First Firebase integration - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize Firebase in your app.

Firebase

import { initializeApp } from 'firebase/app';

const firebaseConfig = {
  apiKey: "YOUR_API_KEY",
  authDomain: "YOUR_AUTH_DOMAIN",
  projectId: "YOUR_PROJECT_ID",
  storageBucket: "YOUR_STORAGE_BUCKET",
  messagingSenderId: "YOUR_MESSAGING_SENDER_ID",
  appId: "YOUR_APP_ID"
};

const app = [1](firebaseConfig);

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

AlaunchApp

BstartApp

CinitializeApp

DcreateApp

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name that does not exist in Firebase SDK.

Forgetting to pass the configuration object.

The initializeApp function sets up Firebase with your configuration.

2fill in blank

medium

Complete the code to import Firestore from Firebase.

Firebase

import { [1] } from 'firebase/firestore';

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

AgetFirestore

Bfirestore

CinitializeFirestore

DcreateFirestore

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'firestore' which is not a function.

Using 'initializeFirestore' which is less common for basic usage.

getFirestore is the correct function to import Firestore service.

3fill in blank

hard

Fix the error in the code to get Firestore instance.

Firebase

const db = getFirestore([1]);

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

AfirebaseConfig

BfirebaseApp

Cconfig

Dapp

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the config object instead of the app instance.

Passing an undefined variable.

The getFirestore function requires the Firebase app instance, which is stored in app.

4fill in blank

hard

Fill both blanks to add a document to Firestore.

Firebase

import { collection, [1] } from 'firebase/firestore';

const docRef = await [2](collection(db, 'users'), { name: 'Alice', age: 30 });

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

AaddDoc

BsetDoc

CaddDocument

DcreateDoc

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'setDoc' which requires a document reference, not a collection.

Using non-existent functions like 'addDocument' or 'createDoc'.

addDoc is the correct function to add a new document to a collection.

5fill in blank

hard

Fill all three blanks to query Firestore documents with a condition.

Firebase

import { collection, query, where, getDocs } from 'firebase/firestore';

const q = [1](collection(db, 'users'), [2]('age', [3], 25));
const querySnapshot = await getDocs(q);

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

Aquery

Bwhere

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong operators like '<' when the condition is 'greater than'.

Mixing up the order of functions.

Use query to create a query, where to add a condition, and '>' to filter ages greater than 25.

Practice

1. What is the first step to use Firebase services in your app?

easy

A. Initialize Firebase with your project configuration

B. Write data to the database

C. Create a user account

D. Deploy your app to the web

Solution

1. Step 1: Understand Firebase setup process

   Firebase services require initialization with your project details before use. Initializing Firebase with your config is the essential first step to enable services.

2. Final Answer:

   Initialize Firebase with your project configuration -> Option A

3. Quick Check:

   Firebase setup starts with initialization [OK]

Hint: Always start by initializing Firebase with your config [OK]

Common Mistakes:

• Trying to use services before initialization
• Skipping config setup
• Assuming Firebase works without project details

2. Which of the following is the correct way to initialize Firebase in JavaScript?

easy

A. firebase.configApp(config);

B. firebase.startApp(config);

C. firebase.initializeApp(config);

D. firebase.launchApp(config);

Solution

1. Step 1: Recall Firebase initialization syntax

   The official method to start Firebase is initializeApp with the config object. Only initializeApp is the correct Firebase method; others are invalid.

2. Final Answer:

   firebase.initializeApp(config); -> Option C

3. Quick Check:

   Use initializeApp to start Firebase [OK]

Hint: Remember: initializeApp starts Firebase, not startApp or others [OK]

Common Mistakes:

• Using incorrect method names
• Forgetting parentheses after method
• Passing wrong argument types

3. Given this code snippet:

const config = { apiKey: "abc123", authDomain: "myapp.firebaseapp.com" };
firebase.initializeApp(config);
console.log(firebase.apps.length);

What will be printed to the console?

medium

A. 0

B. Error

C. undefined

D. 1

Solution

1. Step 1: Understand firebase.apps array

   After initialization, firebase.apps contains all initialized app instances. Since initializeApp was called once, firebase.apps.length is 1.

2. Final Answer:

   1 -> Option D

3. Quick Check:

   One initialized app means length is 1 [OK]

Hint: firebase.apps.length shows how many apps are initialized [OK]

Common Mistakes:

• Assuming length is 0 before usage
• Expecting undefined instead of number
• Confusing apps array with config object

4. You wrote this code but get an error:

firebase.initializeApp();

What is the likely cause?

medium

A. Missing configuration object in initializeApp call

B. firebase library not imported

C. Calling initializeApp twice

D. Using wrong method name

Solution

1. Step 1: Check initializeApp requirements

   initializeApp requires a config object with project details. Calling initializeApp without config causes an error due to missing parameters.

2. Final Answer:

   Missing configuration object in initializeApp call -> Option A

3. Quick Check:

   initializeApp needs config object [OK]

Hint: Always pass config object to initializeApp [OK]

Common Mistakes:

• Forgetting to pass config
• Assuming default config is used
• Ignoring error messages about missing params

5. You want to integrate Firebase Authentication and Firestore in your app. Which is the correct sequence after importing Firebase?

hard

A. Initialize Firebase with config, then deploy app before using services

B. Initialize Firebase with config, then get Auth and Firestore instances

C. Get Auth and Firestore instances, then initialize Firebase

D. Deploy app first, then initialize Firebase and get services

Solution

1. Step 1: Initialization before service usage

   Firebase must be initialized with config before accessing any services like Auth or Firestore. After initialization, you can get instances of Auth and Firestore to use them in your app.

2. Final Answer:

   Initialize Firebase with config, then get Auth and Firestore instances -> Option B

3. Quick Check:

   Initialize first, then get services [OK]

Hint: Always initialize Firebase before accessing services [OK]

Common Mistakes:

• Trying to get services before initialization
• Deploying app before setup
• Confusing order of operations