gistfile1.js

var NanoTimer = require('nanotimer');
var timing = new NanoTimer();

d = {};
i = 10000;
while (i > 0) {
  d[i] = true;
  i --;
}

oldf = function(d) {
    var values = [];
    for (var value in d) {
      values.push(value);
    }
    return d.length;
  }

newf = function(d) {
  return Object.keys(d).length;
}


run_many_times = function(fn) {
  return function() {
    var i = 1000;
    while (i > 0) {
      fn(d);
      i--;
    }
  }
}

console.log("timing started...")

var microsecs = timing.time(run_many_times(oldf));
console.log("old:");
console.log(microsecs);

var microsecs = timing.time(run_many_times(newf));
console.log("new:");
console.log(microsecs);

gistfile2.sh

st-smardenfeld1:statsd_smarden1 smardenfeld$ node ./set_timing.js
timing started...
old:
[ 0, 904347709 ]
new:
[ 0, 347407343 ]
st-smardenfeld1:statsd_smarden1 smardenfeld$ node ./set_timing.js
timing started...
old:
[ 0, 834463074 ]
new:
[ 0, 367127422 ]