Push notifications (expo-notifications) in React Native - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Expo Notifications module.

React Native

import * as [1] from 'expo-notifications';

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

ANotifications

BNotification

CExpoNotifications

DExpo_Notifications

Attempts:

3 left

💡 Hint

Common Mistakes

Using singular 'Notification' instead of plural 'Notifications'.

Adding underscores or extra words in the import name.

The correct import is Notifications from expo-notifications. This module handles push notifications in Expo apps.

2fill in blank

medium

Complete the code to request push notification permissions.

React Native

const { status } = await Notifications.[1]Async();

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

ArequestPermissionsAsync

BrequestPermissions

CgetPermissions

DgetPermissionsAsync

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'getPermissions' which only checks permission but does not request.

Omitting 'Async' which is required for the promise-based method.

The method to request permissions asynchronously is requestPermissionsAsync. It asks the user to allow notifications.

3fill in blank

hard

Fix the error in the code to get the Expo push token.

React Native

const tokenData = await Notifications.get[1]Async();

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

APush

BPushToken

CExpoPushToken

DExpoToken

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'getPushTokenAsync' which does not exist.

Mixing up the order of words in the method name.

The correct method is getExpoPushTokenAsync. It returns the token needed to send push notifications to this device.

4fill in blank

hard

Fill both blanks to schedule a notification after 5 seconds.

React Native

await Notifications.scheduleNotificationAsync({
  content: { body: 'Hello!' },
  trigger: { seconds: [1], repeats: [2] }
});

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

A5

Btrue

Cfalse

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Setting repeats to true causes repeated notifications.

Using 10 seconds instead of 5 seconds delay.

The notification should trigger after 5 seconds and not repeat, so seconds: 5 and repeats: false are correct.

5fill in blank

hard

Fill all three blanks to add a notification response listener and remove it properly.

React Native

const subscription = Notifications.addNotificationResponseReceivedListener(response => {
  console.log(response.[1]);
});

// Later to clean up
subscription.[2]();

// To add a notification received listener
const receivedSub = Notifications.addNotificationReceivedListener(notification => {
  console.log(notification.[3]);
});

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

Anotification

Bremove

Crequest

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'request' instead of 'remove' to clean up listeners.

Accessing wrong properties on response or notification objects.

The response object has a notification property. To stop listening, call remove() on the subscription. The notification received listener also uses notification.

Practice

1. What is the main purpose of using expo-notifications in a React Native app?

easy

A. To create animations for app screens

B. To send and receive push notifications to keep users informed

C. To manage app navigation between screens

D. To handle user authentication and login

Solution

1. Step 1: Understand the role of expo-notifications

   The expo-notifications library is designed to handle push notifications in React Native apps.

2. Step 2: Identify the correct purpose

   It allows apps to send and receive notifications, keeping users informed even when the app is closed.

3. Final Answer:

   To send and receive push notifications to keep users informed -> Option B

4. Quick Check:

   expo-notifications = Push notifications [OK]

Hint: Remember: expo-notifications is for alerts, not UI or auth [OK]

Common Mistakes:

• Confusing notifications with navigation or animations
• Thinking expo-notifications manages user login
• Assuming it handles UI styling

2. Which of the following is the correct way to request notification permissions using expo-notifications?

easy

A. await Notifications.requestPermissionsAsync();

B. Notifications.getPermissions();

C. await Notifications.askForPermissions();

D. Notifications.permissionRequest();

Solution

1. Step 1: Recall the correct method name

   The official method to request permissions is requestPermissionsAsync() from expo-notifications.

2. Step 2: Check syntax correctness

   The method is asynchronous and should be awaited: await Notifications.requestPermissionsAsync();

3. Final Answer:

   await Notifications.requestPermissionsAsync(); -> Option A

4. Quick Check:

   Permission request method = requestPermissionsAsync [OK]

Hint: Look for async method starting with 'request' [OK]

Common Mistakes:

• Using non-existent methods like getPermissions or askForPermissions
• Forgetting to await the async call
• Using incorrect method names

3. Given the code snippet below, what will be logged when a notification is received?

import * as Notifications from 'expo-notifications';

Notifications.addNotificationReceivedListener(notification => {
  console.log(notification.request.content.title);
});

// Assume a notification with title 'Hello User' arrives

medium

A. undefined

B. notification

C. Hello User

D. Error: notification is not defined

Solution

1. Step 1: Understand the listener callback

   The listener receives a notification object, and logs notification.request.content.title.

2. Step 2: Match the notification content

   The notification has a title 'Hello User', so that string will be logged.

3. Final Answer:

   Hello User -> Option C

4. Quick Check:

   Logged title = 'Hello User' [OK]

Hint: Listener logs notification title property [OK]

Common Mistakes:

• Expecting the whole notification object to be logged
• Confusing property names or missing nested fields
• Assuming undefined if not familiar with notification structure

4. What is wrong with this code snippet for getting the push token?

import * as Notifications from 'expo-notifications';

const getToken = async () => {
  const token = Notifications.getExpoPushTokenAsync();
  console.log(token);
};

getToken();

medium

A. Missing await before Notifications.getExpoPushTokenAsync()

B. Wrong import statement for Notifications

C. console.log should be inside a .then() block

D. getToken function should not be async

Solution

1. Step 1: Identify async function usage

   The method getExpoPushTokenAsync() returns a Promise and must be awaited.

2. Step 2: Check the code for await

   The code calls Notifications.getExpoPushTokenAsync() without await, so token is a Promise, not the actual token.

3. Final Answer:

   Missing await before Notifications.getExpoPushTokenAsync() -> Option A

4. Quick Check:

   Async calls need await to get result [OK]

Hint: Always await async calls to get actual values [OK]

Common Mistakes:

• Forgetting to await async functions
• Misunderstanding Promises vs values
• Incorrect import statements
• Logging before Promise resolves

5. You want to send a push notification only when the user has granted permission. Which sequence of steps correctly implements this using expo-notifications?

hard

A. Send notification directly without requesting permission or token

B. Get token first with getExpoPushTokenAsync(), then request permission with requestPermissionsAsync()

C. Only request permission and send notification without getting token

D. Request permission with requestPermissionsAsync(), check status, then get token with getExpoPushTokenAsync() if granted

Solution

1. Step 1: Request notification permission

   Use requestPermissionsAsync() to ask the user for permission and check the returned status.

2. Step 2: Get push token if permission granted

   If permission is granted, call getExpoPushTokenAsync() to get the device token for sending notifications.

3. Step 3: Send notification using the token

   Use the token to send push notifications from your server or app.

4. Final Answer:

   Request permission with requestPermissionsAsync(), check status, then get token with getExpoPushTokenAsync() if granted -> Option D

5. Quick Check:

   Permission first, then token, then send [OK]

Hint: Always request permission before getting token [OK]

Common Mistakes:

• Getting token before permission
• Sending notifications without token
• Skipping permission check
• Assuming permission is granted by default