sequence-conversion-custom-iterator.html

<!DOCTYPE html>
<html>
<body>
<script src="../resources/runner.js"></script>
<script>
let dataArray = [];
for (let i = 0; i < 100000; i++)
  dataArray.push('');

let iterableData = {
  [Symbol.iterator]() {
    var count = 0;
    return {
      next() {
        if (count >= dataArray.length)
          return {done: true};
        return {done: false, value: dataArray[count++]};
      }
    }
  }
};

PerfTestRunner.measureRunsPerSecond({
  description: "This benchmark measures the overhead of converting JavaScript objects into WebIDL sequences (slow path using the @@iteratorprotocol)",
  run: function() {
    new Blob(iterableData);
  }});
</script>
</body>
</html>

chromium/third_party/blink/perf_tests/bindings/sequence-conversion-custom-iterator.html