How do you use Svelte with Firebase

Integrating Svelte with Firebase allows you to create powerful, real-time web applications with ease. Firebase provides a comprehensive suite of backend services such as real-time databases, authentication, cloud functions, and more. In this article, we’ll explore how to use Firebase with Svelte, covering topics like setting up Firebase, integrating authentication, using Firestore for real-time data, and deploying your Svelte app to Firebase Hosting.

1. Setting Up Firebase

Step 1: Create a Firebase Project

Go to the Firebase Console.
Click on “Add Project” and follow the setup wizard to create a new project.
Once the project is created, navigate to the project dashboard.

Step 2: Register Your App

In the Firebase Console, click on the “Web” icon to register a new web app.
Follow the instructions to register your app and obtain the Firebase configuration object.

Step 3: Install Firebase SDK

In your Svelte project, install the Firebase SDK:
```
npm install firebase
```

2. Creating a Svelte Project

Step 1: Set Up a New Svelte Project

Create a new Svelte project using the template:

npx degit sveltejs/template svelte-firebase
cd svelte-firebase
npm install

Step 2: Start the Development Server

Start the development server:
```
npm run dev
```
Your Svelte project is now set up and running at http://localhost:5000.

3. Integrating Firebase with Svelte

Step 1: Initialize Firebase

Create a new file src/firebase.js and initialize Firebase with your configuration:

// src/firebase.js
import firebase from 'firebase/app';
import 'firebase/auth';
import 'firebase/firestore';

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"
};

// Initialize Firebase
firebase.initializeApp(firebaseConfig);

export const auth = firebase.auth();
export const firestore = firebase.firestore();

Replace the placeholders with your Firebase project configuration values.

Step 2: Use Firebase in Svelte Components

In your Svelte components, import the Firebase services:

<!-- src/App.svelte -->
<script>
  import { auth, firestore } from './firebase';
</script>

<main>
  <h1>Welcome to Svelte with Firebase!</h1>
</main>

4. Firebase Authentication

Step 1: Implement Authentication

Create a new component src/Auth.svelte to handle user authentication:

<!-- src/Auth.svelte -->
<script>
  import { auth } from './firebase';
  import { writable } from 'svelte/store';

  let email = '';
  let password = '';
  let user = writable(null);
  let error = writable(null);

  const signUp = async () => {
    try {
      const userCredential = await auth.createUserWithEmailAndPassword(email, password);
      user.set(userCredential.user);
    } catch (err) {
      error.set(err.message);
    }
  };

  const signIn = async () => {
    try {
      const userCredential = await auth.signInWithEmailAndPassword(email, password);
      user.set(userCredential.user);
    } catch (err) {
      error.set(err.message);
    }
  };

  const signOut = async () => {
    await auth.signOut();
    user.set(null);
  };
</script>

<div>
  <h2>Authentication</h2>
  <input type="email" bind:value={email} placeholder="Email" />
  <input type="password" bind:value={password} placeholder="Password" />
  <button on:click={signUp}>Sign Up</button>
  <button on:click={signIn}>Sign In</button>
  <button on:click={signOut}>Sign Out</button>

  {#if $error}
    <p style="color: red">{$error}</p>
  {/if}

  {#if $user}
    <p>Welcome, {$user.email}</p>
  {/if}
</div>

Update App.svelte to include the Auth component:

<!-- src/App.svelte -->
<script>
  import Auth from './Auth.svelte';
</script>

<main>
  <h1>Welcome to Svelte with Firebase!</h1>
  <Auth />
</main>

Step 2: Handling Auth State

Update src/Auth.svelte to listen for authentication state changes:

<!-- src/Auth.svelte -->
<script>
  import { auth } from './firebase';
  import { writable } from 'svelte/store';

  let email = '';
  let password = '';
  let user = writable(null);
  let error = writable(null);

  auth.onAuthStateChanged(currentUser => {
    user.set(currentUser);
  });

  const signUp = async () => {
    try {
      const userCredential = await auth.createUserWithEmailAndPassword(email, password);
      user.set(userCredential.user);
    } catch (err) {
      error.set(err.message);
    }
  };

  const signIn = async () => {
    try {
      const userCredential = await auth.signInWithEmailAndPassword(email, password);
      user.set(userCredential.user);
    } catch (err) {
      error.set(err.message);
    }
  };

  const signOut = async () => {
    await auth.signOut();
    user.set(null);
  };
</script>

<div>
  <h2>Authentication</h2>
  <input type="email" bind:value={email} placeholder="Email" />
  <input type="password" bind:value={password} placeholder="Password" />
  <button on:click={signUp}>Sign Up</button>
  <button on:click={signIn}>Sign In</button>
  <button on:click={signOut}>Sign Out</button>

  {#if $error}
    <p style="color: red">{$error}</p>
  {/if}

  {#if $user}
    <p>Welcome, {$user.email}</p>
  {/if}
</div>

5. Using Firestore with Svelte

Step 1: Setting Up Firestore

Create a new component src/Firestore.svelte to handle Firestore interactions:

<!-- src/Firestore.svelte -->
<script>
  import { firestore } from './firebase';
  import { writable } from 'svelte/store';

  let message = '';
  let messages = writable([]);

  const addMessage = async () => {
    try {
      await firestore.collection('messages').add({
        text: message,
        timestamp: firebase.firestore.FieldValue.serverTimestamp()
      });
      message = '';
    } catch (err) {
      console.error('Error adding message:', err);
    }
  };

  firestore.collection('messages').orderBy('timestamp')
    .onSnapshot(snapshot => {
      const data = snapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));
      messages.set(data);
    });
</script>

<div>
  <h2>Firestore Messages</h2>
  <input type="text" bind:value={message} placeholder="Type a message..." />
  <button on:click={addMessage}>Send</button>

  <ul>
    {#each $messages as msg (msg.id)}
      <li>{msg.text}</li>
    {/each}
  </ul>
</div>

Update App.svelte to include the Firestore component:

<!-- src/App.svelte -->
<script>
  import Auth from './Auth.svelte';
  import Firestore from './Firestore.svelte';
</script>

<main>
  <h1>Welcome to Svelte with Firebase!</h1>
  <Auth />
  <Firestore />
</main>

6. Deploying Svelte App to Firebase Hosting

Step 1: Install Firebase Tools

Install the Firebase CLI:
```
npm install -g firebase-tools
```

Step 2: Initialize Firebase Hosting

Initialize Firebase in your project directory:
```
firebase init
```
Follow the prompts to set up Firebase Hosting and select your Firebase project. Choose dist as the public directory (this is where the Svelte app will be built).

Step 3: Build and Deploy

Build your Svelte app:
```
npm run build
```
Deploy to Firebase Hosting:
```
firebase deploy
```

Your Svelte app is now deployed to Firebase Hosting!

Conclusion

By combining Svelte with Firebase, you can build powerful, real-time web applications with ease. In this article, we’ve covered how to set up Firebase, integrate authentication, use Firestore for real-time data, and deploy your Svelte app to Firebase Hosting. With these tools at your disposal, you can create dynamic and responsive applications that provide a seamless user experience.

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