When Closure get external variable's value?

[Huayang Xia]

I'm confused. What is the definition of closure.

I'm not sure if it's correct, I get the definition from wikipedia:

"A closure typically comes about when one function is declared entirely
within the body of another, and the inner function refers to local
variables of the outer function. At runtime, when the outer function
executes, a closure is formed. It consists of the inner function's code
and references to any variables in the outer function's scope that the
closure needs."

I agree it is not declaration, it's definition. However it's closure
based on the above definition. It uses free variable. Or you mean it's
a closure only when the outer function returns it and be exposed to
external world?

The code snippet was just for test purpose. My question was how the
free variable inside inner function (the closure) binds with object.
That was answered by Fredrik perfectly.