isolate_plus

A modernized fork of the discontinued dart-archive/isolate package, updated to support Dart SDK 3.3.0 and above.

About This Fork

The original isolate package was discontinued by the Dart team. This fork (isolate_plus) aims to:

• ✅ Support modern Dart SDK versions (3.3.0+)
• ✅ Maintain compatibility with the latest Dart language features
• ✅ Fix compatibility issues with newer Dart SDK APIs (e.g., RawReceivePort.keepIsolateAlive)
• ✅ Provide continued maintenance and updates

Overview

Helps with isolates and isolate communication in Dart. Requires the dart:isolate library being available. Isolates are not available for Dart on the web.

The package contains individual libraries with different purposes.

Quick Start

Using IsolateRunner

Run functions in a separate isolate with easy-to-use API:

import 'package:isolate_plus/isolate_runner.dart';

// Computation function (can be top-level or static)
int expensiveWork(int value) {
  // Simulate heavy computation
  return value * value;
}

void main() async {
  // Spawn an isolate
  final runner = await IsolateRunner.spawn();
  
  // Run functions in the isolate
  final result = await runner.run(expensiveWork, 42);
  print('Result: $result'); // Result: 1764
  
  // Close when done
  await runner.close();
}

Using LoadBalancer

Distribute work across multiple isolates automatically:

import 'package:isolate_plus/load_balancer.dart';

int heavyTask(int n) {
  // Some CPU-intensive work
  return List.generate(n, (i) => i * i).reduce((a, b) => a + b);
}

void main() async {
  // Create a load balancer with 4 isolates
  final balancer = await LoadBalancer.create(4, IsolateRunner.spawn);
  
  // Run tasks in parallel across isolates
  final results = await Future.wait([
    balancer.run(heavyTask, 1000),
    balancer.run(heavyTask, 2000),
    balancer.run(heavyTask, 3000),
  ]);
  
  print('Results: $results');
  
  // Close when done
  await balancer.close();
}

Features

Creating send ports and responding to messages

The "ports.dart" sub-library contains functionality for creating SendPorts and reacting to values sent to those ports.

Key utilities include:

• singleCallbackPort / singleCallbackPortWithTimeout - Create a port that calls a callback once with the first message
• singleCompletePort - Create a port that completes a Completer with the first message
• singleResponseFuture / singleResponseFutureWithTimeout - Create a Future completed by a single port message
• singleResultFuture - Handle future results sent across isolates
• SingleResponseChannel - A reusable pattern for single-message request-response communication
• sendFutureResult - Send a future's result (value or error) across isolates

Working with isolates and running functions in other isolates

The "isolate_runner.dart" sub-library introduces an IsolateRunner class that gives easy access to the Isolate functionality, and also gives a way to run new functions in the isolate repeatedly, instead of just on the initial spawn call.

A central registry for values that can be used across isolates

The "registry.dart" sub-library provides a way to create an object registry, and give access to it across different isolates.

Balancing load across several isolates

The "load_balancer.dart" sub-library can manage multiple Runner objects, including IsolateRunner, and run functions on the currently least loaded runner.

Migration from isolate package

If you're migrating from the original isolate package, simply update your pubspec.yaml:

dependencies:
  isolate_plus: ^2.2.0  # Instead of isolate: ^2.1.1

And update your imports:

// Old
import 'package:isolate/isolate.dart';

// New
import 'package:isolate_plus/isolate_plus.dart';

The API remains fully compatible with the original package.

Issues and Contributions

Please file feature requests and bugs at the issue tracker.