Easy to use isolates for Dart and Flutter.

Usage

Almost as easy to use as Dart's built-in compute function, but using a long-lived isolate.

Example:

void main() async {
  final statefulIsolate = StatefulIsolate();
  print(await statefulIsolate.compute(_isPrime, 7));
  print(await statefulIsolate.compute(_isPrime, 42));
  statefulIsolate.dispose();
}

bool _isPrime(int value) {
  if (value == 1) {
    return false;
  }
  for (int i = 2; i < value; ++i) {
    if (value % i == 0) {
      return false;
    }
  }
  return true;
}

Remember to always dispose once you are done using the isolate to clean up and close the isolate:

statefulIsolate.dispose();

Specialized/tailored isolates

If you know the input and output types for the stateful isolate at creation time you can use a TailoredStatefulIsolate. They work the exact same way as the StatefulIsolate, but declares at creation time what types are supported as input and output of the compute functions.

Example:

void main() async {
  // This isolate only takes `int` as input and returns `bool`.
  final statefulIsolate = TailoredStatefulIsolate<int, bool>();
  print(await statefulIsolate.compute(_isPrime, 7));
  print(await statefulIsolate.compute(_isPrime, 42));
  statefulIsolate.dispose();
}

Handling backpressure

If you hammer the stateful isolate with too many calls that takes too long to run, your memory will eventually run out as the compute call stack keeps growing. A way to handle that is to set a backpressure strategy when creating the isolate.

There are a few different backpressure strategies supported out of the box. To use them just declare which one to use when creating the stateful isolate:

final isolate = StatefulIsolate(backpressureStrategy: DiscardNewBackPressureStrategy());

Currently supported strategies can be found in the documentation.

Additional information

The API of this package is not final, and is subject to change.

Breaking change

• integral_isolates v0.5.0: Renamed compute functions to isolate.compute(..) and isolate.computeStream(..).
• integral_isolates v0.4.0: deprecated the class Isolated in favor of StatefulIsolate. The class TailoredStatefulIsolate was also added, adding support for an isolate that allows for specifying input and output types.

Are you using flutter_hooks?

Try the use_isolate package that controls the lifecycle of the isolate, so you don't have to.