Flutter/Dart Benchmarks: ChangeNotifier/Cubit/StateNotifier/StreamController

aResults.md

Test	Time (Microseconds)
ValueNotifier	0.14619362615225495
StateNotifier	0.6242255
Cubit	1.2855485
StreamController	1.3412715

macOS Mac Mini - 3.2 GHz 6-Core Intel Core i7, running under Flutter Release Mode

These benchmarks attempt to compare performance of different versions of the observer pattern in Flutter. Each test emits a single value on each call and the listener uses the value to make a simple assignment call.

Disclaimer: no claims are made about the correctness of the comparisons. Please post any corrections or other feedback here.

cubit.dart

import 'package:benchmark_harness/benchmark_harness.dart';
import 'package:bloc/bloc.dart';

String counterMirror = '0';
StringCubit controller = StringCubit('0');

class StringCubit extends Cubit<String> {
  int counter = 0;
  StringCubit(super.state);
  void go() {
    //Note: this is not the normal use of Cubit but necessary
    //for compatibility with the other tests
    counter++;
    emit(counter.toString());
  }
}

class TemplateBenchmark extends BenchmarkBase {
  const TemplateBenchmark() : super('Template');

  static void main() {
    const TemplateBenchmark().report();
  }

  @override
  void run() {
    controller.go();
  }

  @override
  void setup() => controller.stream.listen((state) => counterMirror = state);

  @override
  void teardown() {}
}

void main(List<String> arguments) {
  TemplateBenchmark.main();
}

state_notifier.dart

import 'package:benchmark_harness/benchmark_harness.dart';
import 'package:state_notifier/state_notifier.dart';

int counter = 0;
String counterMirror = '0';
StringStateNotifier controller = StringStateNotifier('Hi');

class StringStateNotifier extends StateNotifier<String> {
  StringStateNotifier(super.state);

  void go() {
    counter++;
    state = counter.toString();
  }
}

class TemplateBenchmark extends BenchmarkBase {
  const TemplateBenchmark() : super('Template');

  static void main() {
    const TemplateBenchmark().report();
  }

  @override
  void run() {
    controller.go();
  }

  @override
  void setup() => controller.addListener((state) => counterMirror = state);

  @override
  void teardown() {}
}

void main(List<String> arguments) {
  TemplateBenchmark.main();
}

stream_controller.dart

import 'dart:async';
import 'package:benchmark_harness/benchmark_harness.dart';

String counterMirror = '0';

StringStreamWrapper controller = StringStreamWrapper();

class StringStreamWrapper {
  int counter = 0;
  StreamController<String> streamController = StreamController();
  void go() {
    counter++;
    streamController.add(counter.toString());
  }
}

class TemplateBenchmark extends BenchmarkBase {
  const TemplateBenchmark() : super('Template');

  static void main() {
    const TemplateBenchmark().report();
  }

  @override
  void run() {
    controller.go();
  }

  @override
  void setup() => controller.streamController.stream
      .listen((state) => counterMirror = state);

  @override
  void teardown() {}
}

void main(List<String> arguments) {
  TemplateBenchmark.main();
}

value_notifier.dart

import 'package:benchmark_harness/benchmark_harness.dart';
import 'package:flutter/material.dart';

String counterMirror = '0';

StringValueNotifier controller = StringValueNotifier('0');

class StringValueNotifier extends ValueNotifier<String> {
  int counter = 0;
  StringValueNotifier(super.state);

  void go() {
    counter++;
    notifyListeners();
  }
}

class TemplateBenchmark extends BenchmarkBase {
  const TemplateBenchmark() : super('Template');

  static void main() {
    const TemplateBenchmark().report();
  }

  @override
  void run() {
    controller.go();
  }

  @override
  void setup() =>
      controller.addListener(() => counterMirror = controller.value);

  @override
  void teardown() {}
}

void main(List<String> arguments) {
  TemplateBenchmark.main();
}

versions.md

async 2.9.0 (2.10.0 available) benchmark_harness 2.2.0 bloc 8.1.0 boolean_selector 2.1.0 (2.1.1 available) characters 1.2.1 clock 1.1.1 collection 1.16.0 (1.17.0 available) cupertino_icons 1.0.5 fake_async 1.3.1 flutter 0.0.0 from sdk flutter flutter_lints 2.0.1 flutter_test 0.0.0 from sdk flutter lints 2.0.1 matcher 0.12.12 (0.12.13 available) material_color_utilities 0.1.5 (0.2.0 available) meta 1.8.0 path 1.8.2 sky_engine 0.0.99 from sdk flutter source_span 1.9.0 (1.9.1 available) stack_trace 1.10.0 (1.11.0 available) state_notifier 0.7.2+1 stream_channel 2.1.0 (2.1.1 available) string_scanner 1.1.1 (1.2.0 available) term_glyph 1.2.1 test_api 0.4.12 (0.4.16 available) vector_math 2.1.2 (2.1.4 available)