Dart translation from https://github.com/wardaLyns/EMVCoParser

emvco_parser.dart

// EMVCoParser Dart translation from https://github.com/wardaLyns/EMVCoParser

class EMVCoParser {
  static final int length = 2;

  String emvcoQrValue;
  int tag, subTag;
  bool hasSubTag;

  EMVCoParser(String emvcoQrValue, int tag) {
    this.emvcoQrValue = emvcoQrValue;
    this.tag = tag;
  }

  EMVCoParser.withSubtag({String emvcoQrValue, int tag, int subTag}) {
    this.emvcoQrValue = emvcoQrValue;
    this.tag = tag;
    this.subTag = subTag;
    hasSubTag = true;
  }

  String getParsingValue() {
    Map<int, EmvObject> parsingValues = parseEmvcoQR(emvcoQrValue);
    EmvObject obj = parsingValues[this.tag];
    if (hasSubTag) {
      return parseEmvcoQR(obj.getValues())[this.subTag].getValues();
    }
    return obj.getValues();
  }

  Map<int, EmvObject> parseEmvcoQR(String str) {
    Map<int, EmvObject> result = new Map<int, EmvObject>();
    int i = 0;

    while (i < str.length) {
      int tagInd = i + length;

      int tag = int.parse(str.substring(i, tagInd));
      int lengthValue = int.parse(str.substring(tagInd, tagInd + length));

      EmvObject emvObject = new EmvObject();
      emvObject.setLength(lengthValue);
      emvObject.setValues(str.substring(tagInd + length, tagInd + length + lengthValue));

      print("Index Tag/SubTag : " +
          tagInd.toString() +
          " Length : " +
          lengthValue.toString() +
          " Values " +
          str.substring(tagInd + length, tagInd + length + lengthValue));
      // result.put(tag, emvObject);
      result.putIfAbsent(tag, () => emvObject);

      i = tagInd + length + lengthValue;
    }

    return result;
  }
}

class EmvObject {
  int length;
  String values;

  int getLength() {
    return length;
  }

  void setLength(int length) {
    this.length = length;
  }

  String getValues() {
    return values;
  }

  void setValues(String values) {
    this.values = values;
  }

  // bool equals(EmvObject o) {
  //   // if (this == o) return true;
  //   // if (o == null || getClass() != o.getClass()) return false;

  //   EmvObject emvObject = o;

  //   if (length != emvObject.length) return false;
  //   // return values != null ? values.equals(emvObject.values) : emvObject.values == null;
  //   return (values != null) ? values.compareTo(emvObject.values) : emvObject.values == null;
  // }

  // // @override
  // int hashCode() {
  //   int result = length;
  //   result = 31 * result + (values != null ? values.hashCode : 0);
  //   return result;
  // }
}

Thank you very much sir!