Deep linking basics in React Native - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is deep linking in mobile apps?

Deep linking is a way to open a specific page or screen inside a mobile app directly from a link, instead of just opening the app's home screen.

intermediate

What is the difference between a universal link and a custom URL scheme?

A universal link uses standard web URLs that open the app if installed or the website if not. A custom URL scheme uses a special app-defined prefix like "myapp://" to open the app.

beginner

Which React Native library is commonly used to handle deep linking?

React Navigation is commonly used in React Native apps to handle deep linking and navigation between screens.

intermediate

Why is it important to configure deep linking in both Android and iOS?

Because Android and iOS handle links differently, you must set up deep linking separately for each platform to ensure links open the app correctly on both.

beginner

What happens if a deep link is opened but the app is not installed?

If the app is not installed, universal links open the website URL instead, while custom URL schemes usually do nothing or show an error.

What does a deep link do in a mobile app?

A Updates the app automatically

B Closes the app

C Uninstalls the app

D Opens a specific screen inside the app

Deep links open a specific screen or content inside the app directly.

Which of these is an example of a custom URL scheme?

A myapp://profile/123

B ftp://fileserver.com

C https://example.com/home

D mailto:[e-mail]

Custom URL schemes use a unique prefix like "myapp://" to open the app.

Which React Native tool helps manage deep linking navigation?

A Expo Camera

B Redux

C React Navigation

D Axios

React Navigation handles screen navigation and deep linking in React Native apps.

What should you do to support deep linking on iOS?

A Install Android Studio

B Configure URL types in Xcode

C Use Google Play Store

D Disable internet access

On iOS, you configure URL types in Xcode to support deep linking.

If a user clicks a universal link but the app is not installed, what happens?

A The website opens in the browser

B The app opens anyway

C Nothing happens

D The phone restarts

Universal links open the website if the app is not installed.

Explain what deep linking is and why it is useful in mobile apps.

Think about how clicking a link can take you straight to a specific page inside an app.

Describe the difference between universal links and custom URL schemes in deep linking.

Consider how links behave differently depending on the link type and app installation.

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