NodeJS Express - TypeError: Converting circular structure to JSON

Question

Well, I'm just trying to build a simple expressJS app, but nothing seems to work, not even this code:

const express = require('express');
const bodyParser = require('body-parser');
require('dotenv').config();

const app = express();

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

/* require('./src/routes/index')(app); */

app.post('/', async (req, res) => {
    try {
        res.send(req);
    } catch(e) {
        console.log(e);
        res.send({ error: e.message });
    }
});

app.listen(process.env.PORT, () => {
    console.log(`Server initialized. Try it on http://localhost:${process.env.PORT}`);
})

Every time I try to POST this simple JSON request:

{
    "name": "namesample",
    "email": "emailsample",
    "password": "passwordsample"
}

I get this error:

{
  "error": "Converting circular structure to JSON\n    --> starting at object with constructor 'Socket'\n    |     property 'parser' -> object with constructor 'HTTPParser'\n    --- property 'socket' closes the circle"
}

and the console.log prints this:

TypeError: Converting circular structure to JSON
    --> starting at object with constructor 'Socket'
    |     property 'parser' -> object with constructor 'HTTPParser'
    --- property 'socket' closes the circle
    at JSON.stringify (<anonymous>)
    at stringify (C:\Users\joaov\Documents\Github Projects\jwt-study\node_modules\express\lib\response.js:1123:12)
    at ServerResponse.json (C:\Users\joaov\Documents\Github Projects\jwt-study\node_modules\express\lib\response.js:260:14)
    at ServerResponse.send (C:\Users\joaov\Documents\Github Projects\jwt-study\node_modules\express\lib\response.js:158:21)
    at C:\Users\joaov\Documents\Github Projects\jwt-study\app.js:14:13
    at Layer.handle [as handle_request] (C:\Users\joaov\Documents\Github Projects\jwt-study\node_modules\express\lib\router\layer.js:95:5)
    at next (C:\Users\joaov\Documents\Github Projects\jwt-study\node_modules\express\lib\router\route.js:137:13)
    at Route.dispatch (C:\Users\joaov\Documents\Github Projects\jwt-study\node_modules\express\lib\router\route.js:112:3)
    at Layer.handle [as handle_request] (C:\Users\joaov\Documents\Github Projects\jwt-study\node_modules\express\lib\router\layer.js:95:5)
    at C:\Users\joaov\Documents\Github Projects\jwt-study\node_modules\express\lib\router\index.js:281:22

Could anyone help with that please? My code isn't recognizing my request!!!

Thanks

Answer 1

if you just wanted to check your post request working or not you can change res.send(req); to res.send(req.body);

if you want to see the entire request object itself install circular-json node module and you can make changes as follows.

const express = require('express');
const bodyParser = require('body-parser');
const circularJSON = require('circular-json');
require('dotenv').config();

const app = express();

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

app.post('/', async (req, res) => {
    try {
        let json = circularJSON.stringify(req);
        res.send(json);
    } catch(e) {
        console.log(e);
        res.send({ error: e.message });
    }
});

app.listen(process.env.PORT, () => {
    console.log(`Server initialized. Try it on http://localhost:${process.env.PORT}`);
})