Quick currency formatter implementation test

main.dart

import 'dart:math';
import 'package:intl/intl.dart';

void main(List<String> arguments) {
  // Intl.defaultLocale = 'es_AR';
  Intl.defaultLocale = 'en_US';

  //  Should be calculated only on locale change to modify the separators.
  // -- start static implementation.
  var base = NumberFormat.currency(decimalDigits: 1, symbol: '');
  var formato = base.format(1000.1);
  var decimalSep = formato[5];
  var thousandSep = formato[1];
  // -- end of static

  // utility method
  String formatCurrency(
      {int decimals = 2, int amount, String prefix, String suffix}) {
    prefix ??= '';
    suffix ??= '';
    var intValue = '';
    var units = amount / pow(10, decimals);
    var units_arr = '$units'.split('.');

    var intList = units_arr.first.split('');
    var len = intList.length - 1;
    for (var i = 0; i <= len; ++i) {
      intValue += intList[i];
      if ((len - i) % 3 == 0 && i != len) intValue += thousandSep;
    }

    // integer part
    var output = '$prefix$intValue';

    var decValue = units_arr[1];
    if (decValue != '0') {
      if (decValue.length > decimals) {
        decValue = decValue.substring(0, decimals);
      } else {
        decValue = decValue.padRight(decimals, '0');
      }

      output += decimalSep + decValue;
    }

    output += '$suffix';

    print(output);
    
    return output;
  }

  formatCurrency(decimals: 2, amount: 1001231231, prefix: '\$ ', suffix: ' s/IVA');
}