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async & async* difference

Magnificent Moose answered on May 15, 2023 Popularity 7/10 Helpfulness 1/10

answer async & async* difference

async & async* difference

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// Async functions execute synchronously until they reach the await keyword. 
// Therefore, all synchronous code within an async function body executes 
// immediately. Async* is used to create a function that returns a bunch of future values 
// one at a time. Each result is wrapped in a Stream.

// Example : 

// for async
Future<int> doSomeLongTask() async { //async keyword for a () that works' might take a long time.
   await Future.delayed(const Duration(seconds: 1));
   return 42;
}
main() async {
  int result = await doSomeLongTask();
  print(result); // prints '42' after waiting 1 second
}

// for async*
Stream<int> countForOneMinute() async* { //async* keyword for making the () returning future values one at a time.
  for (int i = 1; i <= 60; i++) {
    await Future.delayed(const Duration(seconds: 1));
    yield i; //yield to return a value instead of return bcz it doesnt leaving the function.
  }
}
main() async {
  await for (int i in countForOneMinute()) { //await for to wait for each value emitted by the Stream.
    print(i); // prints 1 to 60, one integer per second
  }
}

Popularity 7/10 Helpfulness 1/10 Language dart

Source: stackoverflow.com

Tags: dart difference

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Contributed on May 15 2023

Magnificent Moose

0 Answers Avg Quality 2/10

async & async* difference

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