Use the following for being able to safely get body content from HTTP requests, set the view engine (change to your liking), and displaying static content

app.js

// create an express app (import express first)
const app = express();

// tell app to use bodyParser, I believe this still needs to be imported but it's installed with express last I checked
// bodyParser will help keep your incoming http POST body clean
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: false}));

// set the view engine to be pug ONLY if you want a view engine
// if you're displaying static content in vue.js or React, you can just let it be HTML
// change pug to others like `jade`, `htmling`, etc.
app.set('view engine', 'pug');
app.set('views', './public');

// this will allow you to serve any static files
// I've separated my css and js but feel free to structures yours however you like
app.use("/styles", express.static(__dirname + '/styles'));
app.use("/js", express.static(__dirname + '/js'));