This code was written by taken the Radu lessons. I was just practicing JS and found Radu's Youtube channel and found it very interesting. No, it's wonderful! Along as this code was actualy written intead of cloned, the original code from his work is in https://github.com/gniziemazity/virtual-world.git. In the readme section of Radu's repo is the links to the two phases of this course.
Keep in mind that this code will either not be maintained nor extended without the knowledge of Radu.
His personal website is https://radufromfinland.com
And more important! Coding with Radu!