text: export const appReducer = (state, action) => {
    switch (action.type) {
      case "LOG_IN":
        return {
          ...state,
          signedIn: true,
          userName: action.payload,
        };
      case "LOG_OUT":
        return { ...state, signedIn: false, userName: null, coverPhoto: null };
      case "CHANGE_COVER_PHOTO":
        return { ...state, coverPhoto: action.payload };
      case "CHANGE_PROFILE_PHOTO":
        return { ...state, profilePhoto: action.payload };
      default:
        return state;
    }
  };
  