Sure - you can absolutely still just write an index.html file and toss in some script tags. You can even do that with React (see https://raw.githubusercontent.com/reactjs/reactjs.org/master... ).

But, most modern JS apps have some kind of a build step, and the build tools themselves are all written in Javascript. So, you need Node to run those tools, in the same way you'd need the Python runtime to run an app written in Python, or the JRE to run an app written in Java.

Thanks, I spend all writing SQL. I have always found the prospect of setting up JavaScript development environment daunting. First and only time I tried to Node something went wrong in my setup and I spent days trying to figure out the issue. I didn't get far with both Node and JavaScript. I suppose my only issue is time.