I'm not really sure how you're expecting to get an answer "according to TC39." One member had replied and given his suggestion. I don't think it's a good one for new APIs; I think new APIs should use arrays and not type check on sets but at processing time. I'm sure there will be many other opinions from other TC39 members.
________________________________ From: "Tab Atkins Jr." <[email protected]> Sent: Jun 9, 2017 5:02 PM To: Adam Klein Cc: es-discuss Subject: Re: Intercepting sets on array-like objects On Fri, Jun 9, 2017 at 1:57 PM, Adam Klein <[email protected]> wrote: > On Thu, Jun 8, 2017 at 11:32 AM, Tab Atkins Jr. <[email protected]> > wrote: >> Note that if we don't get some variant of this functionality, these >> APIs will instead do one of: >> >> * just using Proxies (already defined in WebIDL) > > > When you say "Proxies" here, I believe you're referring to the "indexed > properties" feature of WebIDL > (https://heycam.github.io/webidl/#idl-indexed-properties). This seems like > the right mechanism to use, from a WebIDL spec, to get the behavior you > desire. In Chromium/V8, this doesn't actually use Proxies under the hood (we > have something called "indexed property handlers", see the API at > https://cs.chromium.org/chromium/src/v8/include/v8.h?rcl=ff98ddca4a1770c2868d44f1cdfe1d4656363f30&l=5781), > but it's definitely implementable using Proxies. Correct. WebIDL's indexed getters/setters would fulfill my use-case *exactly*. If that's okay to use, per TC39 consensus, then awesome! However, in <https://github.com/heycam/webidl/issues/345#issuecomment-300734048> Anne says: > [When] we discussed those kind of approaches with TC39, they told us not > to and to just use Array. It wasn't just about [], it was also about FileList, > NodeList, etc. And the problem with those was not that they did not have > enough methods like Array, it was that they required a proxy. Thus my confusion/consternation. If this is incorrect, and indexed getters/setters are indeed fine to use in new APIs, then we can close this thread "no change" and I can go away happy. ^_^ ~TJ _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
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