pagination-queryPaginated.ts

export function queryPaginated<T>(http: HttpClient, baseUrl: string, urlOrFilter?: string | object): Observable<Page<T>> {
  let params = new HttpParams();
  let url = baseUrl;

  if (typeof urlOrFilter === 'string') {
    // we were given a page URL, use it
    url = urlOrFilter;
  } else if (typeof urlOrFilter === 'object') {
    // we were given filtering criteria, build the query string
    Object.keys(urlOrFilter).sort().forEach(key => {
      const value = urlOrFilter[key];
      if (value !== null) {
        params = params.set(key, value.toString());
      }
    });
  }

  return http.get<Page<T>>(url, {
    params: params
  });
}