Benchmarking creating an object

perf.js

// Creating different objects.

var z = 5;

this.group(
  "Primitives",
  function Nothing(x)   { return; },
  function Null(x)      { return null; },
  function Boolean(x)   { return true; },
  function Number(x)    { return 1; },
  function String(x)    { return ""; },
  function VarArg(x)    { return x; },
  function VarExt(x)    { return z; }
);

this.group(
  "Simple objects",
  function Object(x)    { return {}; },
  function Array(x)     { return []; },
  function Function(x)  { return function(){}; }
);

this.group(
  "Complex objects",
  function MObject(x)   { return {a: 1, b: 2, c: 3}; },
  function MArray(x)    { return [1, 2, 3]; },
  function MFunction(x) { return function(a, b, c){ return a + b + c; }; },
  function Closure(x)   { return function(a){ return a + x + z; }; }
);

this.group(
  "Builtin objects",
  function DateObj(x)   { return new Date; },
  function RegExpIn(x)  { return /\s+\w/; },
  function RegExpEx(x)  { return new RegExp("\s+\w"); }
);

Benchmark it with http://www.perfjs.com/