Kevin: Node.prototype.toString is never invoked when you do Object.prototype.toString.call(HTMLElement.prototype)
I understand that no one has complained. Browser differ in this area today so applications have to be careful of they ever try to get the [[Class]] of something. On Mon, May 13, 2013 at 5:12 PM, Kevin Reid <[email protected]> wrote: > On Mon, May 13, 2013 at 2:01 PM, Allen Wirfs-Brock > <[email protected]>wrote: > >> On May 13, 2013, at 1:50 PM, Erik Arvidsson wrote: >> >> The way that WebIDL require Object.prototype.toString to return "[object >> TypePrototype]" for the interface prototype object and "[object Type]" for >> the instances seems to imply that every instance needs to have an own >> @@toStringTag. >> >> http://people.mozilla.org/~jorendorff/es6-draft.html#sec-15.2.4.2 >> http://dev.w3.org/2006/webapi/WebIDL/#es-environment >> >> If an instance does not have its own @@toStringTag, >> Object.prototype.toString will read through to the [[Prototype]] which >> would return the wrong string. >> >> Well, toString just does a [[Get]] for @@toStringTag. You are perfectly >> free to implement it as a get accessor that takes into account whether the >> this value is an instance or a prototype object. Not sure whether the >> complexity is really worth it in most cases. I considered building >> something like that into Object.prototype.toString but it seemed hard to >> justify and there was no (ES) legacy reason for doing so. >> >> The preferred way to over-ride toString should be via a toString method, >> not via @@toStringTag. >> > > FWIW, oddball implementor's experience: > > In Caja's emulated DOM type hierarchy, Node.prototype.toString is an > ordinary method which searches the prototype chain for the appropriate > type-name, including distinguishing prototypes. This seems to work fine > insofar as it gives the answers I want it to give and nobody's ever > complained, and I think it's identical in abilities and effects to your > proposal of an @@toStringTag accessor. > -- erik
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