sync vs async for loops

index.js

function* range(end) {
  for (let i = 0; i < end; i++) {
    yield i;
  }
}

const a = Array.from(range(65536));

module.exports['for await..of values from one chunk'] = {
  fn: async function(deferred) {
    let i = 0;
    for await (const _ of a) {
      i++;
    }
    deferred.resolve(i);
  },
  defer: true,
};

module.exports['for..of values from one chunk'] = {
  fn: function() {
    let i = 0;
    for (const _ of a) {
      i++;
    }
    return i;
  },
};

// executed using this code: https://github.com/iter-tools/iter-tools/blob/0a567a2ebc76b9bd32354397709f8c1c6df8e615/benchmarks/index.js

/*
$ node --version
v15.2.1
$ node ./benchmarks/
  Running 1 benchmarks, please wait...

  async vs sync for loops
    ✓  for await..of values from one chunk x 80.75 ops/sec ±1.08% (74 runs sampled)
    ✓  for..of values from one chunk x 18,382 ops/sec ±0.47% (86 runs sampled)

    Result: for..of values from one chunk is 22665.12% faster than for await..of values from one chunk.

  
Finished in 13 seconds
*/