If you want to check the server exit non-normal in OS level, you must check the return code from the process. If the exit code is 0 then the process is finished normally. In other cases, there was an error. In node the following code is a normal exit from the process:

    process.exit();

In the server code, we exit normally on exception. So it is not possible to find out the process exit du to error. 

I add error code to the process to find out there is an exception.