why we use body parser in node js 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 node

// Express/Connect top-level generic
// This example demonstrates adding a generic JSON and URL-encoded parser as a top-level middleware, which will parse the bodies of all incoming requests. 
// This is the simplest setup.

var express = require('express')
var bodyParser = require('body-parser') 
var app = express() 

// parse application/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))})

Example 3: body parser npm

var bodyParser = require('body-parser')

Example 4: body parser npm

const jsonParser = bodyParser.json()

const urlencodedParser = bodyParser.urlencoded({ extended: false })