“dua titik panah” Kode Jawaban

dua titik panah

.. is known as cascade notation. 
It allows you to not repeat the same target if you want to call several methods on the same object.

List list = [];
list.add(color1);
list.add(color2);
list.add(color3);
list.add(color4);

// with cascade

List list = [];
list
  ..add(color1)
  ..add(color2)
  ..add(color3)
  ..add(color4);