Proper way to handle errors in redux using redux-promise - redux

Question

I'm trying "redux-promise".
When there's no error in the flow, my code works properly. But, let's say that the API is down or I have a typo in the URL. In those cases, I expect to handle the error in the proper way.
This is the API: https://jsonplaceholder.typicode.com/users
(in the snippet I'm adding random text at the end to produce the 404)
Action creator
export async function fetchUsers() {
const request = await axios
.get('https://jsonplaceholder.typicode.com/userssdfdsfdsf')
.catch(error => console.log('ERROR', error))
return {
type: FETCHING_USERS,
payload: request
};
}
Reducer
export default (state = [], action) => {
switch (action.type) {
case FETCHING_USERS:
return [...state, ...action.payload.data]
default:
return state
}
}
I can see the error logged in the console
ERROR Error: Request failed with status code 404
But, once the action is dispatched its payload is undefined
action {type: "FETCHING_USERS", payload: undefined}
I don't know where is the best place to handle this: action creator, reducer, etc. I shouldn't check if payload is something in the reducer and, if not, return state or do nothing. I want to understand which would be the best approach to handle this.

Answer 1

You may look at source of redux-promise, as it very simple.
Redux-promise expects either promise or action with payload set to some promise. I think you're going to use leter case.
Code may look like (just example, not tested):
export function fetchUsers() {
const request = axios.get('https://jsonplaceholder.typicode.com/userssdfdsfdsf');
return {
type: FETCHING_USERS,
payload: request
};
}
In this case redux-promise will await for resolution of promise returned by axios.get and dispatch your action but payload replaced with promise result. In case of error, redux-promise will catch it and dispatch action with error = true (you may want to handle action.error === true case in reducer)

Answer 2

In the reducer you should check for the existence of the error field in action:
export default function(state = null, action) {
if (action.error) {
//handle
}
switch(action.type) {

Answer 3

This code is for the action.
export const fetchUsers = () => async dispatch => {
try {
const res = await axios.get('https://jsonplaceholder.typicode.com/userssdfdsfdsf');
dispatch({
type: FETCHING_USERS,
payload: res.data
});
} catch (err) {
dispatch({
type: FETCHING_ERROR
});
}
};
In reducer do this.
Define the initial state and use this code.
export default function(state = initialState, action) {
const { type, payload } = action;
switch (type) {
case FETCHING_USERS:
return {
...state,
loading: false,
user: payload,
};
case FETCH_ERROR:
return {
...state,
token: null,
loading: false,
};