Driver code
let s = " " ; document . write ( primeDigits ( s ) + " " ) ; s = " " ; document . write ( primeDigits ( s ) + " " ) ; s = " " ; document . write ( primeDigits ( s ) + " " ) ; s = " " ; document . write ( primeDigits ( s ) + " " ) ; s = " " ; document . write ( primeDigits ( s ) + " " ) ;