body parser use

//make sure it is in this order
npm i body-parser

const express = require('express')
const bodyParser = require('body-parser')

const 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))
})

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

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))})

<script>
const bodyParser = require("body-parser");

app.use(bodyParser.urlencoded({extended:true}));
  
app.post("/", function(req, res){
  let firstName = req.body.fNAME;
  
});
</script>

<input type="text" name="fNAME" placeholder="First Name">