createAsyncThunk 并使用 redux-toolkit 编写减速器登录

Question

我正在阅读createAsyncThunk文档，并对流程感到有点困惑。这是来自文档：

import { createAsyncThunk, createSlice } from '@reduxjs/toolkit'
import { userAPI } from './userAPI'

// First, create the thunk
const fetchUserById = createAsyncThunk(
  'users/fetchByIdStatus',
  async (userId, thunkAPI) => {
    const response = await userAPI.fetchById(userId)
    return response.data
  }
)

// Then, handle actions in your reducers:
const usersSlice = createSlice({
  name: 'users',
  initialState: { entities: [], loading: 'idle' },
  reducers: {
    // standard reducer logic, with auto-generated action types per reducer
  },
  extraReducers: {
    // Add reducers for additional action types here, and handle loading state as needed
    [fetchUserById.fulfilled]: (state, action) => {
      // Add user to the state array
      state.entities.push(action.payload)
    }
  }
})

// Later, dispatch the thunk as needed in the app
dispatch(fetchUserById(123))

我必须在reducers和中写什么extraReducers？标准减速器逻辑？

我有这个CodeSandbox，我用旧的 redux 方式实现了。现在，需要redux-toolkit在其中实现。

Answer 1

reducers的属性允许createSlice您使操作创建器发挥作用并一步响应这些操作。您可以extraReducers用来响应已在其他地方创建的操作，例如在异步重击中。仅extraReducer响应操作但不创建操作创建器函数。

这个例子是说reducers除了extraReducers. 但我查看了您的 CodeSandbox，在您的情况下，您不需要任何其他操作reducers，因为您响应的唯一操作是来自 async thunk 的三个操作。

由于您createSlice不会创建任何动作创建者，因此您实际上不需要使用createSlice. 您可以使用它，但也可以只使用createReducer.

import { createAsyncThunk, createSlice } from '@reduxjs/toolkit'
import { userAPI } from './userAPI'

export const fetchUserFromGithub = createAsyncThunk(
  'users/fetch',
  async (username) => {
    const response = await axios.get(
      `https://api.github.com/users/${username}`
    );
    return response.data
  }
)

const usersSlice = createSlice({
  name: 'users',
  initialState: {
    user: null,
    fetchingUser: false,
    fetchingError: null
  },
  reducers: {},
  extraReducers: {
    [fetchUserFromGithub.pending]: (state, action) => {
      state.fetchingUser = true;
      state.fetchingError = null;
    },
    [fetchUserFromGithub.rejected]: (state, action) => {
      state.fetchingUser = false;
      state.fetchingError = action.error;
    }
    [fetchUserFromGithub.fulfilled]: (state, action) => {
      state.fetchingUser = false;
      state.user = action.payload;
    }
  }
})