const matcher =
  /^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$/;

export function isEmail(string?: string): boolean {
  if (!string) return false;
  if (string.length > 320) return false;
  return matcher.test(string);
}