cached vs non-cached perf

cached-loops.js

const LOOPS = 1e6;
const LEN = 1e3;

function test(fn) {
  let i = 0;
  const data = new Array(LEN);
  const start = Date.now();
  for (; i < LOOPS; i++) {
    fn(data);
  }
  const end = Date.now() - start;
  console.log('elapsed: ', end);
  console.log('op/s ', LOOPS * LEN * 1000 / end);
}

function foo(data) {
  var i=0, len=data.length, res=[];
  for (; i < len; i++) {
    res[i] = true;
  }
  return res;
}

function bar(data) {
  var res=[];
  for (var i=0; i < data.length; i++) {
    res[i] = true;
  }
  return res;
}

console.log('cached loop---');
test(foo);
console.log('non-cached loop---');
test(bar);