start node js server using cron job – CPanel

I have created API using node js and my API is live now (in production) but now I always want to open Cpanel and terminal and run command to start node js API. but now I want like I just run one-time command in terminal and it will run automatically even in my computer is shutdown. or there is another way to do it. and I google it I found some code but it’s not work
first, I try this

#!/bin/bash
ps cax | grep node > /dev/null
if [ $? -eq 0 ]; then
  echo "Process is running." >/dev/null 2>&1
else
  echo "Process is not running."
  PATH=$PATH:/usr/local/bin
  pm2 start /path/to/your/node/application
fi

then i create bat file. and just simple add node app.js then i create php file and
use this code shell_exec('npm start'); and shell_exec('sh script.sh'); but nothing work.