Comparison of List.[] and List.elementAt.

index_lookup_benchmark.dart

main() async {
  var list = [for (var i = 0; i < 10000; i++) i.isEven ? i : -i];
  for (var i = 0; i < 5; i++) {
    print("elementAt : ${bench1(list)}/ms");
    await Future((){}); // Don't block browser.
    print("operator[]: ${bench2(list)}/ms");
    await Future((){});
  }
}

double bench1(List<int> list) {
  var c = 0, e = 0;
  var result = 0;
  var sw = Stopwatch()..start();
  do {
    for (int i = 0; i < list.length; i++) {
      result += list.elementAt(i);
    }
    c += 1;
    e = sw.elapsedMilliseconds;
  } while (e < 2000);
  if (result == 0) throw "whoops";
  return (c * list.length)/e;
}

double bench2(List<int> list) {
  var c = 0, e = 0;
  var result = 0;
  var sw = Stopwatch()..start();
  do {
    for (int i = 0; i < list.length; i++) {
      result += list[i];
    }
    c += 1;
    e = sw.elapsedMilliseconds;
  } while (e < 2000);
  if (result == 0) throw "whoops";
  return (c * list.length)/e;
}