node-server.service

# sudo nano /etc/systemd/system/node-server.service

[Service]
WorkingDirectory=/path/to/your/repo
ExecStart=/usr/local/bin/node --expose-gc /home/pi/path/to/your/repo/server.js
Restart=always
StandardOutput=syslog
StandardError=syslog
SyslogIdentifier=nodeServer
User=root
Group=root
Environment=NODE_ENV=production

[Install]
WantedBy=multi-user.target