What is the working principle of LESS? How is the output CSS produced?

Question

JavaScript

How does the LESS compiler work?
Ok, Angular searches the tree for directives, and that's how it works. But LESS?
I connect LESS as a library, how does all this happen, because JS does not work with files, and there is no node there?
Thank you, and Happy New Year!

Answer 1

XMLHttpRequest is the answer to everything... we send a request, in response we get the text from the file - we parse it, we mold it from this CSS - we insert it into the head in the style tag