How to flatten a List?

Question

How can I easily flatten a List in Dart?

For example:

var a = [[1, 2, 3], [\'a\', \'b\', \'c\']         


        

Answer 1

the solution with expand method fits good to satisfy this case :

expect(ListTools.getFlatList([[1],["hello",2],["test"]]),orderedEquals([1,"hello",2,"test"]));

But not for theses ones

expect(ListTools.getFlatList([[1],["hello",2,["foo",5]],["test"]]),orderedEquals([1,"hello",2,"foo",5,"test"]));
expect(ListTools.getFlatList([1,["hello",2],"test"]),orderedEquals([1,"hello",2,"test"]));

To satisfy theses test cases, you need something more recursive like the following function :

List getFlatList(List list) {
  List internalList = new List();
  list.forEach((e) {
    if (e is List) {
      internalList.addAll(getFlatList(e));
    } else {
      internalList.add(e);
    }
  });
  return internalList;
}

Best regards,

Sébastien