export function sortByKey<T, K extends keyof T>(array: Array<T> , key: K, descending: boolean = false): Array<T> {
  return array.sort((a: T, b: T) => {
      const x = a[key];
      const y = b[key];
      const result = ((x < y) ? -1 : ((x > y) ? 1 : 0));
      return descending ? -result : result;
  });
}