[node.js] Node - how to run app.js?

Just adding this. In your package.json, if your "main": "index.js" is correctly set. Just use node .

{
  "name": "app",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
     ...
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
     ...
  },
  "devDependencies": {
    ...
  }
}