Javascript, check backend when starting server

This might be a dumb question and not what you really want to do.
But in my Javascript Projects which use a backend most of them i run Nodemon when starting development. And yes if something happens I would see it there even before I commit.

Still I would just want to see that the server.js runs flawlessly in my Ci.

So my question is simply using nodemon/node how do I go about use them in CircleCi.
If I do like I do now just having “start”: “nodemon server.js” or “start”: “node server.js” my server will run endlessly and I won’t get any result. Doesn’t matter if I have any error or it works out ok. It just runs until I force stop it.

This is my example URL:

There is 2 possible errors there I would like to catch somehow.