Read esdiscuss.org, use Google site: search, before complaining that you don't understand why something is not "enabled". Here's a link:
https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=site%3Aesdiscuss.org%20weak%20reference It's not hard to find the full history of the discussion. /be On Thu, Nov 5, 2015 at 12:41 AM Romuald Quantin <[email protected]> wrote: > Someone made an experiment with the Mozilla “getWeakReference” apparently. > > https://gist.github.com/Benvie/7123690 > > https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Language_Bindings/Components.utils.getWeakReference > > I had this as granted with other languages, I still don’t understand why > has this not been enabled by default in javascript. > > On 4 November 2015 at 22:54, Coroutines <[email protected]> wrote: > >> On Wed, Nov 4, 2015 at 2:36 PM, Rick Waldron <[email protected]> >> wrote: >> >> > On Wed, Nov 4, 2015 at 8:16 AM Coroutines <[email protected]> wrote: >> >> >> obj[Symbol.weakValues] = true; >> >> obj[Symbol.weakProperties] = true; >> >> > 2. For security purposes, only code that has been explicitly given >> access to >> > _both_ the weakmap and a key may gain access to the value stored within >> the >> > weakmap. This is why there is no enumeration—if there were, then any >> code >> > that could access the weakmap could then also access all of the keys and >> > values. If that's a desirable trait, then just use a Map. >> > >> > These things cannot be done with Proxy, because anything that Proxy does >> > will inevitably be a strongly held reference. >> >> Well, you explained the mystery behind why WeakMap can't be iterated >> over - but I was saying I would combine Proxy with a theoretical >> Symbol for marking keys and/or values as weakly-referenced to create >> WeakSet and WeakMap (if I wanted). I think I just prefer Lua in this >> area: >> >> local tmp = setmetatable({ 'a', 'b', 'c' }, { __mode = 'v' }) >> >> for k, v in ipairs(tmp) do >> print(k, v) >> end >> >> 'a', 'b', and 'c' are weakly-referenced and can be iterated over, will >> be marked by the next GC step, and will not survive the next GC >> collection cycle. I wish JS let me create weak references as simply: >> >> var tmp = [ 'a', 'b', 'c' ] >> >> tmp[Symbol.weakValues] = true; >> >> This is what I was saying :> I understand that you need both a >> reference to the WeakMap and the object you're using as a "weak key" >> but I think it could be iterable if the weak references have not been >> broken yet - if the objects in that WeakMap have not been collected >> yet. I would not want "permanently" strong references with a Map. >> > > > > -- > www.soundstep.com > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss >
_______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
