type Path = (string | number)[];

// Converts the fields to a query string.
export function query(
  fields: Record<string, string | undefined | null>,
): string {
  const search = new URLSearchParams();

  // Ignore undefined and null values.
  for (const key in fields) {
    if (fields[key] !== undefined && fields[key] !== null) {
      search.set(key, fields[key]!);
    }
  }
  search.sort();

  let s = search.toString();
  if (s !== "") {
    s = "?" + s;
  }
  return s;
}