This is a type safe replacement for lodash _.orderBy

example.ts

// use like:
items.sort(orderBy<WorkGroup>([x => x.priorityScore, x => x.sortTime], ['desc', 'asc']);

typesafeorderby.ts

type Sortable = number | Date | string;
type Direction = "asc" | "desc";
type SortPredicate<T> = (x: T) => Sortable;
export function orderBy<T>(
  predicates: SortPredicate<T>[] = [],
  directions: Direction[] = []
) {
  if (predicates.length === 0) {
    predicates = [(x) => (x as unknown) as Sortable];
  }
  const sort = (
    a: T,
    b: T,
    p: SortPredicate<T>,
    ps: SortPredicate<T>[],
    direction: Direction,
    ds: Direction[]
  ): number => {
    const dir =
      direction === "asc"
        ? (x: Sortable, y: Sortable) => x > y
        : (x: Sortable, y: Sortable) => x < y;
    if (!p) {
      return 0;
    }
    if (dir(p(a), p(b))) {
      return 1;
    }
    if (dir(p(b), p(a))) {
      return -1;
    }
    return sort(a, b, ps[0], ps.slice(1), ds[0], ds.slice(1));
  };
  return (a: T, b: T) =>
    sort(
      a,
      b,
      predicates[0],
      predicates.slice(1),
      directions[0],
      directions.slice(1)
    );
}