オブジェクト型の配列の重複した要素を削ったものがほしかったので作成

dedupe.dart

List<S> dedupe<T, S>(List<S> values, T Function(S) key) {
  var valuesSet = <T>{};
  List<S> results = [];
  for (var element in values) {
    if (!valuesSet.contains(key(element))) {
      valuesSet.add(key(element));
      results.add(element);
    }
  }
  return results;
}

void main() {
  final List<Hoge> hogeList = [Hoge(id: "1", body:"テキスト１"),
                               Hoge(id: "2", body:"テキスト2"), 
                               Hoge(id: "3", body:"テキスト3"),
                              Hoge(id: "4", body:"テキスト4"),
                              Hoge(id: "5", body:"テキスト5")];
  
   final List<Hoge> addList = [Hoge(id: "2", body:"テキスト2"), 
                               Hoge(id: "3", body:"テキスト3"),
                              Hoge(id: "6", body:"テキスト6"),
                              Hoge(id: "7", body:"テキスト7")];
  
  // 2つの配列を結合
  hogeList.addAll(addList);
  
  final dedupeList = dedupe(hogeList, (Hoge element) => element.id);
  
  
  print(dedupeList);
}

class Hoge {
  String id;
  String body;
  Hoge({required this.id, required this.body});
  
  @override
  String toString() {
    return 'Hoge: {id: ${id}, body: ${body}}';
  }
}