1. Dealing with post request to get req.body

app.use(express.json());
app.use(express.urlencoded({extended:false}));

//diff...
//express.json() is a body parser for post request except html post form 
//and express.urlencoded({extended: false}) is a body parser for html post form

What are express.json() and express.urlencoded()?

[Node.js] body-parser가 뭐지?

1. Query string & params

   Express.js 에서 Route parameters, Query string 받기