What are the best ways to build Recommender System in Nodejs ?

What are the best possible way to build a recommender system with nodejs in addition with machine learning. I am working on a side project that requires a personalized products or listing based on a user preference

How would you rate(optimize) your Productivity as a Developer or as a Manager?

What is the best way to handle errors in a React/Redux application?

How to deal with FOUC(Flash of Unstyled Content) with server-side rendering using less at initial load?