main.dart

//singleton

class User{
  
  static final User _user = User._private();
  
  User._private(){}
  
  factory User.singleton(int ids){
    return _user;
  }
}


void main(){
  
  var data = User.singleton(1);
  
  var data2 = User.singleton(2);
  
  print(data == data2); // true
  
}