Async Coding With Dart: Generators

1 min readNov 10, 2019

What you are going to learn: What are Generators? How to implement a synchronous generator function? How to implement the asynchronous generator function?

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What are Generators?

Generators can create sequence of values synchronously (by this we can create Iterable) and asynchronously (by this we can create Stream).

How to implement a synchronous generator function?

There are two thing to implement sync generator:

i- Mark function with “sync*” it defines function is generator and will return Iterable.

Iterable<int> createSyncGenerator(int n) sync* {
-----------
}

ii- Use “yeild” statement to deliver value

-------------
  yield k++;
-------------

Here is example:

synchronous Generator

How to implement asynchronous generator function?

There are two thing to implement async generator:

i- Mark function with “async*” it defines function is generator and will return Stream.

Stream<int> createAsyncGenerator(int n) async* {
  -------------------
}

ii- Use “yeild” statement to emit value in stream

-------------
  yield k++;
-------------

Here is complete code:

asynchronous Generator

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