tool: pm2: process manager for node.js

pm2 - npm

PM2 is a production process manager for Node.js applications with a built-in load balancer. It allows you to keep applications alive forever, to reload them without downtime and to facilitate common system admin tasks.

Deploying Node.js apps in Amazon Linux with pm2 | by Tanveer Hassan | Monstar Lab Bangladesh Engineering | Medium

PM2 - Home

npm install pm2 -g

pm2 start app.js

alternative tool: nodemon

nodemon.io

Running Node.js Apps in Production | if else

Nodemon tends to be best for development. 

PM2 is by far the most comprehensive and tends to be best suited for production concerns.