map performance benchmark

main.dart

void main() {
  bench('version 1', () {
    get1();
  });
  bench('version 2', () {
    get2();
  });
}

Map<String, dynamic> get1() {
  return {
    'a': 1,
    'b': 2,
    'c': 3,
    'd': 4,
  };
}

Map<String, dynamic> get2() {
  final map = <String, dynamic>{};
  map['a'] = 1;
  map['b'] = 2;
  map['c'] = 3;
  map['d'] = 4;
  return map;
}

void bench(String name, void Function() f,
    {int times = 200000, bool sum = true}) {
  for (var i = 0; i < times / 2; i++) {
    f();
  }
  final s = Stopwatch()..start();
  for (var i = 0; i < times; i++) {
    f();
  }
  s.stop();
  var time = formatTime(s.elapsedMicroseconds ~/ (sum ? 1 : times));
  print("$name: $time");
}

String formatTime(int microseconds) {
  if (microseconds < 5000) {
    return '${microseconds}µs';
  } else if (microseconds < 1000000) {
    return '${microseconds / 1000}ms';
  } else {
    return '${microseconds / 1000000}s';
  }
}