Difference between yield and yield* in Dart

Question

I wanted to know what's the difference between this two. I find this SO post on javascript, Delegated yield (yield star, yield *) in generator functions

From what I understand, yield* delegates to the another generator and after the another generator stop producing values, then it resumes generating its own values.

Explanation and examples on the dart side would be helpful.

Answer 1

yield

It is used to emit values from a generator either async or sync.

Example:

Stream<int> str(int n) async* {   for (var i = 1; i <= n; i++) {     await Future.delayed(Duration(seconds: 1));     yield i;   } }  void main() {   str(3).forEach(print); } 

Output:

1 2 3 

---

yield*

It delegates the call to another generator and after that generator stops producing the values, it resumes generating its own values.

Example:

Stream<int> str(int n) async* {   if (n > 0) {       await Future.delayed(Duration(seconds: 1));     yield n;     yield* str(n - 1);   } }  void main() {   str(3).forEach(print); } 

Output:

3 2  1