_REQUEST,
      })

      return errorsDispatch({
        type: ERRORS_ACTIONS.GET_ERRORS,
        payload: res.response.data,
      })
    })
  }, [submitted])

  return state
}

我尝试将 console.log 放入 ERRORS_ACTIONS.GET_ERRORS 中以查看响应，效果很好。 那么我哪里出错了？

Answer 1

useReducer 允许您更好地管理复杂的状态，它不是一个状态容器，您所做的是创建 2 个不同的状态，一个在 useLogin 内，另一个在 useLogin 内在 Login 组件中的其他部分，从 useLogin Hook 返回 errors，以便 Login 组件可以看到它。

登录

export default function Login({ userProps }) {
  //
  // some variables and state
  //
  const { loading, user, errors } = useLogin({ email: state.email }, state.submitted)

  useEffect(() => {
    console.log("errors", errors)
  }, [errors])

  return content
}

使用登录

export const useLogin = (data, submitted) => {
  const [state, dispatch] = useReducer(userReducer, userState)
  const [errors, errorsDispatch] = useReducer(errorsReducer, errorsState)

  useEffect(() => {
    if (!submitted) return

    dispatch({
      type: USER_ACTIONS.MAKE_REQUEST,
    })

    ticketApi.login(data).then(({ res, status }) => {
      if (status !== "failed") {
        // Save to local storage
        const { token } = res
        // set token to local storage
        localStorage.setItem("jwtToken", token)
        // Set token to Auth Header
        setAuthToken(token)
        // decode token to get user data with jwt-decode
        const decoded = jwt_decode(token)
        // set current user
        return dispatch({
          type: USER_ACTIONS.GET_USER,
          payload: decoded,
        })
      }

      dispatch({
        type: USER_ACTIONS.END_REQUEST,
      })

      return errorsDispatch({
        type: ERRORS_ACTIONS.GET_ERRORS,
        payload: res.response.data,
      })
    })
  }, [submitted])

  return { ...state, errors };
}