How can I run background task in node.js - node.js

Question

I saw that I could run background tasks by using nohup node index.js.
My problem is related with following source.
https://github.com/Palpasa/Node-Express-Seed.
In this source, package.json file contains nodemon and it is working when I start the server with npm start.
For now, I tried to run the server in background.
But it is crashing with following error.
[nodemon] 1.14.12
[nodemon] to restart at any time, enter `rs`
[nodemon] watching: *.*
[nodemon] starting `node app.js`
/home/tom/Documents/work/wallet/app/app.js:3
import bodyParser from 'body-parser';
^^^^^^
SyntaxError: Unexpected token import
at createScript (vm.js:80:10)
at Object.runInThisContext (vm.js:139:10)
at Module._compile (module.js:607:28)
at Object.Module._extensions..js (module.js:654:10)
at Module.load (module.js:556:32)
at tryModuleLoad (module.js:499:12)
at Function.Module._load (module.js:491:3)
at Function.Module.runMain (module.js:684:10)
at startup (bootstrap_node.js:187:16)
at bootstrap_node.js:608:3
[nodemon] app crashed - waiting for file changes before starting...
How can I run this server in background?

Answer 1

You can run several screens on your putty.
screen
Then you will have one screen.
You can now run your node instance on this screen.
This screen is alive all the time.
Type CTRL+A+D to go out of the screen.
Your node instance is now always alive even you quit putty.

Answer 2

Child Process is what you would want to use.
const { spawn } = require('child_process');
const otherScript = spawn('node', ['script-you-wanna-run.js']);
otherScript.stdout.on('data', (data) => {
console.log(`stdout: ${data}`);
});

Answer 3

You probably need to use ES-2015 babel preset to transpile the import statements. If you don't need the ES6 import specifically, just use require
var bodyParser = require("body-parser")
On another note you can try using Forever npm package. This let's you start the node server in the background
FOREVER
npm install -g forever
forever start server.js
// To run on a custom po
PORT=3000 forever start server.js

Answer 4

You cannot run nodemon in the background (i.e nohup npm start <=> nohup nodemon app.js), nodemon supposed to be used for development environment, it let you see what changes are made on files during development, if you are looking for running express app in production, Then you should use a process manager, it restarts the app automatically when it crashes, or when changes are made, read this article for more information. Here is an example using pm2 module:
Install pm2:
npm install pm2 -g
Run app:
pm2 start app.js