Problem with .json as request response in NodeJS

Question

I am developing a backend with a database in mongoDB, when defining an endpoint of type post and testing it in postman it sends me an error in the console and in postman I do not get the object that I defined as a response to the post, however if it performs the incersion correctly in the database

this is the route

/*
    /api/hospitales
*/
const { Router } = require('express');
const { check } = require('express-validator');
 
const {
    getHospitales,
    crearHospital,
    actualizarHospital,
    eliminarHospital
} = require('../controller/hospitales_controller');
 
const { validarCampos } = require('../middlewares/validarCampos_middleware');
const { validarJWT } = require('../middlewares/validarJWT_middleware');
 
const router = Router();
 
router.get('/', [], getHospitales);
 
router.post('/', [
    validarJWT,
    check('nombre', 'El nombre del hospital es necesario').not().isEmpty(),
    validarCampos
], crearHospital);
 
router.put('/:id', [], actualizarHospital);
 
router.delete('/:id', [], eliminarHospital);
 
module.exports = router;

this is the controller

    const { response } = require('express');
 
const Hospital = require('../model/hospitales_model');
 
const crearHospital = async(req, res = response) => {
 
    const uid = req.uid;
    const hospital = new Hospital({
        usuario: uid,
        ...req.body
    });
 
    try {
 
        const hospitalDB = await hospital.save();
 
        res.json({
            ok: true,
            hospital: hospitalDB
        });
 
    } catch (error) {
        console.log(error);
        res.status(500).json({
            ok: false,
            msg: 'Hable con el administrador'
        });
    }
 
};

This is the model

    const { Schema, model } = require('mongoose');
 
const HospitalSchema = Schema({
 
    nombre: {
        type: String,
        required: true
    },
    img: {
        type: String,
    },
    usuario: {
        required: true,
        type: Schema.Types.ObjectId,
        ref: 'Usuario'
    }
 
}, { collection: 'Hospitales' });
 
HospitalSchema.method('toJSON', function() {
    const { __v, ...object } = this.toObject();
    return object;
});
 
module.exports = model('Hospital', HospitalSchema);

this is the error in console

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
    at ServerResponse.setHeader (_http_outgoing.js:536:11)
    at ServerResponse.header (Z:\NODE\N_BackEndAdminPro\node_modules\express\lib\response.js:771:10)
    at ServerResponse.send (Z:\NODE\N_BackEndAdminPro\node_modules\express\lib\response.js:170:12)
    at ServerResponse.json (Z:\NODE\N_BackEndAdminPro\node_modules\express\lib\response.js:267:15)
    at crearHospital (Z:\NODE\N_BackEndAdminPro\controller\hospitales_controller.js:24:13)
    at processTicksAndRejections (internal/process/task_queues.js:93:5) {
  code: 'ERR_HTTP_HEADERS_SENT'
}
(node:14752) UnhandledPromiseRejectionWarning: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
    at ServerResponse.setHeader (_http_outgoing.js:536:11)
    at ServerResponse.header (Z:\NODE\N_BackEndAdminPro\node_modules\express\lib\response.js:771:10)
    at ServerResponse.send (Z:\NODE\N_BackEndAdminPro\node_modules\express\lib\response.js:170:12)
    at ServerResponse.json (Z:\NODE\N_BackEndAdminPro\node_modules\express\lib\response.js:267:15)
    at crearHospital (Z:\NODE\N_BackEndAdminPro\controller\hospitales_controller.js:31:32)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:14752) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:14752) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

this is the result in postman

Answer 1

Solved, Like many of the code problems that exist it was simply an extra call of the next() function in the validateJWT middleware that accompanies the request

bad code

const jwt = require('jsonwebtoken');
const validarJWT = (req, res, next) => {

//leer token
const token = req.header('x-token');

if (!token) {
    return res.status(401).json({
        ok: false,
        msg: 'No hay token en la peticion'
    });
}

try {
    const { uid } = jwt.verify(token, process.env.JWT_SECRET);
    req.uid = uid;
    next();

} catch (error) {
    return res.status(401).json({
        ok: false,
        msg: 'Token invalido'
    });
}

next();
};

rigth code

const jwt = require('jsonwebtoken');
const validarJWT = (req, res, next) => {

//leer token
const token = req.header('x-token');

if (!token) {
    return res.status(401).json({
        ok: false,
        msg: 'No hay token en la peticion'
    });
}

try {
    const { uid } = jwt.verify(token, process.env.JWT_SECRET);
    req.uid = uid;

} catch (error) {
    return res.status(401).json({
        ok: false,
        msg: 'Token invalido'
    });
}

next();
};