This script compares the performance of constructing an object with a bunch of methods from within a function and returning it, versus using a constructor with a prototype and the 'new' keyword.

gistfile1.js

//
// This script compares the performance of constructing an object
// with a bunch of methods from within a function and returning it,
// versus using a constructor with a prototype and the 'new' keyword.
//

// My results:
//
// node, v0.8.9:
//   N = 1000000
//   simple constructor   605ms
//   real constructor     34ms
//
// Chromium 
//   N = 1000000
//   simple constructor   555ms
//   real constructor     22ms 

var N = 1000000;

console.log('N = ' + N);

function bench(name, block) {
  var start = new Date();
  for(var i=0;i<N;i++) {
    block();
  }
  var end = new Date();
  var time = end.getTime() - start.getTime()
  while(name.length < 20) {
    name += ' ';
  }
  console.log(name + ' ' + time + 'ms');
}

var simpleConstructor = function() {
  return {
    a: function() {},
    b: function() {},
    c: function() {},
    d: function() {},
    e: function() {},
    f: function() {},
    g: function() {},
    h: function() {},
    i: function() {},
    j: function() {},
    k: function() {},
    l: function() {},
    m: function() {},
    n: function() {},
    o: function() {},
    p: function() {},
    q: function() {},
    r: function() {},
    s: function() {},
    t: function() {}
  }
};

var RealConstructor = function() {};
RealConstructor.prototype = {
  a: function() {},
  b: function() {},
  c: function() {},
  d: function() {},
  e: function() {},
  f: function() {},
  g: function() {},
  h: function() {},
  i: function() {},
  j: function() {},
  k: function() {},
  l: function() {},
  m: function() {},
  n: function() {},
  o: function() {},
  p: function() {},
  q: function() {},
  r: function() {},
  s: function() {},
  t: function() {}
};

bench('simple constructor', function() {
  simpleConstructor();
});

bench('real constructor', function() {
  new RealConstructor();
});