axios making an empty request then the correct request - node.js

Question

When i try to make a request to my server the client send two requests, the first with an empty body, and the second with the correct body
this is my server file
const express = require('express');
const app = express();
const server = require('http').createServer(app);
const io = require('socket.io')(server);
const cors = require('cors');
const bodyParser = require('body-parser');
const authMiddleware = require('./app/middlewares/auth.middleware');
const db = require('./config/db');
app.use(authMiddleware);
app.use(cors({ origin: '*' }));
app.use(bodyParser.json());
db.then(res => {
require('./app/routes')(app);
});
server.listen(3210, () => {
console.log('\x1b[0m', 'Backend escutando e enviando na porta 3210');
});
this is the route file
const userController = require('../controllers/user.controller');
module.exports = app => {
app.post('/sign-up', async (req, res) => {
try {
const signUpData = await userController.signUp(req.body);
res.status(200).json(signUpData.user);
} catch (error) {
console.log(error);
res.status(400).json(error);
}
});
app.post('/sign-in', async (req, res) => {
try {
const signInData = await userController.signIn(req.body);
res.header('x-auth-token', signInData.token);
res.status(200).json(signInData);
} catch (error) {
console.log(error);
res.status(400).json(error);
}
});
};
here is my axios configuration on my react project
import axios from 'axios';
export const apiUrl = 'http://localhost:3210';
export const api = axios.create({
baseURL: apiUrl,
headers: {
common: {
'Content-Type': 'application/json'
}
}
});
the function where i do the request
export const signIn = data => {
return api
.post(`/sign-in`, data)
.then(res => {
console.log(res);
})
.catch(err => {
console.log(err);
});
};
This error only occours when the request is made via client, when i
use postman everything works fine