Dart - Trying to understand the value of 'factory' constructor

Question

If I am understanding correctly:

\"A factory constructor affords an abstract class to be 
    instantiated by another class, despite being abstract.\" 
         


        

Answer 1

The one characteristic of a factory constructor is that the object is not already created at the method start. In the method you can have various mechanisms to create the object, like for example:

abstract class Animal {
  String makeNoise(String sound);
  String chooseColor(String color);
  factory Animal() {
    var random = new math.Random();
    if (random.nextBool() == true) 
      return new Cat();
    else
      return new Dog();
  }
}