I am new to React Native. I created a Registration App connected to a local PostgreSql Database. I am using Formik for the form, after submitting the form it is recorded in the database. The app refreshes everytime I save the code. However after some refreshes, the data is duplicated in the database. I am using axios and a Rest API. Also using nodemon for the server.

Duplicated Data in the Database

POST REQUEST

    const url = 'http://192.168.254.106:5000/users';

    handleMessage(null);
    handleMessage('Successfully Signed Up!', 'SUCCESS');

    try {
      const response = await axios.post(url, credentials);
    } catch (error) {
      handleMessage('An Error Occured.');
    }

    setSubmitting(false);
  }, []);

REST API

const app = express();
const cors = require('cors');
const pool = require('./database');

//middleware
app.use(cors());
app.use(express.json());

//ROUTES

//create user

app.post('/users', async (req, res) => {
  try {
    const { fullname, email, birthdate, password } = req.body;

    const user = await pool.query(
      'INSERT INTO users(fullname, email, birthdate, password) VALUES($1, $2, $3, $4) RETURNING *',
      [fullname, email, birthdate, password],
    );
  } catch (err) {
    console.error(err.message);
  }
});

//get all users
app.get('/users', async (req, res) => {
  try {
    const allUsers = await pool.query('SELECT * FROM users');
    res.json(allUsers.rows);
  } catch (err) {
    console.error(err.message);
  }
});

//get a user

app.get('/users/:id', async (req, res) => {
  try {
    const { id } = req.params;
    const user = await pool.query('SELECT * FROM users WHERE user_id=$1', [id]);

    res.json(user.rows);
  } catch (err) {
    console.error(err.message);
  }
});

//update a user
app.put('/users/:id', async (req, res) => {
  try {
    const { id } = req.params;
    const { email } = req.body;

    const updateUser = await pool.query('UPDATE users SET email = $1 WHERE user_id=$2', [email, id]);

    res.json('Updated!');
  } catch (err) {
    console.error(err.message);
  }
});

//delete a user
app.delete('/users/:id', async (req, res) => {
  try {
    const { id } = req.params;

    const deleteUser = await pool.query('DELETE FROM users WHERE user_id=$1', [id]);

    res.json('Deleted!');
  } catch (err) {
    console.error(err.message);
  }
});

app.listen(5000, () => {
  console.log('Server is up');
});