[英]redux connect mapStateToProps not called when action is dispatched
解決方案(更新):
我以為任何動作都會導致react-redux-connect調用mapState函數,但是當一個動作什么都沒有改變時,事實並非如此。
我有一個localStorage模塊,該模塊可以調度操作,但不更改狀態,相反,您會寫入localStorage。 該模塊具有在容器中使用的選擇器,但是直到狀態實際更改時它們才被調用,因此,只有在分派了另一個更改狀態的操作之后,UI才能正確顯示。
問題
當我將商店放在窗口( window.store=store
)上時,在mapStateToProps中添加console.log,然后在控制台中分派一個動作: store.dispatch({type:'some action'})
然后是控制台。 mapStateToProps的日志不顯示。
我確實記住了結果,但是應該調用mapStateToProps, 請參見此處
完整的代碼在這里 ,運行示例在這里 (您可以單擊屏幕右下角的“控制台”鏈接打開控制台)。
store.js:
import { createStore } from 'redux';
export default (initialState, reducer) => {
const store = createStore(
reducer,
initialState,
window.__REDUX_DEVTOOLS_EXTENSION__ &&
window.__REDUX_DEVTOOLS_EXTENSION__()
);
window.store = store;
return store;
};
app.js
import React from 'react';
import { connect } from 'react-redux';
import './App.css';
import createStore from './store';
import { Provider } from 'react-redux';
import initCounter from './components/Counter';
import {
createWrapper,
memoize,
} from './components/@common';
const COUNTER = 'COUNTER';
const selectCounterState = state => state.myCounter;
const counter = initCounter({
actionWrapper: createWrapper(COUNTER, 'counter1'),
selectors: { myState: selectCounterState },
connect,
memoize,
});
const initialState = {
myCounter: counter.initialState,
};
const reducer = (state = initialState, action) => {
if (action.emittedBy === COUNTER) {
return {
...state,
myCounter: counter.reducer(
selectCounterState(state),
action.payload
),
};
}
return state;
};
const store = createStore(initialState, reducer);
const Counter = counter.container;
const App = () => (
<Provider store={store}>
<Counter id="counter1" parentId={[]} />
</Provider>
);
export default App;
組件/計數器/索引:
import component from './component';
const INCREASE = 'INCREASE';
const reducer = (state, action) => {
if (action.type === INCREASE) {
return { ...state, count: state.count + 1 };
}
return state;
};
const makeState = memoize =>
memoize((id, parentId, { count }) => ({
id: parentId.concat(id),
parentId,
count,
}));
const mapStateToProps = ({ myState }, memoize) => () => {
const newState = makeState(memoize);
return (state, ownProps) =>
console.log('in map state to props', new Date()) ||
newState(
ownProps.id,
ownProps.parentId,
myState(state)
);
};
export default ({
actionWrapper,
selectors,
connect,
memoize,
}) => {
const actions = {
increase: ({ id }) =>
actionWrapper({
type: INCREASE,
id,
}),
};
const container = connect(
mapStateToProps(selectors, memoize),
actions
)(component);
return {
container,
reducer,
initialState: { count: 0 },
};
};
組件/計數器/ component.js:
import React from 'react';
export default props => (
<div>
<button onClick={() => props.increase(props)}>
add
</button>
{props.count}
</div>
);
您的示例代碼筆工作得很好,您只需觸發一個超出頂級警衛並且具有預期結構的操作即可,以免引起任何后續錯誤:
將其發布到您的Codepen控制台中:
store.dispatch({emittedBy: "COUNTER", type: "COUNTER -> INCREASE", id: "counter1", payload: {type: "INCREASE", id: ["counter1"]}})
造成此問題的原因是,我有一個localStorage模塊,該模塊執行調度操作,但未更改狀態,而是將其寫入localStorage。
該模塊具有選擇器,這些選擇器將獲取正確的數據,並且容器將使用它們來構建正確的狀態,但是由於分派的操作並未更改redux存儲中的狀態,因此react-redux會跳過調用我的mapState函數(可能在Provider中記住狀態) )。
解決方案是讓根縮減器返回新的狀態引用{...state}
以便任何操作都會導致mapState函數被調用。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.