Are anonymous functions optimized in node.js

Let’s take this stupid piece of code as an example

for (let i = 0; i < 10; i++) {
  console.log(
    (function (x) {
      if (x % 2) {
        return 'even';
      } else {
        return 'odd';
      }
    })(i)
  );
}

Basically, we have an anonymous function that is called multiple times inside a loop, or maybe inside another function.
I wonder if it is recreated on every iteration of the cycle or is it optimized somehow?
I would appreciate if you could give me a hint on how to find this kind of things on my own.
Thanks!