Thanks for the useful information, Sven!
In my case, I have many instances of the same kind of object. In order to
cut down on garbage collection at runtime, I created a pool that contains
all instances. When I'm done with an instance, instead of freeing the
reference and letting it be GC'd, I put it back into the pool so that I can
reuse it.
I thought it would be a good idea to set all default primitive values on
the prototype so that only the properties that were actually set would be
created as local properties: the rest would be defaults shared across all
instances.
When I put something back into the pool, I wanted to delete all local
properties to "clean" the instance for reuse. Based on what you are saying,
it seems that for performance I should NOT delete the properties, but
rather maintain a set of all default properties on each instance, and then
null them out.
Followup question based on the above: in a constructor when I establish all
of my local properties, is it better to set them to default null value or
to a default value of the same type that I intend to use for it (such as
empty string, integer, etc.): does the value assigned to a local property
in the constructor effect the way optimization will occur for the property?
Thanks very much!
On Thursday, May 31, 2012 11:34:07 PM UTC-7, Zenwolf wrote:
>
> Greetings all,
>
> Does using the JavaScript "delete" keyword to delete a property from an
> object effect how v8 will optimize the object? I've read that v8 creates
> hidden "classes" to represent an object and all its various property
> configurations. Does deleting a property just flip between two of these
> hidden classes and is it less efficient than just nulling the local
> property value?
>
> Secondly, how will v8 handle the case where I have a prototype object with
> "name" property and also a local property "name" and I delete the local
> property to expose the prototype value again?
>
> Example:
>
> function Foo() {
> this.name = 'foo';
> }
>
> function Bar() {}
> Bar.prototype = new Foo();
> var bar = new Bar();
> bar.name = 'bar';
> // later in the program...
> delete bar.name; // exposes prototype name again (Foo's name).
>
> Will using delete in such a manner prevent v8 from fully optimizing the
> code? Or should I not worry about this usage?
>
> Thank you very much for any insight!
>
>
On Thursday, May 31, 2012 11:34:07 PM UTC-7, Zenwolf wrote:
>
> Greetings all,
>
> Does using the JavaScript "delete" keyword to delete a property from an
> object effect how v8 will optimize the object? I've read that v8 creates
> hidden "classes" to represent an object and all its various property
> configurations. Does deleting a property just flip between two of these
> hidden classes and is it less efficient than just nulling the local
> property value?
>
> Secondly, how will v8 handle the case where I have a prototype object with
> "name" property and also a local property "name" and I delete the local
> property to expose the prototype value again?
>
> Example:
>
> function Foo() {
> this.name = 'foo';
> }
>
> function Bar() {}
> Bar.prototype = new Foo();
> var bar = new Bar();
> bar.name = 'bar';
> // later in the program...
> delete bar.name; // exposes prototype name again (Foo's name).
>
> Will using delete in such a manner prevent v8 from fully optimizing the
> code? Or should I not worry about this usage?
>
> Thank you very much for any insight!
>
>
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