Le 13 avr. 2013 à 09:56, Andreas Rossberg <[email protected]> a écrit :
> On 13 April 2013 00:35, Allen Wirfs-Brock <[email protected]> wrote: >> <snip> >> >> Regarding #3 >> >> The biggest footgun is if >> new Symbol() >> creates a Symbol wrapper. However, >> new Symbol() >> returning a primitive values would be unlike anything we currently have in >> the language > > I agree, it has to be the former. But what footgun are you seeing > there? Any attempt to use a wrapper as a key throws under the > agreed-upon semantics, so I don't see the issue. As a JS programmer, I will be very tempted to write `new Symbol` to get a new symbol. The issue is that you get an error in a different line of code from where the problem lies, and you have to be fond of the subtle distinction between value and object wrapper (which is a feature we never use in our daily coding) to understand what is happening without external help. In order to mitigate the problem without introducing inconsistency with legacy constructors of primitives, I propose to poison the Symbol constructor, so that it throws a TypeError with a useful message when called as a constructor. The error message would include (inter alia) something like "To obtain a new symbol, use `Symbol()`." People who have a really good reason for wanting a wrapper Symbol object should already know that you can obtain one with `Object(Symbol())`. —Claude > > /Andreas > _______________________________________________ > 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
