UsersListState.ts

interface UsersListState {
  users: User[];
  columns: string[];
}
class UsersListStore extends ComponentStore<UsersListState> {
  // ...
  getUsers() {
    return this.select(state => state.users).pipe(
      combineLatestWith(this.select(state => state.columns)),
      map(([users, columns]) => {
        const renderedUsersList: User[] = [];
        for (let user of users) {
          let mapped = {};
          for (let column of columns) {
            mapped[column] = user[column];
          }
          renderedUsersList.push(mapped);
        }
        //  "users" were not modified here
        return renderedUsersList;
      })
    );
  }
// ... 
}
  
@Component({
  selector: 'users-list',
  template: `
            <div *ngFor="let user of users$|async">
             {{user.name}}
            </div> ...
            `
})
class UsersListComponent {
  public readonly users$: Observable<Users[]>;
  constructor(private readonly store: UsersListStore) {
    this.users$ = this.store.getUsers();
  }
}