Really weird object creation JS benchmark

Question

I've made a simple object creation benchmark. I know "there are lies, damn lies and benchmarks", however the difference seems huge. Can anyone tell me if I'm doing something wrong. Or if not, how is it possible? I'm new to JS so please don't beat me.

http://jsperf.com/factoryvsconstvsobjectcreate/3

/Edit thanks Andrew Fedoniouk for a little bugfix

Answer 1

The huge difference between the Factory and Constructor tests is due to a series of extra steps performed in the latter.

When a function is invoked as a constructor, its [[Construct]] internal method is invoked, and that's likely the cause of the performance difference. Look at all the steps involved in [[Construct]]:

1. Let obj be a newly created native ECMAScript object.

2. Set all the internal methods of obj as specified in 8.12.

3. Set the [[Class]] internal property of obj to "Object".

4. Set the [[Extensible]] internal property of obj to true.

5. Let proto be the value of calling the [[Get]] internal property of F with argument "prototype".

6. If Type(proto) is Object, set the [[Prototype]] internal property of obj to proto.

7. If Type(proto) is not Object, set the [[Prototype]] internal property of obj to the standard built-in Object prototype object as described in 15.2.4.

8. Let result be the result of calling the [[Call]] internal property of F, providing obj as the this value and providing the argument list passed into [[Construct]] as args.

9. If Type(result) is Object then return result.

10. Return obj.