npm install body-parser --save
const express = require('express');
const bodyParser = require('body-parser');
const app = express();
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
curl -XPOST -H "Content-Type: application/json" -d '{"username":"John","password":"Doe"}' "http://localhost:3000/login"