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": {
...
}
}