How to implement LRU CACHE on node.js?

Question

Node.js

Hello. My task is to implement the cache on the site. Their server is on node.js.
I can't dig up much information. And I didn't work much with the server either.

Please provide material that can help me approach this issue. I want not just to implement and forget, but to understand how it all works. Thank you.

For example, I understand that there will be some object with information on the server. But I don't really understand how to put a page in it.

If the question is too stupid, don't rush. Understanding is still not particularly in the question