How do I combine two lists in Dart?

You can use:

var newList = new List.from(list1)..addAll(list2);

If you have several lists you can use:

var newList = [list1, list2, list3].expand((x) => x).toList()

As of Dart 2 you can now use +:

var newList = list1 + list2 + list3;

As of Dart 2.3 you can use the spread operator:

var newList = [...list1, ...list2, ...list3];

maybe more consistent~

var list = []..addAll(list1)..addAll(list2);

If you want to merge two lists and remove duplicates could do:

var newList = [...list1, ...list2].toSet().toList(); 

Dart now supports concatenation of lists using the + operator.

Example:

List<int> result = [0, 1, 2] + [3, 4, 5];