what is body parser in nodejs code example

Example 1: body parser use

var express = require("express");
var app = express();
var bodyParser = require("body-parser");
app.use(bodyParser.urlencoded({extended: true}));

Example 2: body parser

var express = require('express')
  var bodyParser = require('body-parser')
  var app = express()
  // parseapplication/x-www-form-urlencoded
  app.use(bodyParser.urlencoded({ extended: false }))
  // parse application/json
  app.use(bodyParser.json()) app.use(function (req, res) {  res.setHeader('Content-Type', 'text/plain')  res.write('you posted:\n')  res.end(JSON.stringify(req.body, null, 2))})