On Oct 28, 2013, at 5:25 PM, Domenic Denicola wrote: > > I think the issue is that these things are properties, either because of web > legacy (as in some specifications) or because the spec writers conceptualize > them as such and are reluctant to change them (for the newer specifications). > And returning a fresh array from the getter each time is unpleasant. If they > could be changed to methods, returning a new object each time makes a lot of > sense. > > That said I feel like this is a common enough need that it might be worth the > DOM speccing a read-only proxy-onto-an-array view type that they could reuse. > As Boris says it would probably be very similar to what ArrayClass does, so > maybe ArrayClass is OK as-is, but I feel like fleshing it out in terms of > real ES proxies would make it feel less hackish, perhaps? > > (Such a type would be generally useful for not just DOM specs, IMO. Maybe I > should work on a library prototyping this and if it's awesome and everyone > loves it and uses it, someone can spec it officially.) >
So what's so onerous about returning a fresh array from the getter each time it was called. If it was implemented in Es6, it would just be: return Array.from(internal_compy); Proxies aren't cheap. Unless these arrays tend to be quite large, I wouldn't be surprised if the overhead of using a Proxy for this useless ended up being higher than the cost of making fresh arrays. Allen _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss