you have a getClass mechanism but no getImplementedInterfaces one ... also
never thought about xpcomponents but at least I would speed up that
function via {}.toString.call .... rather than that double lookup per each
call :-)However, xpconnect is a very specific use case so you might decide to RegExp that if really needed or split by ( and ) Sorry could not help that much On Mon, Oct 15, 2012 at 2:59 PM, Irakli Gozalishvili <[email protected]>wrote: > Hi, > > Today I had to deal with a value type detection in JS and that reminded me > of all the pain associated with it, especially when dealing with values > that may have come across the diff compartment / frame / context. > `instanceof` is useless when dealing with objects from diff contexts, > `typeof` is also pretty limited in a sense that it can detect weather value > is array, error, map, set, etc.. not to mention it's awkwardnesses… > > Only solution that seems to work toady that is adopted by most popular JS > libraries is: > > function type(value) { > return Object.prototype.toString.call(value).split(' > ')[1].split(']')[0].toLowerCase() > } > > I don't actually know if that's supposed to work according to spec or if > it's just an implementation coincidence that happen to > work. Either way I would really welcome some standard > solution preferably via function form (so that can be polyfilled today) > to do type detection for all the built-ins and host objects. > > Aside main issue, it would be great if solution was compatible with > mozilla's xpcom components too where one object my be > queried with multiple interfaces and there for have multiple types. Also, > above hack does not works with XPCOMs as Object.prototype.toString returns > "[object XPCWrappedNative_NoHelper]", while actual toString returns > something little more useful "[xpconnect wrapped (nsISupports, nsIURI, > nsIURL)]" > > Regards > -- > Irakli Gozalishvili > Web: http://www.jeditoolkit.com/ > > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > >
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