我现在正在学习redux。下面共享的代码独立于 React，因此不考虑 React 集成。
下面是 redux-basics.js，它有Reducer、Store、Action 和 Subscription部分
const redux = require('redux');
const createStore = redux.createStore;
// Note : Store Creation is actually dependent on Reducer Thats why reducer must be created first.
// Reducer
const initialState = { counter : 0}
const rootReducer = (state = initialState,action) => {
if(action.type === 'INCR_COUNTER'){
return { ...state,
counter : state.counter + 1 }
}
if(action.type === 'ADD_COUNTER'){
return { ...state,
counter : state.counter + action.value }
}
return state;
}
// Store
const store = createStore(rootReducer);
console.log(store.getState())
// Subscription
store.subscribe(() => {
console.log(" SUbscription " , store.getState() );
})
// Despatching an Action
store.dispatch({type : "INCR_COUNTER"});
store.dispatch({type: "ADD_COUNTER",
value : 10
});
console.log(store.getState());
然后我得到如下输出（这是正确的！）：
Ps-MBP:redux--01-start pramod$ node redux-basics.js
{ counter: 0 }
SUbscription { counter: 1 }
SUbscription { counter: 11 }
{ counter: 11 }
但是，当我将侦听器移到调度方法下方时，订阅将不起作用？我正在尝试我缺少的东西，或者为什么会这样？我正在做的代码如下：（我以为它会打印订阅方法输出，但事实并非如此）
// Despatching an Action
store.dispatch({type : "INCR_COUNTER"});
store.dispatch({type: "ADD_COUNTER",
value : 10
});
// Subscription
store.subscribe(() => {
console.log(" SUbscription " , store.getState() );
})
console.log(store.getState())
进行上述代码转换后，代码输出如下：
Pramod:redux--01-start pramod$ node redux-basics.js
{ counter: 0 }
{ counter: 11 }
任何提示/想法为什么会这样？
慕容708150
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