Whether an object's prototype is changed from JavaScript or from C++ doesn't make a difference. (Why would it?)
The preferred way to set a newly allocated object's prototype is to use the FunctionTemplate's PrototypeTemplate. See the large comment for class FunctionTemplate in v8.h. On Fri, Feb 12, 2016 at 5:44 AM, Zac Hansen <xax...@gmail.com> wrote: > I want to do the equivalent of Object.create() in javascript from C++, but > I don't see any way to specify the prototype of a new v8::Object from the > API. > > I was planning on creating the object with v8::Object::New and then > calling v8::Object::SetPrototype() on it, until I saw this: > > > https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/setPrototypeOf > > Warning: Changing the [[Prototype]] of an object is, by the nature of how > modern JavaScript engines optimize property accesses, a very slow > operation, in *every* browser and JavaScript engine. The effects on > performance of altering inheritance are subtle and far-flung, and are not > limited to simply the time spent in obj.__proto__ = ... statement, but > may extend to *any* code that has access to *any* object whose > [[Prototype]] has been altered. If you care about performance you should > avoid setting the [[Prototype]] of an object. Instead, create a new > object with the desired [[Prototype]] using Object.create() > <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/create> > . > > > That's a pretty terrifying situation, so I want to make sure that using > SetPrototype() doesn't incur that kind of penalty - at least on a newly > created and unused object. > > Thank you. > > --Zac > > -- > -- > v8-users mailing list > v8-users@googlegroups.com > http://groups.google.com/group/v8-users > --- > You received this message because you are subscribed to the Google Groups > "v8-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to v8-users+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
