Dart Academy · Lesson

Lazy Iterables and Generators With sync*

Produce values on demand.

What Lazy Means

A lazy iterable does not compute its values until you actually ask for them. Work happens on demand, not all at once. 🦥

Methods like map and where return a lazy Iterable. Nothing runs until you iterate or call toList.

var it = [1, 2, 3].map((n) {
  print('seen $n');
  return n * 2;
});