That is one supported use case, yes. But that isn't the only use case this supports. It can still extend to traditional private class data, too.
----- Isiah Meadows [email protected] www.isiahmeadows.com On Mon, Jul 30, 2018 at 8:04 PM, Ranando King <[email protected]> wrote: > So you're wanting the ability for a 3rd-party function to be able to store > data private to that library on an object it didn't create, and that only > that library can access? > > On Mon, Jul 30, 2018 at 6:36 PM Isiah Meadows <[email protected]> > wrote: >> >> First, my private symbols are properly *private*. The only >> "unexpected" thing that could happen is making an object larger >> memory-wise, which engines already have to be equipped to handle now >> (libraries aren't always well-behaved, and like to occasionally add >> expando properties to builtins and DOM elements). About the only thing >> most people would care about is in the debugger. >> >> Second, I had things like this in mind with supporting expando >> properties: >> https://github.com/nodejs/node/blob/ae4fde8bc883686def5badfb324236320669e8f4/lib/internal/linkedlist.js >> >> In that case, the Node.js people made it a pseudo-mixin rather than an >> actual type for performance reasons - there's fewer object allocations >> and they needed that. >> >> So I've considered the expando problem, and I disagree about it being >> a problem at all. >> >> ----- >> >> Isiah Meadows >> [email protected] >> www.isiahmeadows.com >> >> >> On Mon, Jul 30, 2018 at 6:35 PM, Waldemar Horwat <[email protected]> >> wrote: >> > On 07/29/2018 04:37 PM, Isiah Meadows wrote: >> >> >> >> BTW, I came up with an alternate proposal for privacy altogether: >> >> https://github.com/tc39/proposal-class-fields/issues/115 >> >> >> >> TL;DR: private symbols that proxies can't see and that can't be >> >> enumerated. >> > >> > >> > Aside from syntax, the main semantic difference I see between this >> > alternative and the main one is that this alternative defines private >> > fields >> > as expandos, creating opportunities for mischief by attaching them to >> > unexpected objects. Aside from privacy, one of the things the private >> > fields proposal gives you is consistency among multiple private fields >> > on >> > the same object. In the rare cases where you don't want that, you could >> > use >> > weak maps. >> > >> > Waldemar >> _______________________________________________ >> 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
