---------- Forwarded message ---------- From: Xavier MONTILLET <[email protected]> Date: Fri, Sep 30, 2011 at 7:20 PM Subject: Re: Proposal: Storage for getters and setters To: Dean Landolt <[email protected]>
Alright... So it'll store it with the object as key... It's really a good idea since you could create a polyfill that just generates an object with a toString returning some random string and therefore making collision nearly impossible. I just tryed implementing it with proxies but when the traps are called, the object has already turned into a string :/ On Fri, Sep 30, 2011 at 6:52 PM, Dean Landolt <[email protected]> wrote: > > > On Fri, Sep 30, 2011 at 12:26 PM, Xavier MONTILLET <[email protected]> > wrote: >> >> > Maybe it could use more example use cases. What you're proposing above >> > could also be done by keeping the private value in a closure, but if you > >> > need to hang it off the object this gives you a way to do that safely. >> Well yes a closure works if you want a value for an object... but as >> soon as you start having several instances, you need to either not use >> the prototype or do some some arrays and store values in them... and >> it kind of sucks... > > > Sure. That's when it helps to be able to hang any old key off the proto in a > way that's guaranteed not to collide. This is what private names give you. > You only need to generate one name object per class, and you can keep this > name object anywhere you'd like, so long as your getter and setter have > access. They interact with `this` by way of the name object, and your > private state is stored on the instance, completely silently (unless some > kind of "visibility flag" came to pass -- then you could choose to expose it > to all but still gain the benefits of name collision avoidance). > >> >> I still don't understand how the thing in the link you psoted works... >> var s = {}; >> undefined >> var o = {}; >> undefined >> var o2 = {}; >> undefined >> s[ o ] = 1; >> 1 >> s[ o2 ]; >> 1 > > It certainly won't work in an es-current shell. What we've got here is a > coercion fail -- you're using the string key '[object Object]' in `s`. You'd > need to use an actual private name object -- and AFAIK no such > implementation exists. > Does anyone know of one in the works? I suspect it's blocked by a > harmony-modules implementation. And this is a real shame -- like proxies and > weak maps this shouldn't need to wait on modules -- otherwise it's just new > semantics, not syntax. Anyone have ideas on how to get around this? Would it > be so bad to piss a little more in the Object.* namespace pool? It's already > pretty yellow, and the chances of an Object.PrivateName collision are > remote. _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
