Deep linking basics in React Native - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the React Native Linking module.

React Native

import { [1] } from 'react-native';

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

ARouter

BNavigator

CLinking

DDeepLink

Attempts:

3 left

💡 Hint

Common Mistakes

Using Navigator or Router instead of Linking

Misspelling Linking

The Linking module is used in React Native to handle deep links.

2fill in blank

medium

Complete the code to add a listener for incoming deep links.

React Native

Linking.addEventListener('[1]', handleDeepLink);

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

Aurl

Bnavigate

CdeepLink

Dlink

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'link' or 'deepLink' instead of 'url'

Using incorrect event names

The event name for listening to deep link changes is 'url'.

3fill in blank

hard

Fix the error in this code to get the initial URL when the app starts.

React Native

const initialUrl = await Linking.[1]();

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

AgetInitialURL

BfetchURL

CopenURL

DretrieveURL

Attempts:

3 left

💡 Hint

Common Mistakes

Using openURL which opens a URL instead of getting it

Using fetchURL or retrieveURL which do not exist

The correct method to get the URL that opened the app is getInitialURL().

4fill in blank

hard

Fill both blanks to parse the path from the URL string.

React Native

const url = 'myapp://home/profile';
const path = url.[1]('://')[1].[2]('/');

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

Asplit

Bslice

CindexOf

Dsubstring

Attempts:

3 left

💡 Hint

Common Mistakes

Using slice or substring which do not split strings into arrays

Using indexOf which returns a number

First, split('://') divides the URL into scheme and path parts. Then, split('/') breaks the path into segments.

5fill in blank

hard

Fill all three blanks to handle a deep link event and extract the URL.

React Native

function handleDeepLink(event) {
  const url = event.[1];
  const route = url.[2]('://')[1].[3]('/')[0];
  console.log('Navigating to:', route);
}

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

Aurl

Bsplit

Cslice

Dsubstring

Attempts:

3 left

💡 Hint

Common Mistakes

Using event.url() as a function

Using slice or substring instead of split

Accessing wrong event property

The event object has a url property. We use split('://') to separate scheme and path, then split('/') to get the first path segment.

Practice

1. What is the main purpose of deep linking in a React Native app?

easy

A. To create animations between screens

B. To open specific screens in the app from external links

C. To improve app performance by caching data

D. To handle user authentication automatically

Solution

1. Step 1: Understand deep linking concept

   Deep linking allows apps to open specific screens directly from a URL or link.

2. Step 2: Identify the main purpose

   This helps users navigate directly to content without opening the app's home screen first.

3. Final Answer:

   To open specific screens in the app from external links -> Option B

4. Quick Check:

   Deep linking = open specific screens [OK]

Hint: Deep linking opens app screens from links [OK]

Common Mistakes:

• Confusing deep linking with app performance
• Thinking it handles animations
• Assuming it manages authentication

2. Which React Native API is used to listen for incoming deep links?

easy

A. AsyncStorage

B. Navigation

C. Linking

D. Animated

Solution

1. Step 1: Recall React Native APIs

   React Native provides the Linking API to handle URLs and deep links.

2. Step 2: Match API to deep linking

   Linking listens for URL events and opens the app screen accordingly.

3. Final Answer:

   Linking -> Option C

4. Quick Check:

   Linking API = deep link listener [OK]

Hint: Use Linking API to handle URLs [OK]

Common Mistakes:

• Choosing Navigation which manages screen transitions
• Confusing with AsyncStorage for data storage
• Picking Animated which is for animations

3. What will happen when this code runs and the app receives the URL myapp://profile/123?

Linking.addEventListener('url', (event) => {
  console.log(event.url);
});

medium

A. It logs 'myapp://profile/123' to the console

B. It throws a syntax error

C. It opens the profile screen automatically

D. It does nothing because the listener is incorrect

Solution

1. Step 1: Understand the event listener

   The code listens for 'url' events and logs the event.url string.

2. Step 2: Analyze the URL received

   When the app receives 'myapp://profile/123', the listener logs this exact string.

3. Final Answer:

   It logs 'myapp://profile/123' to the console -> Option A

4. Quick Check:

   Listener logs URL = correct output [OK]

Hint: Listener logs incoming URL string [OK]

Common Mistakes:

• Assuming it opens screen automatically without navigation code
• Thinking the code has syntax errors
• Believing the listener does nothing

4. Identify the error in this deep linking setup code:

Linking.addEventListener('url', handleUrl);

function handleUrl(event) {
  console.log(event);
}

// Later
Linking.removeEventListener('url', handleUrl);

medium

A. removeEventListener should be called with a different event name

B. addEventListener requires a second argument as a string

C. handleUrl function should return a value

D. removeEventListener is deprecated; use remove() on the subscription

Solution

1. Step 1: Check React Native Linking API usage

   In recent React Native versions, addEventListener returns a subscription object with a remove() method.

2. Step 2: Identify correct removal method

   removeEventListener is deprecated; you should call subscription.remove() instead.

3. Final Answer:

   removeEventListener is deprecated; use remove() on the subscription -> Option D

4. Quick Check:

   Use subscription.remove() not removeEventListener [OK]

Hint: Use subscription.remove() to stop listening [OK]

Common Mistakes:

• Calling removeEventListener which is deprecated
• Expecting handleUrl to return a value
• Passing wrong argument types to addEventListener

5. You want your React Native app to open the screen showing details for a product when a user clicks a link like myshop://product/42. Which steps are necessary to implement this deep linking behavior correctly?

hard

A. Configure URL scheme in app settings, listen for URL events, parse product ID, navigate to product screen

B. Only listen for URL events and log them; navigation happens automatically

C. Use AsyncStorage to save the URL, then read it on app start

D. Set up a web server to redirect links to the app

Solution

1. Step 1: Configure app to handle custom URL scheme

   You must set up your app to recognize 'myshop://' links in platform config files.

2. Step 2: Listen for URL events and parse the product ID

   Use Linking API to detect incoming URLs and extract the product ID from the URL path.

3. Step 3: Navigate to the product screen with the parsed ID

   Use your navigation library to open the product detail screen with the correct ID.

4. Final Answer:

   Configure URL scheme in app settings, listen for URL events, parse product ID, navigate to product screen -> Option A

5. Quick Check:

   Full deep linking setup = Configure URL scheme in app settings, listen for URL events, parse product ID, navigate to product screen [OK]

Hint: Setup scheme, listen URL, parse, navigate [OK]

Common Mistakes:

• Assuming navigation happens automatically without code
• Using AsyncStorage instead of URL handling
• Thinking a web server is needed for deep linking