Node.js Data in the body not being saved - node.js

Question

All my projects were working fine before but all of sudden the content of the body is not being saved as if the body is not being parsed or something. Just to check I created this simple project of book directory but no luck.
Any help would be appreciated.
Thank you
app.js
var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var mongoose = require('mongoose');
var config = require('./config');
// import bodyParser from "body-parser";//for typscript code only, use require for js
// app.use(bodyParser.json());
// app.use(bodyParser.urlencoded({ extended: false }));
var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');
var bookRouter = require('./routes/books_routes');
const url = config.mongoURL;
const connect = mongoose.connect(url);
connect.then((DB)=>{
console.log("Connected With the MongoDB Server");
},(err)=>{next(err)})
.catch((err)=>next(err));
var app = express();
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
app.use(logger('dev'));
app.use(cookieParser());
app.use(express.json());
app.use(express.urlencoded({
extended: true
})); //Parse URL-encoded bodies
app.use(express.static(path.join(__dirname, 'public')));
app.use('/', indexRouter);
app.use('/users', usersRouter);
app.use('/books',bookRouter);
// catch 404 and forward to error handler
app.use(function(req, res, next) {
next(createError(404));
});
// error handler
app.use(function(err, req, res, next) {
// set locals, only providing error in development
res.locals.message = err.message;
res.locals.error = req.app.get('env') === 'development' ? err : {};
// render the error page
res.status(err.status || 500);
res.render('error');
});
module.exports = app;
Route File
const express = require('express');
const mongoose =require('mongoose');
const Books = require('../models/books');
const bookrouter = express.Router();
// bookrouter.use(bodyparser.json());
bookrouter.use(express.json());
bookrouter.use(express.urlencoded({
extended: true
})); //Parse URL-encoded bodies
bookrouter.route('/')
.get((req,res,next)=>{
Books.find({})
.then((books)=>{
res.statusCode = 200;
res.setHeader('content-Type','application/json');
res.json(books);
},(err)=>{next(err)})
.catch((err)=>next(err))
})
.post((req,res,next)=>{
var book = new Books({
book_name: req.body.book_name,
book_author: req.body.book_author,
book_description: req.body.book_description
})
book.save()
.then((book)=>{
Books.findById(book._id)
.then((book)=>{
res.statusCode = 200;
res.setHeader('content-type','application/json');
res.json(book);
},(err)=>next(err))
})
})
.put((req,res,next)=>{
res.send("PUT request is not supported at this API");
})
.delete((req,res,next)=>{
Books.remove({})
.then((resp)=>{
res.statusCode=200;
res.setHeader('content-type','application/json');
res.send(resp);
})
})
module.exports = bookrouter;
Model file
const mongoose = require('mongoose');
var Schema = mongoose.Schema;
var passportlocalmongoose = require('passport-local-mongoose');
var Books = new Schema({
book_name :{
type:String
},
book_author:{
type:String
},
book_description:{
type:String
}
},{
timestamps:true
})
Books.plugin(passportlocalmongoose);
module.exports = mongoose.model('Book',Books);
package.json
{
"name": "books-directory",
"version": "0.0.0",
"private": true,
"scripts": {
"start": "node ./bin/www"
},
"dependencies": {
"body-parser": "^1.19.0",
"cookie-parser": "~1.4.4",
"debug": "~2.6.9",
"express": "~4.16.1",
"http-errors": "~1.6.3",
"jade": "~1.11.0",
"mongodb": "^3.0.10",
"mongoose": "^5.1.7",
"mongoose-currency": "^0.2.0",
"morgan": "~1.9.1",
"passport": "^0.4.0",
"passport-local": "^1.0.0",
"passport-local-mongoose": "^5.0.1"
}
}