In the following paragaraph, the author is trying to create a stealth function that pretends to
be a native function. But he finds one problem: the stealth function has "prototype."
In other words, if the function has "prototype", then it's a fake function.

---

Is it perfect? not yet. The one problem I couldn’t find a solution for is the “prototype” property.

i.e., the native toString doesn’t have one:

'prototype' in Function.prototype.toString;
false

Where’s the tampered:

'prototype' in Function.prototype.toString;
true

You might think “oh, just use the delete operator“, but it won’t work since it’s a non-configurable property:

delete Function.prototype.toString.prototype;
false

'prototype' in Function.prototype.toString;
true

Let me know if you can find a solution to this one!

function isNative(fn){
	return !("prototype" in fn);
};