format method

String format(Decimal? amount, { bool symbols = true, bool grouping = true, bool negative = true, })

Formats the decimal amount using the currency object attached to the MoneyFormatter instance and returns the textual representation or '' if the amount is unavailable. amount for which a textual representation is returned. symbols specify true to prepend any symbol prefix or append any symbol suffix as specified by the currency object's symbolPrefix and symbolSuffix properties. grouping specify true to separate groups of digits using ',' character. negative specify true to prepend a negative sign if the amount is negative.

Implementation

String format(Decimal? amount,
    {bool symbols = true, bool grouping = true, bool negative = true}) {
  if (amount == null) {
    return '';
  }
  var s = amount.toStringAsFixed(_currency.exponent);
  var amountNegative = s.startsWith('-');
  if (grouping) {
    var whole = amountNegative ? s.substring(1) : s;
    var fractional = '';
    if (_currency.exponent > 0) {
      fractional = whole.substring(whole.length - _currency.exponent - 1);
      whole = whole.substring(0, whole.length - (_currency.exponent + 1));
    }
    if (whole.length > 3) {
      var buf = StringBuffer();
      var i = whole.length - 1;
      var count = 1;
      while (i >= 0) {
        var c = whole[i];
        buf.write(c);
        if (count % 3 == 0 && i != 0) {
          buf.write(',');
        }
        i--;
        count++;
      }
      whole = buf.toString().reverse();
    }
    s = (amountNegative ? '-' : '') + whole + fractional;
  }
  if (symbols) {
    s = s.insert(_currency.symbolPrefix, amountNegative ? 1 : 0);
    s = s + _currency.symbolSuffix;
  }
  if (!negative) {
    s = s.removePrefix('-');
  }
  return s;
}