It's not as impossible as it sounds. There are many JS engines which are extremely small compared to the big guys used in browsers. Most of them tend to grab a

It's not as impossible as it sounds. There are many JS engines which are extremely small compared to the big guys used in browsers. Most of them tend to grab a subset of the language and implement that. For example, the creators of nginx created their own specialized engine called nginScript that runs JS for their stuff https://www.nginx.com/resources/wiki/nginScript/ https://www.nginx.com/resources/wiki/nginScript/ There is even a javascript interpreter written in javascript which can be a good starting point to learn a bit how it works https://github.com/jterrace/js.js/ https://github.com/jterrace/js.js/