own keys benchmarking

keys-bench.js

var Benchmark = require( 'benchmark' );

var len = process.argv[2] || 3;

var obj = {};

for ( var i = 0; i < len; i++ ) {
  obj[i] = "value" + i;
}

function noop () {}

function forInKeys ( obj ) {
  for ( var key in obj ) {
    if ( obj.hasOwnProperty( key ) ) {
      noop( key );
    }
  }
}

function forKeys ( obj ) {
  var keys = Object.keys( obj );
  var len = keys.length;
  for ( var i = 0; i < len; i++ ) {
    noop( keys[i] );
  }
}

function forEachKeys ( obj ) {
  Object.keys( obj ).forEach( noop );
}


var events = [];

var suite = new Benchmark.Suite();

suite
.add( "for keys", function () {
  forKeys( obj );
})
.add( "for in & has own", function () {
  forInKeys( obj );
})
.add( "keys forEach", function () {
  forEachKeys( obj );
})
.on( 'start', function () {
  console.log( 'Hang tight, running benchmarks...' );
})
.on( 'cycle', function ( event ) {
  events.push( event );
  process.stdout.write( '.' );
})
.on( 'complete', function () {
  process.stdout.write( '\n' );

  var runs = this.slice().sort( function ( a, b ) {
    return a.hz - b.hz;
  });

  var fastest = runs.pop();
  console.log( fastest.name + " is fastest." );
  console.log( String( fastest ) );
  var run, diff, pct;

  while ( runs.length ) {
    run = runs.pop();
    diff = fastest.hz - run.hz;
    pct = ( diff * 100 / fastest.hz ).toFixed( 2 );
    console.log( run.name + " is " + pct + "% slower than fastest.");
    console.log( String( run ) );
  }
})
.run();