Not in ES5. Generally checking that typeof x === 'function' is a close approximation. ES5 (11.4.3) requires that both native (ie, pure actual ECMAScript objects) and host objects that implement [[Call]] produce "function" when typeof is applied to them. This is a change from ES3 that did not impose this requirement upon host object objects.
Of course it may take a while for browser implementations to respond to this change. Allen >-----Original Message----- >From: [email protected] [mailto:es-discuss- >[email protected]] On Behalf Of Garrett Smith >Sent: Friday, June 05, 2009 1:31 PM >To: es-discuss >Subject: Using IsCallable Operation? > >There seems to be a lot of controversy on how to properly check if >something should be callable. There isn't any way to determine that in >ES3. > >The internal IsCallable determines if an object has a [[Call]] property. > >Will that be available as a language feature, not internal? > >For example:- > Object.isCallable( document.images ); > >- would provide a check to internal IsCallable and return the result. > >Garrett >_______________________________________________ >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
