sumOfDigits method

int sumOfDigits()

Returns the sum of digits of this number (integer part only).

123.sumOfDigits() // 6

Implementation

int sumOfDigits() {
  var n = toInt().abs();
  var sum = 0;
  while (n > 0) {
    sum += n % 10;
    n ~/= 10;
  }
  return sum;
}