在Redux传奇中访问Promise数据,可以通过使用中间件来处理异步操作。Redux中常用的中间件是redux-thunk和redux-saga。
使用redux-thunk的步骤如下:
npm install redux-thunk
import thunk from 'redux-thunk';
const store = createStore(reducer, applyMiddleware(thunk));
示例代码:
// 定义异步action
const fetchData = () => {
return (dispatch, getState) => {
dispatch({ type: 'FETCH_DATA_REQUEST' });
// 异步操作,例如发送网络请求获取数据
fetch('https://api.example.com/data')
.then(response => response.json())
.then(data => {
dispatch({ type: 'FETCH_DATA_SUCCESS', payload: data });
})
.catch(error => {
dispatch({ type: 'FETCH_DATA_FAILURE', payload: error });
});
};
};
// 在组件中触发异步action
import { connect } from 'react-redux';
import { fetchData } from './actions';
class MyComponent extends React.Component {
componentDidMount() {
this.props.fetchData();
}
render() {
// 根据异步操作的状态显示相应的内容
if (this.props.loading) {
return <div>Loading...</div>;
} else if (this.props.error) {
return <div>Error: {this.props.error}</div>;
} else {
return <div>Data: {this.props.data}</div>;
}
}
}
const mapStateToProps = state => ({
loading: state.loading,
error: state.error,
data: state.data
});
const mapDispatchToProps = {
fetchData
};
export default connect(mapStateToProps, mapDispatchToProps)(MyComponent);
使用redux-saga的步骤如下:
npm install redux-saga
import createSagaMiddleware from 'redux-saga';
const sagaMiddleware = createSagaMiddleware();
const store = createStore(reducer, applyMiddleware(sagaMiddleware));
sagaMiddleware.run(rootSaga);
示例代码:
// 定义异步操作的saga
import { takeLatest, call, put } from 'redux-saga/effects';
import { fetchDataSuccess, fetchDataFailure } from './actions';
function* fetchDataSaga() {
try {
const response = yield call(fetch, 'https://api.example.com/data');
const data = yield response.json();
yield put(fetchDataSuccess(data));
} catch (error) {
yield put(fetchDataFailure(error));
}
}
function* rootSaga() {
yield takeLatest('FETCH_DATA_REQUEST', fetchDataSaga);
}
// 在组件中触发异步action
import { connect } from 'react-redux';
import { fetchDataRequest } from './actions';
class MyComponent extends React.Component {
componentDidMount() {
this.props.fetchDataRequest();
}
render() {
// 根据异步操作的状态显示相应的内容
if (this.props.loading) {
return <div>Loading...</div>;
} else if (this.props.error) {
return <div>Error: {this.props.error}</div>;
} else {
return <div>Data: {this.props.data}</div>;
}
}
}
const mapStateToProps = state => ({
loading: state.loading,
error: state.error,
data: state.data
});
const mapDispatchToProps = {
fetchDataRequest
};
export default connect(mapStateToProps, mapDispatchToProps)(MyComponent);
以上是在Redux传奇中访问Promise数据的两种常用方法,具体选择哪种方法取决于项目需求和个人偏好。
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