Migrating from Realtime Database to Firestore in Firebase - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize Firestore in your Firebase project.

Firebase

const db = firebase.[1]();

Drag options to blanks, or click blank then click option'

Afirestore

Bdatabase

Cstorage

Dauth

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'database' instead of 'firestore' will initialize Realtime Database, not Firestore.

Using 'storage' or 'auth' are unrelated services.

To use Firestore, you call firebase.firestore() to get the Firestore instance.

2fill in blank

medium

Complete the code to add a new document to a Firestore collection named 'users'.

Firebase

db.collection('users').[1]({ name: 'Alice', age: 30 });

Drag options to blanks, or click blank then click option'

Aget

Bset

Cupdate

Dadd

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'set' requires a document reference, not a collection.

Using 'update' only modifies existing documents.

Using 'get' retrieves data, not adds it.

The add method adds a new document with an auto-generated ID to the collection.

3fill in blank

hard

Fix the error in the Firestore query to get documents where age is greater than 25.

Firebase

db.collection('users').where('age', '[1]', 25).get();

Drag options to blanks, or click blank then click option'

A>

B<=

C=

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' will only find users exactly 25 years old.

Using '<=' or '!=' will not match the requirement.

The operator '>' is used to filter documents where the field is greater than the given value.

4fill in blank

hard

Fill both blanks to update a user's age and merge the data without overwriting the entire document.

Firebase

db.collection('users').doc('user123').[1]({ age: 31 }, { [2]: true });

Drag options to blanks, or click blank then click option'

Aset

Bupdate

Cmerge

Doverwrite

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'update' alone works but does not accept merge options.

Using 'overwrite' is not a Firestore method.

Using 'merge' alone is not a method.

Using set with { merge: true } updates fields without replacing the whole document.

5fill in blank

hard

Fill all three blanks to migrate a Realtime Database listener to Firestore snapshot listener.

Firebase

db.collection('users').[1]((snapshot) => {
  snapshot.docs.forEach(doc => {
    console.log(doc.[2](), doc.[3]);
  });
});

Drag options to blanks, or click blank then click option'

AonSnapshot

Bdata

Cid

Dget

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'get' instead of 'onSnapshot' will not listen for realtime changes.

Accessing document data as a property instead of calling data() causes errors.

Using 'data' as a property instead of a method.

onSnapshot listens for realtime updates. doc.data() gets document data, and doc.id gets the document ID.