Verify one time password request error ?

verifyOneTimePassword.js

const admin = require('firebase-admin');

module.exports = (req, res) => {
  if (!req.body.phone || !req.body.code) {
    res.status(422).send({ error: 'must supply phone and code' });
  }

const phone = String(req.body.phone).replace(/[^\d]/g, '');
const code = parseInt(req.body.code, 10);

//validate user by referring to firebase database
admin.auth().getUser(phone)
.then(() => {
  const ref = admin.database().ref(`users/${phone}`);
  ref.on('value', snapshot => {
    ref.off();
    const currentUser = snapshot.val();

  if (currentUser.code !== code || !currentUser.codeValid) {
    return res.status(422).send({ error: 'code is not valid' });
    }

  ref.update({ codeValid: false });
  admin.auth().createCustomToken(phone)
      .then(token => res.send({ token }));
  });
})
.catch((error) => console.log(error));
};