Dart:  Concurrency | Isolates background workers

Dart: Concurrency | Isolates background workers


2 min read

Introduction: Dart's powerful concurrency model, driven by isolates, opens up opportunities to efficiently execute tasks in the background, enhancing the responsiveness of your applications. In this blog post, we'll explore the concept of using Dart isolates as background workers, enabling developers to perform computationally intensive or time-consuming operations without affecting the main thread.

Isolate Background Workers in a Nutshell: Background workers, often implemented using isolates in Dart, allow developers to run tasks concurrently without blocking the main isolate. This is particularly useful for tasks such as complex computations, data processing, or I/O operations, ensuring a smooth and responsive user experience.

Example: Utilizing Isolate Background Workers

import 'dart:isolate';

void main() async {
  print('Main isolate starts');

  // Spawning a background worker isolate
  final ReceivePort receivePort = ReceivePort();
  final Isolate isolate = await Isolate.spawn(backgroundWorker, receivePort.sendPort);

  // Sending a message to the background worker
  receivePort.send('Perform a complex computation');

  // Listening for results from the background worker
  receivePort.listen((message) {
    print('Result from background worker: $message');

    // Terminating the background worker
    isolate.kill(priority: Isolate.immediate);

void backgroundWorker(SendPort sendPort) {
  final ReceivePort receivePort = ReceivePort();

  // Listening for messages from the main isolate
  receivePort.listen((message) {
    print('Background worker received: $message');

    // Simulating a complex computation
    final result = performComplexComputation();

    // Sending the result back to the main isolate

int performComplexComputation() {
  print('Background worker: Performing complex computation');
  // Simulating a computationally intensive operation
  for (int i = 0; i < 1000000000; i++) {
    // Perform some computation
  return 42; // Simulated result


  1. The main function spawns a background worker isolate using Isolate.spawn and sets up communication with it using a ReceivePort.

  2. The background worker isolate listens for messages from the main isolate, performs a complex computation, and sends the result back.

  3. The main isolate sends a message to the background worker, listens for the result, and terminates the background worker once the result is received.

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