使用redux-toolkit登录createAsyncThunk和编写reducer

Question

我正在阅读createAsyncThunk文档，对流程感到有点困惑。这是文档中的内容：

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))

我需要在reducers和extraReducers中写些什么？标准的reducer逻辑？

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

Answer 1

createSlice的reducers属性允许您创建一个操作创建器函数，并在一个步骤中响应这些操作。您可以使用extraReducers来响应已在别处创建的操作，例如在异步thunk中。extraReducer只是响应一个动作，而不是创建一个动作创建器函数。

该示例说明，除了extraReducers之外，您还可以拥有一些常规的reducers。但我查看了您的CodeSandbox，在您的情况下，您不需要任何其他reducers，因为您正在响应的唯一操作是来自async thunk的三个操作。

由于您的createSlice不会创建任何操作创建器，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;
    }
  }
})