Regex validate PIN code

7 kyu
Regex validate PIN code

ATM machines allow 4 or 6 digit PIN codes and PIN codes cannot contain anything but exactly 4 digits or exactly 6 digits.

If the function is passed a valid PIN string, return true, else return false.

Examples
"1234"   -->  true
"12345"  -->  false
"a234"   -->  false


function validatePIN (pin) {
  return /^(\d{4}|\d{6})$/.test(pin)
}