“TypeError: db._checkNotDeleted is not a function” when creating a db Ref on Firebase

I’m working on a web app in html (and vanilla JS) that uses firebase for checking and updating values on a Realtime Database, I keep getting a lot of errors but still can’t figure out what I’m getting wrong. I’m sorry I’m new to JS and firebase.

Relevant html code (table inside form):

<form method="post" id="frmContact">
  <table style="width:50%">
  <tr>
    <th></th>
    <th></th>
  </tr>
  <tr>
    <td><input type="text" id="cedula" name="cedula" placeholder="Cédula (tuya)" size="25" type="number" minlength="4" maxlength="10" required><br></td>
    <td><input type="text" id="nv" name="nv" placeholder="#v" size="2" type="number" minlength="1" maxlength="1" required></td>
 </tr>
 <tr>
   <td><input type="text" id="telefono" name="telefono" placeholder="Teléfono de tu conductor" size="25" type="number" minlength="10" maxlength="10" required><br></td>
   <td></td>
 </tr>
 <tr>
   <td><input type="submit" value="Envíar" name="submit"></td>
   <td></td>
 </tr>
 </table>
</form>     

JS after body ends:

import {initializeApp} from "https://www.gstatic.com/firebasejs/9.12.1/firebase-app.js";
const firebaseConfig = {
    apiKey: ...,
    authDomain: ...,
    databaseURL: ...,
    projectId: ...,
    storageBucket: ...,
    messagingSenderId: ...,
    appId: ...
};

const app = initializeApp(firebaseConfig);

import {getDatabase,ref,set,get,child} from "https://www.gstatic.com/firebasejs/9.12.1/firebase-database.js";

const dbRef = ref(getDatabase); // LINE 509 (ERROR)


document.getElementById('frmContact').addEventListener('submit', function(e) {

    let v = ''.concat(document.getElementById('cedula').value, document.getElementById('nv').value)
    let p = ''.concat(document.getElementById('telefono').value)

    if (child(dbRef,'vouchers/' + v) == '1' && child(dbRef,'phoneNumber/' + p) != null) {
        set(ref(db, 'vouchers/' + v), '0');
        set(ref(db, 'phoneNumber/' + p, child(dbRef,'phoneNumber/' + p) + 1));
        window.alert("Felicidades, tu viaje ha sido pagado con éxito a " + document.getElementById('telefono'));
        
    } else if (child(dbRef,'vouchers/' + v) == '0') {
        window.alert("Este voucher promocional ya fue redimido");
    } else if (child(dbRef,'vouchers/' + v) == '1') {
        window.alert("Este teléfono no está asociado a ningún conductor");
    } else {
        window.alert("Este voucher promocional no es válido");
    };

    document.getElementById('frmContact').reset();

});

The database looks like this:

{
  "phoneNumber": {
    "0123456789": "0",
    "9876543210": "0",
    
  },
  "vouchers": {
    "00000000001": "1",
    "00000000002": "1",
    "00000000003": "1",
    "00000000004": "1",
    "00000000005": "1",
    "00000000006": "1",
    "00000000011": "1",
    "00000000012": "1",
    "00000000013": "1",
    "00000000014": "1",
    "00000000015": "1",
    "00000000016": "1"
  }
}

I’ve tried changing

import {getDatabase,ref,set,get,child} from "https://www.gstatic.com/firebasejs/9.12.1/firebase-database.js";


const dbRef = ref(getDatabase);

to

import {getDatabase,ref as _ref,set,get,child} from "https://www.gstatic.com/firebasejs/9.12.1/firebase-database.js";
const dbRef = _ref(getDatabase);

I simply want to verify with the database that the ‘voucher’ (cedula + #v) hasn’t been used yet (it’s associated value is 1), that the ‘phoneNumber’ (Telefono del conductor) exists, and if so change ‘voucher’ value to 0 and add one to the value associated with ‘phoneNumber’.

Answer

The ref() function takes an instance of Database as parameter and not the getDatabase function itself.

const app = initializeApp(firebaseConfig);
const db = getDatabase();

const dbRef = ref(db, "path/to/node");

Also, the child() function doesn’t actually fetch the data from Firebase server. You must use get() function to get the value. Try refactoring the code as shown below:

document.getElementById('frmContact').addEventListener('submit', async function(e) {
  let v = ''.concat(document.getElementById('cedula').value, document.getElementById('nv').value)
  let p = ''.concat(document.getElementById('telefono').value)

  console.log('v:', v)
  console.log('p:', p)

  const voucherVal = (await get(ref(db, 'vouchers/' + v))).val();
  const phoneVal = (await get(ref(db, 'phoneNumber/' + p))).val();

  console.log('voucherVal:', voucherVal);
  console.log('phoneVal:', phoneVal);

  if (voucherVal == '1' && phoneVal != null) {
    await set(ref(db, 'vouchers/' + v), '0');
    await set(ref(db, 'phoneNumber/' + p, phoneVal + 1));
    window.alert("Felicidades, tu viaje ha sido pagado con éxito a " + document.getElementById('telefono'));
  } else if (voucherVal == '0') {
    window.alert("Este voucher promocional ya fue redimido");
  } else if (voucherVal == '1') {
    window.alert("Este teléfono no está asociado a ningún conductor");
  } else {
    window.alert("Este voucher promocional no es válido");
  };

  document.getElementById('frmContact').reset();
});

Checkout the documentation for more information.