Redux Slice

slice是应用中单个功能的 Redux reducer 逻辑和 action 的集合, 通过slice我们可以把某个功能的对应state，action，reducer一起定义在一个文件中

src/store/index.js

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import { configureStore } from "@reduxjs/toolkit"
import counterSlice from "./counterSlice"
import userSlice from "./userSlice"

const store = configureStore({
    reducer:{
        counter:counterSlice,
        user:userSlice
    }
})

export default store

src/store/counterSlice.js

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import { createSlice } from "@reduxjs/toolkit"

const initialState = {
    count:0
}

const counterSlice = createSlice({
    name:"counter",
    initialState,
    reducers:{
        increment: (state,{ payload }) =>{
            // Redux Toolkit 允许我们在 reducers 写 "可变" 逻辑。
            // 并不是真正的改变 state 因为它使用了 immer 库
            // 当 immer 检测到 "draft state" 改变时，会基于这些改变去创建一个新的
            // 不可变的 state
            state.count += payload.num
            //不需要return 更新后的state了
        },
        decrement: (state,{ payload }) =>{
            state.count -= payload.num
        }
    }
})

//导出action creator
export const { increment,decrement } = counterSlice.actions

//导出reducer
export default counterSlice.reducer

src/store/userSlice.js

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import { createSlice } from "@reduxjs/toolkit"
import findIndex from "lodash/findIndex"

const initialState = {
    user:[]
}

const userSlice = createSlice({
    name:"user",
    initialState,
    reducers:{
        addUser:(state,{ payload }) =>{
            state.user.push(payload.user)
        },
        minUser:(state,{ payload }) =>{
            let currentIndex = findIndex(state.user,element=>element.name === payload.name)
            state.user = [
                ...state.user.slice(0,currentIndex),
                ...state.user.slice(currentIndex+1)
            ]
        }
    }
})

export const { addUser,minUser } = userSlice.actions
export default userSlice.reducer

src/App.js

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import { useSelector, useDispatch } from "react-redux"
import { increment, decrement } from "./store/counterSlice"
import { addUser,minUser } from "./store/userSlice"

function App() {

  const counter = useSelector((state) => state.counter)
  const users = useSelector((state) => state.user)
  const dispatch = useDispatch()

  const clickAddHandler = () => {
    dispatch(increment({ num:10 }))
  }

  const clickMinHandler = () => {
    dispatch(decrement({ num:5 }))
  }

  const clickAddUserHandler = () =>{
    dispatch(addUser({ user:{ name:"百战" } }))
  }

  const clickMinUserHandler = () =>{
    dispatch(minUser({ name:"百战" }))
  }

  return (
    <div className="App">
      <h3>Redux Slice</h3>
      <p>Count = {counter.count}</p>
      <button onClick={clickAddHandler}>增加</button>
      <button onClick={clickMinHandler}>减少</button>
      <button onClick={clickAddUserHandler}>添加用户</button>
      <button onClick={clickMinUserHandler}>减少用户</button>
      <ul>
        {
          users.user.map((element,index) =>{
            return <li key={ index }>{ element.name }</li>
          })
        }
      </ul>
    </div>
  );
}

export default App;

action creator自动生成

createSlice 函数会自动生成与我们编写的 reducer 函数同名的 action creator，保存在slice的actions属性里面