我有一个SFC
,没有反映出Redux
存储区中的更改。减速器在 onClick 事件上被击中,但是SFC
不会更新。请不要以为我什么都不知道。我仍然是React
堆栈的新手,并且可能犯了一个愚蠢的错误。我已连接到商店,所以为什么组件不更新?我以为道具会被传入。
证监会
const Dogs = props => (
<div>
<Button variant="contained" onClick={() => props.dispatch(fetchDog())}>
Show Dog
</Button>
{props.loading ? ( // <<< PROPS ARE ALWAYS UNDEFINED
<p>Loading...</p>
) : props.error ? (
<p>Error, try again</p>
) : (
<p>
<img src={props.url} />
</p>
)}
</div>
);
const mapStateToProps = state => ({
url: state.url,
loading: state.loading,
error: state.error
});
export default connect(mapStateToProps)(Dogs);
减速器
import {
REQUESTED_DOG,
REQUESTED_DOG_SUCCEEDED,
REQUESTED_DOG_FAILED
} from "../actions/index";
// Reducer
const initialState = {
url: "",
loading: false,
error: false
};
const dog = (state = initialState, action) => {
switch (action.type) {
case REQUESTED_DOG:
return {
url: "",
loading: true,
error: false
};
case REQUESTED_DOG_SUCCEEDED: // <<< WORKS AS INTENDED!
return {
url: action.url,
loading: false,
error: false
};
case REQUESTED_DOG_FAILED:
return {
url: "",
loading: false,
error: true
};
default:
return state;
}
};
export default dog;
路由/链接
const Root = ({ store }) => (
<Provider store={store}>
...
<Switch>
<Route exact path="/" component={Home} />
<Route exact path="/dogs" component={Dogs} />
{/* <Route
path="/dogs"
render={props => (
<Dogs
url={props.url}
error={props.error}
loading={props.loading}
{...props}
/>
)}
/> */}
商店
import { createStore, applyMiddleware, compose } from "redux";
import { createLogger } from "redux-logger";
import rootReducer from "../reducers";
import DevTools from "../containers/DevTools";
import createSagaMiddleware from "redux-saga";
import { watchFetchDog } from "../sagas/dogSaga";
const logger = createLogger({
duration: true
});
const sagaMiddleware = createSagaMiddleware();
const configureStore = preloadedState => {
const store = createStore(
rootReducer,
preloadedState,
compose(
applyMiddleware(sagaMiddleware, logger), // logger must be the last middleware in chain
DevTools.instrument()
)
);
sagaMiddleware.run(watchFetchDog);
if (module.hot) {
// Enable Webpack hot module replacement for reducers
module.hot.accept("../reducers", () => {
store.replaceReducer(rootReducer);
});
}
return store;
};
export default configureStore;
Root Reducer
import { combineReducers } from "redux";
import agents from "./agents";
import visibilityFilter from "./visibilityFilter";
import theme from "./theme";
import dog from "../reducers/dog";
const rootReducer = combineReducers({
agents,
visibilityFilter,
theme,
dog
});
export default rootReducer;
答案 0 :(得分:2)
您可能错误地使用了[5, 1]
函数。您最有可能在全局环境中拥有一种狗状态。因此,一定是这样的:
max([5, 1])
评论后更新
是的,这是打开状态或组件状态的一种很好的标准方法。由于商店中没有单一状态,因此应在此处专门使用所需的状态。
现在您的商店中有一个全局mapStateToProps
,并且在此全局const mapStateToProps = state => ({
url: state.dog.url,
loading: state.dog.loading,
error: state.dog.error
});
中有多个要合并的状态,例如state
等