--description--

Given a string of credit card numbers, return a masked version of it using the following constraints:

• The string will contain four sets of four digits (0-9), with all sets being separated by a single space, or a single hyphen (-).
• Replace all numbers, except the last four, with an asterisk (*).
• Leave the remaining characters unchanged.

For example, given "4012-8888-8888-1881" return "****-****-****-1881".

--hints--

mask("4012-8888-8888-1881") should return "****-****-****-1881".

assert.equal(mask("4012-8888-8888-1881"), "****-****-****-1881");

mask("5105 1051 0510 5100") should return "**** **** **** 5100".

assert.equal(mask("5105 1051 0510 5100"), "**** **** **** 5100");

mask("6011 1111 1111 1117") should return "**** **** **** 1117".

assert.equal(mask("6011 1111 1111 1117"), "**** **** **** 1117");

mask("2223-0000-4845-0010") should return "****-****-****-0010".

assert.equal(mask("2223-0000-4845-0010"), "****-****-****-0010");

--seed--

--seed-contents--

function mask(card) {

  return card;
}

--solutions--

function mask(card) {
  const split = card.split(card.includes('-') ? '-' : ' ');
  
  return card.includes('-') ?
    `****-****-****-${split[3]}` :
    `**** **** **** ${split[3]}`;
}