On Wed, Oct 17, 2012 at 2:55 PM, Brendan Eich <bren...@mozilla.org> wrote:
> Tom Van Cutsem wrote: > >> 2012/10/16 Herby Vojčík <he...@mailbox.sk <mailto:he...@mailbox.sk>> >> >> >> I see two solutions: >> - add something to the freeze, seal, preventExtensions family which >> would set an object to the fail-fast [[Get]] state. >> - use a Proxy in the proto chain to trap the unknown [[Get]] and >> throw early >> >> Do you think this needs a solution at all? If yes, which option would >> you favour? >> >> >> The second option is easy to accomplish but pretty invasive since it >> requires you to inherit from a particular object. If you have an >> abstraction that already inherits from something else, you're hosed. >> >> Personally, I'm not convinced this is a big enough problem to warrant >> another "mode" for Javascript objects. >> > > This has come up in TC39, and on this list. Waldemar would like a way (not > the default) to seal a class so typo'ed member names throw: > > https://mail.mozilla.org/**pipermail/es-discuss/2012-May/**022837.html<https://mail.mozilla.org/pipermail/es-discuss/2012-May/022837.html> > > However, since then, I recall hearing Waldemar say that the private > at-name syntax in classes (for him) made the case that maximally minimal > classes hang together in ES6, without any "const class" or sealed class > option. > > I agree it's not a big enough problem to add a "mode" or anything like > that. Opt-in by class could be helpful. TypeScript has its optional member > syntax (?:) and can give warnings. It seems to me this kind of tool-time > help might be enough. As I understand it, the idea is to allow gets only after a prior set. There is a mode in Ruby that warns if you try to access an uninitialized instance variable, but people consider it annoying because it breaks common patterns (and in Ruby, unlike JavaScript, ||= is an operator, so it can skip warning in that case). I suspect that people trying to use objects that threw when trying to get uninitialized property would be extremely frustrated, and rightly so. > > > /be > > ______________________________**_________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/**listinfo/es-discuss<https://mail.mozilla.org/listinfo/es-discuss> > -- Yehuda Katz (ph) 718.877.1325
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