Cloud Storage in React Native - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Firebase storage module in React Native.

React Native

import storage from '@react-native-firebase/[1]';

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

Afirestore

Bauth

Cstorage

Ddatabase

Attempts:

3 left

💡 Hint

Common Mistakes

Using firestore or auth instead of storage.

Forgetting the '@react-native-firebase/' prefix.

The Firebase storage module is imported using '@react-native-firebase/storage'.

2fill in blank

medium

Complete the code to get a reference to a file named 'image.jpg' in Firebase Storage.

React Native

const reference = storage().ref('[1]');

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Aimages\image.jpg

Bimages/image.jpg

C/image.jpg

Dimage.jpg

Attempts:

3 left

💡 Hint

Common Mistakes

Using backslashes instead of forward slashes.

Adding a leading slash which is not needed.

The ref() method takes the file path as a string. 'image.jpg' is the correct relative path.

3fill in blank

hard

Fix the error in the code to upload a file to Firebase Storage using React Native.

React Native

await reference.[1](filePath);

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AputFile

BuploadFile

Cupload

Dput

Attempts:

3 left

💡 Hint

Common Mistakes

Using upload or uploadFile which do not exist.

Using put which is for web SDK, not React Native.

The correct method to upload a local file in React Native Firebase Storage is putFile().

4fill in blank

hard

Fill both blanks to download the URL of a stored file and log it.

React Native

const url = await reference.[1]();
console.[2](url);

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AgetDownloadURL

Blog

Cwarn

DgetUrl

Attempts:

3 left

💡 Hint

Common Mistakes

Using getUrl which is not a valid method.

Using console.warn instead of console.log.

getDownloadURL() fetches the file URL, and console.log() prints it to the console.

5fill in blank

hard

Fill all three blanks to delete a file from Firebase Storage and handle errors.

React Native

try {
  await reference.[1]();
  console.[2]('File deleted');
} catch (error) {
  console.[3]('Delete failed', error);
}

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

Adelete

Blog

Cerror

Dwarn

Attempts:

3 left

💡 Hint

Common Mistakes

Using remove() instead of delete().

Using console.warn for errors instead of console.error.

The delete() method removes the file. console.log() shows success, and console.error() shows errors.

Practice

1.

What is the main purpose of Cloud Storage in a React Native app?

easy

A. To save and retrieve files online easily

B. To create user interfaces

C. To manage app navigation

D. To handle app state locally

Solution

1. Step 1: Understand Cloud Storage role

   Cloud Storage is used to save and get files online, not for UI or navigation.

2. Step 2: Match purpose with options

   Only To save and retrieve files online easily describes saving and retrieving files online.

3. Final Answer:

   To save and retrieve files online easily -> Option A

4. Quick Check:

   Cloud Storage = Save/Get files online [OK]

Hint: Cloud Storage is for files, not UI or navigation [OK]

Common Mistakes:

• Confusing Cloud Storage with UI components
• Thinking Cloud Storage manages app navigation
• Assuming Cloud Storage handles local state

2.

Which of the following is the correct way to create a reference to a file named image.jpg in Cloud Storage?

const storage = getStorage();
const ref = ?

easy

A. getRef('image.jpg')

B. storage.ref('image.jpg')

C. ref(storage, 'image.jpg')

D. storage.getReference('image.jpg')

Solution

1. Step 1: Recall correct syntax for reference

   In React Native Firebase, use ref(storage, 'filename') to create a reference.

2. Step 2: Check options for correct function

   Only ref(storage, 'image.jpg') uses ref(storage, 'image.jpg') correctly.

3. Final Answer:

   ref(storage, 'image.jpg') -> Option C

4. Quick Check:

   Reference creation = ref(storage, 'filename') [OK]

Hint: Use ref(storage, 'filename') to create file reference [OK]

Common Mistakes:

• Using storage.ref() which is not valid in React Native
• Calling getRef() which does not exist
• Using storage.getReference() which is incorrect

3.

What will the following code do?

const storage = getStorage();
const fileRef = ref(storage, 'docs/report.pdf');
await uploadBytes(fileRef, fileData);
const url = await getDownloadURL(fileRef);
console.log(url);

medium

A. Upload the file and print its download URL

B. Only upload the file without printing URL

C. Print the URL without uploading the file

D. Cause a syntax error due to missing await

Solution

1. Step 1: Analyze uploadBytes usage

   The code uploads fileData to 'docs/report.pdf' using uploadBytes with await.

2. Step 2: Analyze getDownloadURL usage

   After upload, it gets the file's URL and prints it with console.log.

3. Final Answer:

   Upload the file and print its download URL -> Option A

4. Quick Check:

   Upload + get URL = print URL [OK]

Hint: uploadBytes then getDownloadURL prints URL [OK]

Common Mistakes:

• Thinking getDownloadURL works before upload
• Missing await causing runtime errors
• Assuming uploadBytes does not upload file

4.

Identify the error in this code snippet for uploading a file:

const storage = getStorage();
const fileRef = ref(storage, 'photos/pic.png');
uploadFile(fileRef, fileData);
const url = await getDownloadURL(fileRef);
console.log(url);

medium

A. ref function is used incorrectly

B. Missing await before uploadFile

C. getDownloadURL cannot be awaited

D. uploadFile is not a valid function

Solution

1. Step 1: Check function names for uploading

   The correct function to upload is uploadBytes, not uploadFile.

2. Step 2: Verify other code parts

   getDownloadURL can be awaited and ref usage is correct.

3. Final Answer:

   uploadFile is not a valid function -> Option D

4. Quick Check:

   uploadBytes is correct upload function [OK]

Hint: Use uploadBytes, not uploadFile [OK]

Common Mistakes:

• Using uploadFile instead of uploadBytes
• Forgetting to await uploadBytes
• Misusing getDownloadURL without await

5.

You want to upload a profile picture and then immediately show it in your app. Which sequence of steps is correct?

1. Get a reference to the file location
2. Upload the file using uploadBytes
3. Get the download URL using getDownloadURL
4. Display the image using the URL

hard

A. 1 -> 3 -> 2 -> 4

B. 1 -> 2 -> 3 -> 4

C. 2 -> 1 -> 3 -> 4

D. 3 -> 1 -> 2 -> 4

Solution

1. Step 1: Create file reference first

   You must first get a reference to where the file will be stored.

2. Step 2: Upload file using uploadBytes

   Upload the file to that reference location.

3. Step 3: Get download URL after upload

   Only after upload can you get the file's URL.

4. Step 4: Display image using URL

   Use the URL to show the image in your app.

5. Final Answer:

   1 -> 2 -> 3 -> 4 -> Option B

6. Quick Check:

   Reference -> Upload -> URL -> Display [OK]

Hint: Reference, upload, get URL, then display [OK]

Common Mistakes:

• Trying to get URL before uploading
• Uploading before creating reference
• Displaying image without URL