Cannot understand the Subject of this sentence?

Question

My problem is to know who is the Subject of setting and it the following sentence:

When it is invoked, our new function simply invokes the original function that was passed in, setting the original value as this. It also passes through the arguments.

Source: https://yehudakatz.com/2011/08/11/understanding-javascript-function-invocation-and-this/, section: Using Function.prototype.bind.

1. Does the ", setting ..." expanded to ", and the new function setting" or ", the original function setting"?
2. Does the "It also passes ..." expanded to "the original function also passes" or "the new function also passes"?

Answer 1

Here “setting the original value as this” is a participle phrase modifying “our new function”. I'm not entirely sure this is good style, but it's something I've seen (and written) frequently in program documentation.

Here, the participle phrase describes something the function is doing during the main action of the sentence. So, while the function “invokes the original function” it is also “setting the original value as this”.

As for “It” in the second sentence, it's also referring to “our new function”.