I am asking why, to get an object's prototype, it has been implemented getPrototypeOf as a static method on Object's constructor rather than in its prototype?
Is there any reason for JS creators not to do
Object.prototype.getPrototypeOf = function() { return Object.getPrototypeOf(this); };
(which I could do myself but I know it is not good to extend JS standard objects' prototypes)?
[EDIT] Look, I am not proposing to add getPrototypeOf to Object.prototype, just curious about it wasn't done. I believe it was because of possible malfunctioning in specific cases
Putting anything into Object's prototype means adding it to all the objects ever created in all existing and future JS code on earth. Consequences would be very unpredictable. These extra 7 chars - not too high price to pay for stability.
Well, this method implemented in Object.prototype would be called just getPrototype (as far as getPrototypeOf with no arguments looks a bit strange). It is a very common name and indeed someone already has such method in one of his objects with a totally different meaning. Okay, adding global getPrototype won't break his existing code, but one day I will try to call hisObj.getPrototype assuming the new meaning, and I will get something wrong.
By the way, the isPrototypeOf method added in 3rd edition of ES is 12 years older than getPrototypeOf defined by ES 5.1.