1.8 KiB
1.8 KiB
title |
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Use Middleware to Handle Asynchronous Actions |
Use Middleware to Handle Asynchronous Actions
Hint 1
Treat the dispatch
argument as a function and pass the action events in it.
Hint 2
The requestingData
action event will be passed first.
Hint 3
The receivedData
action event will be passed after the setTimeout
function.
This sequence simulates the process of requesting the data, receiving the data and then dispatching the received data.
Hint 4
It is important that the data
variable be passed as an argument of receivedData
.
Solution
const REQUESTING_DATA = 'REQUESTING_DATA'
const RECEIVED_DATA = 'RECEIVED_DATA'
const requestingData = () => { return {type: REQUESTING_DATA} }
const receivedData = (data) => { return {type: RECEIVED_DATA, users: data.users} }
const handleAsync = () => {
return function(dispatch) {
// dispatch request action here
dispatch(requestingData());
setTimeout(function() {
let data = {
users: ['Jeff', 'William', 'Alice']
}
// dispatch received data action here
dispatch(receivedData(data));
}, 2500);
}
};
const defaultState = {
fetching: false,
users: []
};
const asyncDataReducer = (state = defaultState, action) => {
switch(action.type) {
case REQUESTING_DATA:
return {
fetching: true,
users: []
}
case RECEIVED_DATA:
return {
fetching: false,
users: action.users
}
default:
return state;
}
};
const store = Redux.createStore(
asyncDataReducer,
Redux.applyMiddleware(ReduxThunk.default)
);