Managing Thunk States and Timeout Errors in Redux Reducer

// Define action types
const FETCH_DATA = 'FETCH_DATA';
const FETCH_DATA_SUCCESS = 'FETCH_DATA_SUCCESS';
const FETCH_DATA_ERROR = 'FETCH_DATA_ERROR';
const FETCH_DATA_TIMEOUT = 'FETCH_DATA_TIMEOUT';

// Initial state for the reducer
const initialState = {
  data: null,
  loading: false,
  error: null,
  timeout: false
};

// Example reducer handling async thunk states and timeout errors
function dataReducer(state = initialState, action) {
  switch (action.type) {
    case FETCH_DATA:
      return { ...state, loading: true, error: null, timeout: false };
    case FETCH_DATA_SUCCESS:
      return { ...state, data: action.payload, loading: false };
    case FETCH_DATA_ERROR:
      return { ...state, loading: false, error: action.error, timeout: false };
    case FETCH_DATA_TIMEOUT:
      return { ...state, loading: false, timeout: true, error: 'Timeout error' };
    default:
      return state;
  }
}