Email/password signup in Firebase - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize Firebase Authentication.

Firebase

const auth = [1](app);

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

AsignInWithEmailAndPassword

BcreateUserWithEmailAndPassword

CinitializeApp

DgetAuth

Attempts:

3 left

💡 Hint

Common Mistakes

Using user creation or sign-in functions instead of initializing auth.

Trying to initialize Firebase app instead of auth.

The getAuth() function initializes the Firebase Authentication service.

2fill in blank

medium

Complete the code to create a new user with email and password.

Firebase

firebase.auth().[1](email, password).then(userCredential => { console.log('User created'); });

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

AcreateUserWithEmailAndPassword

BsignInWithEmailAndPassword

CsendPasswordResetEmail

DsignOut

Attempts:

3 left

💡 Hint

Common Mistakes

Using sign-in method instead of user creation.

Trying to reset password instead of creating user.

The createUserWithEmailAndPassword method creates a new user account with the given email and password.

3fill in blank

hard

Fix the error in the code to handle signup errors correctly.

Firebase

firebase.auth().createUserWithEmailAndPassword(email, password).catch(error => { console.error([1]); });

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

Aerror.message

Berror

Cerror.code

Derror.details

Attempts:

3 left

💡 Hint

Common Mistakes

Logging the whole error object instead of the message.

Using a non-existent property like error.details.

The error.message property contains a readable description of the error, which is best for logging.

4fill in blank

hard

Fill both blanks to import and initialize Firebase app correctly.

Firebase

import { [1] } from 'firebase/app';
const app = [2](firebaseConfig);

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

AinitializeApp

BgetAuth

DfirebaseConfig

Attempts:

3 left

💡 Hint

Common Mistakes

Importing getAuth instead of initializeApp.

Using firebaseConfig as a function.

You import initializeApp and then call it with your config to start Firebase.

5fill in blank

hard

Fill all three blanks to sign up a user and handle success and error.

Firebase

firebase.auth().[1](email, password)
  .then(userCredential => {
    console.log('User ID:', userCredential.user.[2]);
  })
  .catch(error => {
    console.error('Error:', error.[3]);
  });

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

AcreateUserWithEmailAndPassword

Buid

Cmessage

DsignInWithEmailAndPassword

Attempts:

3 left

💡 Hint

Common Mistakes

Using sign-in method instead of create user.

Logging error code instead of message.

Accessing wrong user property.

Use createUserWithEmailAndPassword to sign up, access the user's uid for ID, and log the error message on failure.

Practice

1. What does the Firebase method createUserWithEmailAndPassword do?

easy

A. It registers a new user with an email and password.

B. It logs in an existing user with email and password.

C. It deletes a user account from Firebase.

D. It updates the user's email address.

Solution

1. Step 1: Understand the method purpose

   The method createUserWithEmailAndPassword is designed to create a new user account using email and password credentials.

2. Step 2: Differentiate from other user methods

   Logging in uses a different method, and deleting or updating users require other Firebase functions.

3. Final Answer:

   It registers a new user with an email and password. -> Option A

4. Quick Check:

   createUserWithEmailAndPassword = register user [OK]

Hint: Remember 'create' means new user signup, not login [OK]

Common Mistakes:

• Confusing signup with login method
• Thinking it updates user info
• Assuming it deletes users

2. Which of the following is the correct syntax to create a user with email and password in Firebase (JavaScript)?

easy

A. firebase.auth().signUpWithEmail(email, password)

B. firebase.createUser(email, password)

C. firebase.auth().createUserWithEmailAndPassword(email, password)

D. firebase.auth().registerUser(email, password)

Solution

1. Step 1: Recall Firebase Auth syntax

   The correct method to create a user is called on the auth object: createUserWithEmailAndPassword(email, password).

2. Step 2: Verify method names

   Other options use incorrect method names that do not exist in Firebase Auth API.

3. Final Answer:

   firebase.auth().createUserWithEmailAndPassword(email, password) -> Option C

4. Quick Check:

   Correct Firebase signup syntax = firebase.auth().createUserWithEmailAndPassword(email, password) [OK]

Hint: Look for 'auth' and exact method name [OK]

Common Mistakes:

• Using non-existent method names
• Omitting 'auth()' before method
• Mixing signup and login method names

3. What will be the output if the following code runs successfully?

firebase.auth().createUserWithEmailAndPassword('[e-mail]', 'pass123')
  .then(userCredential => console.log(userCredential.user.email))
  .catch(error => console.log(error.message));

medium

A. pass123

B. [e-mail]

C. undefined

D. Error message printed

Solution

1. Step 1: Understand promise resolution

   On success, then receives a userCredential object containing the user info.

2. Step 2: Access user email

   The code logs userCredential.user.email, which is the email used to create the account.

3. Final Answer:

   [e-mail] -> Option B

4. Quick Check:

   Success logs user email = [e-mail] [OK]

Hint: Success logs user email property [OK]

Common Mistakes:

• Expecting password to be logged
• Confusing error catch with success
• Assuming undefined output

4. Identify the error in this Firebase signup code snippet:

firebase.auth().createUserWithEmailAndPassword(email, password)
  .then(userCredential => console.log('User created'))
  .catch(error => console.log(error));

medium

A. Missing import of Firebase Auth module

B. Incorrect method name used

C. Using console.log inside catch is invalid

D. No error handling for empty email or password

Solution

1. Step 1: Check method and syntax

   The method name and syntax are correct; console.log in catch is valid.

2. Step 2: Consider input validation

   The code does not check if email or password are empty before calling Firebase, which can cause errors.

3. Final Answer:

   No error handling for empty email or password -> Option D

4. Quick Check:

   Input validation missing = No error handling for empty email or password [OK]

Hint: Always validate inputs before signup call [OK]

Common Mistakes:

• Assuming console.log in catch is wrong
• Thinking method name is incorrect
• Ignoring input validation importance

5. You want to create a signup form that prevents users from registering with weak passwords. Which approach best applies Firebase email/password signup with password strength validation?

hard

A. Check password strength in frontend before calling createUserWithEmailAndPassword and show errors if weak.

B. Call createUserWithEmailAndPassword directly and rely on Firebase to reject weak passwords.

C. Skip password checks and allow any password; fix later in user profile settings.

D. Use Firebase Admin SDK on client to validate password strength.

Solution

1. Step 1: Understand Firebase password rules

   Firebase requires passwords to be at least 6 characters but does not enforce complex strength rules.

2. Step 2: Implement frontend validation

   To improve security, validate password strength on the client side before calling Firebase signup to give immediate feedback.

3. Step 3: Avoid insecure or incorrect methods

   Relying only on Firebase or skipping checks reduces security; Admin SDK is for backend, not client.

4. Final Answer:

   Check password strength in frontend before calling createUserWithEmailAndPassword and show errors if weak. -> Option A

5. Quick Check:

   Frontend validation + Firebase signup = Check password strength in frontend before calling createUserWithEmailAndPassword and show errors if weak. [OK]

Hint: Validate password strength before signup call [OK]

Common Mistakes:

• Relying only on Firebase for password strength
• Using Admin SDK on client side
• Ignoring password validation completely