Why can't I .call() Function.call?

Question

In Javascript, Function.call() can call Function given a this value and zero or more arguments.

Function.call its

Answer 1

Short answer: The error message is very misleading. It is the same error message you get when you do

(undefined)();

---

Longer answer:

The second .call() is being invoked with a this of Function.call.

Calling it with no parameters causes it to call this with undefined as the this value.

Therefore, you're really doing

Function.call.call(undefined)

which means you're (metaphorically) doing

undefined.call()

which is really just

undefined()

Passing nothing (or undefined) to the this parameter of Function.call.call() is essentially negating the this context of the first Function.call() (which would be just Function itself), causing .call() to be invoked on undefined.

This yields the error message that is produced: undefined is not a function.