If you don't know how to use `let` vs `const` properly, you will never make it a FAANG (the code you just posted is wrong). I've been following this thread and it's very clear that you severely lack fundamental understandings of JavaScript. You have displayed many many incorrect assumptions throughout the post.

I also see that you've edited your original post. With 10 years of experience, I would expect far more from you and I would never consider you a senior engineer. You will not survive at Amazon.

Please read this article to help you prepare better: https://davidshariff.com/blog/preparing-for-a-front-end-web-development-interview-in-2017/