Dart, compare chat messages id in list to show avatar

main.dart

 final list = [
    Message(0), Message(0), Message(0),
    Message(1), Message(1),
    Message(0),
    Message(2), Message(2), Message(2),
    Message(0),
    Message(3), Message(3),
    Message(1), Message(1),
    Message(4),
    Message(0)
  ];


void main() {
  Message prevMessage, currMessage;
  for (var i = 0; i < list.length; ++i) {
    currMessage = list[i];
    if (i > 0) prevMessage = list[i - 1];
    prevMessage?.compareShowAvatar(currMessage);
  }
  currMessage?.compareShowAvatar(prevMessage);

  list.forEach(print);
}


class Message {
  int uid;
  bool showAvatar = false;

  Message(this.uid);

  void compareShowAvatar(Message other) => showAvatar=other?.uid != uid;

  @override
  String toString() => 'Message {uid: $uid, showAvatar: $showAvatar}';
}