code: function (n1, n2) {
              var isOk1 = _isNumber(n1),
                  isOk2 = _isNumber(n2);
              
              if (isOk1 && isOk2) {
                  // both are finite numbers
                  return (n1 - n2);
              }
              else if (isOk1)
                  return -1;
              else if (isOk2)
                  return 1;
              else
                  return 0;
          }
docs: Compare two numbers.