Why o.prototype.isPrototypeof is not a function, my javascript throws an exception

Question

I tried a small code piece:

function o(){};
var Derived = function () {}
Derived.prototype = o;
var o2 = new Derived();
console.log(o.prototype.isPrototypeof(o2));

The last line throws an exception, saying that:

console.log(o.prototype.isPrototypeof(o2));
                    ^
TypeError: o.prototype.isPrototypeof is not a function

This is weird to me, why o doesn't have prototype property? when defining a function/new object, does the name bind to a prototype property automatically?

Answer 1

You can usually depend on Javascript methods and functions being camel-cased, and this is no exception.

The method is .isPrototypeOf() .