How to get axios error response INTO the redux saga catch method - axios

Question

With axios the code is:
export const createBlaBla = (payload) => {
return axios.post('/some-url', payload)
.then(response => response)
.catch(err => err);
}
And then I'm using this with redux-saga like this:
function* createBlaBlaFlow(action) {
try {
const response = yield call(createBlaBla, action.payload);
if (response) {
yield put({
type: CREATE_BLA_BLA_SUCCESS
});
}
} catch (err) {
// I need the error data here ..
yield put({
type: CREATE_BLA_BLA_FAILURE,
payload: 'failed to create bla-bla'
});
}
}
In case of some error on the backend - like invalid data send to the backend - it returns a 400 response with some data:
{
"code":"ERR-1000",
"message":"Validation failed because ..."
"method":"POST",
"errorDetails":"..."
}
But I don't receive this useful data in the catch statement inside the saga. I can console.log() the data in the axios catch statement, also I can get it inside the try statement in the saga, but it never arrives in the catch.
Probably I need to do something else? ... Or the server shouldn't return 400 response in this case?

Answer 1

So, I came up with two solutions of this problem.
===
First one - very dump workaround, but actually it can be handy in some specific cases.
In the saga, right before we call the function with the axios call inside, we have a variable for the errors and a callback that sets that variable:
let errorResponseData = {};
const errorCallback = (usefulErrorData) => {
errorResponseData = usefulErrorData;
};
Then - in the axios method we have this:
export const createBlaBla = (payload, errCallback) => {
return axios.post('/some-url', payload)
.then(response => response)
.catch(err => {
if (err && err.response.data && typeof errCallback === 'function') {
errCallback(err.response.data);
}
return err;
});
}
This way, when we make request and the backend returns errors - we'll call the callback and will provide the errors from the backend there. This way - in the saga - we have the errors in a variable and can use it as we want.
===
However, another solution came to me from another forum.
The problem I have is because in the method with the axios call I have catch, which means that the errors won't bubble in the generator. So - if we modify the method with the axios call like this:
export const createBlaBla = (payload) => {
return axios.post('/some-url', payload)
}
Then in the catch statement in the saga we'll have the actual backend error.
Hope this helps someone else :)

Answer 2

In your API call you can do the following:
const someAPICall = (action) => {
return axios.put(`some/path/to/api`, data, {
withCredentials: true,
validateStatus: (status) => {
return (status == 200 || status === 403);
}
});
};
Please note the validateStatus() part - this way when axios will encounter 200 or 403 response, it will not throw Error and you will be able to process the response after
const response = yield call(someAPICall, action);
if (response.status === 200) {
// Proceed further
} else if (response.status === 403) {
// Inform user about error
} else {
...
}