standard-usecase.ts

class Users {
  list[]: string;
  loading: boolean;
  
  constructor() {
    this.list = [];
    this.loading = false;
  }
}
  
const initialState = new Users();

function usersReducer(state = initialState, action: Action) {
  switch (action.type) {
    case 'USERS_LIST_REQUEST':
      return { ...state, loading: true };  
    case 'USERS_LIST_SUCCESS':
      return { ...state, list: action.payload.list, loading: false };  
    case 'USERS_LIST_FAILED':
      return { ...state, loading: false };
  }

  return state;
}