Why body-parser only works in app.js?

Question

Node.js

I figured it was my mistake.
The connection to the database must be moved to a separate file and connected in the file with the request.
The bodyparser has nothing to do with it, the request to the database did not pass.
----------------------------
Hello.
The situation is this, I include a bodyparser in app.js

const express = require('express')
const mongoose = require('mongoose')
const pg = require('pg')
const bodyParser = require('body-parser')
const authRoutes = require('./routes/auth')
const analyticsRoutes = require('./routes/analytics')
const categoryRoutes = require('./routes/category')
const orderRoutes = require('./routes/order')
const positionRoutes = require('./routes/position')
const keys = require('./lib/config/keys')
const app = express()

const pgdb = new pg.Pool(keys.pgPool)
pgdb.connect()
  .then(() => console.log('PG Connected'))
  .catch(error => console.log(error))

app.use(require('morgan')('dev'))
app.use(bodyParser.urlencoded({extended: true}))
app.use(bodyParser.json())
app.use(require('cors')())

app.use('/api/auth', authRoutes)

module.exports = app

and I try to write a post request, which I also write in app.js

app.post('/register', async (req, res) => {
    const obj = req.body
    const queryReg = 'INSERT INTO public.users(email, password) VALUES ($1, $2)'
    await pgdb.query(queryReg, [obj.email, obj.password])
    res.send('ok')
  }

The request is processed. But I want to put routers and controllers in separate files.
I create a folder of routes, I include the route in app.js the content of the route

const authRoutes = require('./routes/auth')

const express = require('express')
const controller = require('../controllers/auth')
const router = express.Router()
 
 
router.post('/login', controller.login)
router.post('/register', controller.register)
 
module.exports = router

for the test in the controller I prescribe res, I see the result, the route works. I register a request and it does not work, it does not parse the json object that I pass to it, but the same object parses the contents of the controller
along the route from app.js

module.exports.register = async (req, res) => {
    const obj = req.body
    const queryReg = 'INSERT INTO public.users(email, password) VALUES ($1, $2)'
    await pgdb.query(queryReg, [obj.email, obj.password])
    res.send('ok')
  }

Why does the bodyparser only parse in the main file?