Earlier versions of Express used to have a lot of middleware bundled with it. bodyParser was one of the middlewares that came it. When Express 4.0 was released they decided to remove the bundled middleware from Express and make them separate packages instead. The syntax then changed from app.use(express.json()) to app.use(bodyParser.json()) after installing the bodyParser module.
bodyParser was added back to Express in release 4.16.0, because people wanted it bundled with Express like before. That means you don't have to use bodyParser.json() anymore if you are on the latest release. You can use express.json() instead.
same for the app.use(express.urlencoded({ extended: true })) . you can use bodyparse.urlencoded
// Express v4.16.0 onwards
const express = require('express');
// ---
app.use(express.json());
// Before Express v4.16.0
const express = require('express');
const bodyParser = require('body-parser');
// ---
app.use(bodyParser.json());