What features of the Dart language explain its single-threaded nature?

Dart is a single-threaded language because its execution model is based on the event loop and isolates.

Main reasons for Dart's single-threaded nature:

• Event Loop: Dart uses an event processing loop that executes tasks sequentially and handles asynchronous operations without creating new threads.

• Isolates: For parallelism, Dart uses isolates — separate memory areas with their own thread of execution. Isolates do not share memory and communicate via messages, preventing synchronization issues.

Thus, Dart's main thread is single-threaded, simplifying development and reducing the likelihood of errors related to multithreading. Heavy computations or parallel work are done in isolates.

Example of creating an isolate:

import 'dart:isolate';

void isolateFunction(SendPort sendPort) {
  sendPort.send('Hello from isolate');
}

void main() async {
  ReceivePort receivePort = ReceivePort();
  await Isolate.spawn(isolateFunction, receivePort.sendPort);

  receivePort.listen((message) {
    print(message); // Will print: Hello from isolate
    receivePort.close();
  });
}