Handling errors with redux-toolkit?

Answer

Per the docs, RTK's createAsyncThunk has default handling for errors - it dispatches a serialized version of the Error instance as action.error.

If you need to customize what goes into the rejected action, it's up to you to catch the initial error yourself, and use rejectWithValue() to decide what goes into the action:

const updateUser = createAsyncThunk(
'users/update',
async (userData, { rejectWithValue }) => {
const { id, ...fields } = userData
try {
const response = await userAPI.updateById(id, fields)
return response.data.user
} catch (err) {
if (!err.response) {
throw err
}

return rejectWithValue(err.response.data)
}
}
)