Email/password signup in Firebase - Mini Project: Build & Apply

Email/password signup

📖 Scenario: You are building a simple web app that allows users to create an account using their email and password. This is a common feature in many websites and apps where users need to sign up to access personalized content.

🎯 Goal: Create a Firebase email/password signup flow that registers a new user with their email and password.

📋 What You'll Learn

Initialize Firebase app with configuration

Create variables for user email and password

Use Firebase Authentication to create a new user with email and password

Handle success and error cases properly

💡 Why This Matters

🌍 Real World

Email/password signup is a fundamental feature for many web and mobile apps to allow users to create accounts securely.

💼 Career

Understanding Firebase Authentication signup flows is essential for cloud developers building user management features in modern applications.

1

Initialize Firebase app

Write the code to initialize Firebase using the given configuration object called firebaseConfig. Create a variable called app that calls initializeApp(firebaseConfig) from the Firebase SDK.

Firebase

// Your code here to initialize Firebase app

Hint

Use initializeApp(firebaseConfig) from the Firebase SDK to start your app.

2

Create email and password variables

Create two variables called email and password and assign them the exact string values "[e-mail]" and "securePass123" respectively.

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 = initializeApp(firebaseConfig);

// Create variables email and password with exact values
// Your code here

Hint

Use const email = "[e-mail]"; and const password = "securePass123";.

3

Use Firebase Authentication to create user

Import getAuth and createUserWithEmailAndPassword from firebase/auth. Create a variable called auth by calling getAuth(app). Then write code to call createUserWithEmailAndPassword(auth, email, password).

Firebase

import { initializeApp } from 'firebase/app';
import { getAuth, createUserWithEmailAndPassword } from 'firebase/auth';

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 = initializeApp(firebaseConfig);

const email = "[e-mail]";
const password = "securePass123";

// Create auth variable and call createUserWithEmailAndPassword
// Your code here

Hint

Use const auth = getAuth(app); and then call createUserWithEmailAndPassword(auth, email, password);.

4

Handle signup success and errors

Add .then() and .catch() to the createUserWithEmailAndPassword call. In .then(), receive userCredential and create a variable user from userCredential.user. In .catch(), receive error and create variables errorCode and errorMessage from error.code and error.message respectively.

Firebase

import { initializeApp } from 'firebase/app';
import { getAuth, createUserWithEmailAndPassword } from 'firebase/auth';

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 = initializeApp(firebaseConfig);

const email = "[e-mail]";
const password = "securePass123";

const auth = getAuth(app);

// Add then and catch to handle success and errors
// Your code here

Hint

Use .then((userCredential) => { const user = userCredential.user; }) and .catch((error) => { const errorCode = error.code; const errorMessage = error.message; }).

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