入门

npm

npm install redux-saga

yan

yarn add redux-saga

pnpm

pnpm add redux-saga

假设我们有一个UI，可以通过单击按钮从远程服务器获取一些用户数据：

import {useAppDispatch} from "@/hooks";

function App() {
    const appDispatch = useAppDispatch()
    const buttonHandler = () => {
        appDispatch({type: 'increment'})
    }
    return (
        <>
            <button onClick={buttonHandler}>increment</button>
        </>
    )
}

export default App

组件向Store派发一个普通的Object操作。我们将创建一个Saga来监视所有USER_FETCH_REQUESTED操作，并触法API调用来从远程服务器获取用户数据。

import {takeEvery, call, put} from "redux-saga/effects";

function* rootSaga() {
    yield takeEvery("USER_FETCH_REQUESTED", fetchUser)
}


export default rootSaga;

const fetchUserById = async (userId: number) => {
    return await fetch(`/api/users/${userId}`)
        .then(response => response.json())
}

function* fetchUser(action: Record<string, any>) {
    try {
        const user: Record<string, any> = yield call(fetchUserById, action.payload);
        yield put({type: "USER_FETCH_SUCCEEDED", user: user});
    } catch (e: any) {
        yield put({type: "USER_FETCH_FAILED", message: e.message});
    }
}

要运行 Saga，我们必须使用redux-saga中间件将其连接到 Redux Store。

import {configureStore, type Middleware} from "@reduxjs/toolkit";
import createSagaMiddleware from "redux-saga";
import logger from 'redux-logger'
import userReducer from "@/store/userSlice";
import rootSaga from "@/store/rootSaga.ts";

const sagaMiddleware = createSagaMiddleware()
const store = configureStore({
    reducer: {
        user: userReducer
    },
    devTools: import.meta.env.MODE !== 'production',
    middleware: (getDefaultMiddleware) => getDefaultMiddleware().concat(sagaMiddleware, logger as Middleware)
})

sagaMiddleware.run(rootSaga)

export default store

现在我们点击按钮，就可以在网络请求面板中，看到发送出了一条请求。