PUT and DELETE requests in Angular - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to send a PUT request using Angular's HttpClient.

Angular

this.http.[1]('https://api.example.com/items/1', updatedItem).subscribe(response => {
  console.log('Item updated', response);
});

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

Aput

Bpost

Cget

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'post' instead of 'put' for updating data.

Using 'get' which only retrieves data.

The put method sends a PUT request to update data on the server.

2fill in blank

medium

Complete the code to send a DELETE request to remove an item.

Angular

this.http.[1]('https://api.example.com/items/1').subscribe(() => {
  console.log('Item deleted');
});

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

Aput

Bdelete

Cpost

Dget

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'post' or 'put' instead of 'delete' to remove data.

Using 'get' which only fetches data.

The delete method sends a DELETE request to remove data from the server.

3fill in blank

hard

Fix the error in the code to correctly send a PUT request with HttpClient.

Angular

this.http.[1]('https://api.example.com/items/1', updatedItem).subscribe(response => {
  console.log('Updated', response);
});

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

Apost

Bget

Cdelete

Dput

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the data argument in PUT request.

Using 'post' or 'get' instead of 'put'.

The PUT request requires both the URL and the data to update. The method is put.

4fill in blank

hard

Fill both blanks to send a DELETE request and handle the response.

Angular

this.http.[1]('https://api.example.com/items/1').subscribe({
  next: () => console.log('Deleted'),
  error: ([2]) => console.error('Error', [2])
});

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

Adelete

Berr

Cerror

Dresponse

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'post' or 'put' instead of 'delete'.

Using a generic name like 'response' for the error parameter.

Use delete to send the request and a variable like err to catch errors.

5fill in blank

hard

Fill all three blanks to send a PUT request with updated data and handle success and error.

Angular

this.http.[1]('https://api.example.com/items/1', updatedItem).subscribe({
  next: ([2]) => console.log('Success', [2]),
  error: ([3]) => console.error('Failed', [3])
});

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

Aput

Bresponse

Cerror

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'delete' instead of 'put' for updating.

Confusing the names of success and error parameters.

Use put to update data, and name the success and error parameters clearly.

Practice

1. What is the main purpose of a PUT request in Angular's HttpClient?

easy

A. To retrieve data from the server

B. To delete a resource from the server

C. To update an existing resource by sending the full new data

D. To partially update a resource

Solution

1. Step 1: Understand HTTP methods

   PUT is used to update or replace an existing resource completely.

2. Step 2: Compare with other methods

   DELETE removes data, GET retrieves data, PATCH partially updates data.

3. Final Answer:

   To update an existing resource by sending the full new data -> Option C

4. Quick Check:

   PUT updates full resource = A [OK]

Hint: PUT replaces full data, DELETE removes resource [OK]

Common Mistakes:

• Confusing PUT with DELETE
• Thinking PUT partially updates data
• Mixing GET with PUT

2. Which of the following is the correct syntax to send a DELETE request using Angular's HttpClient?

easy

A. this.http.delete('api/items/1').subscribe();

B. this.http.put('api/items/1').subscribe();

C. this.http.get('api/items/1').subscribe();

D. this.http.post('api/items/1').subscribe();

Solution

1. Step 1: Identify the method for DELETE

   Angular's HttpClient uses delete() to send DELETE requests.

2. Step 2: Check syntax correctness

   The method call this.http.delete('api/items/1').subscribe(); correctly sends a DELETE request and subscribes to the response.

3. Final Answer:

   this.http.delete('api/items/1').subscribe(); -> Option A

4. Quick Check:

   DELETE method uses http.delete() [OK]

Hint: Use http.delete() for DELETE requests [OK]

Common Mistakes:

• Using http.put() instead of http.delete()
• Forgetting to subscribe to the observable
• Using http.post() for deleting

3. Given this Angular code snippet, what will be logged after the PUT request completes successfully?

const updatedItem = { id: 5, name: 'New Name' };
this.http.put('api/items/5', updatedItem).subscribe(response => {
  console.log(response);
});

medium

A. The updated item object returned from the server

B. An error message because PUT requires no body

C. Nothing, because PUT does not return data

D. The original item before update

Solution

1. Step 1: Understand PUT request behavior

   PUT sends the full updated data and usually returns the updated resource from the server.

2. Step 2: Analyze the subscription callback

   The response logged is the server's reply, typically the updated item object.

3. Final Answer:

   The updated item object returned from the server -> Option A

4. Quick Check:

   PUT returns updated data = A [OK]

Hint: PUT usually returns updated resource in response [OK]

Common Mistakes:

• Assuming PUT returns no data
• Confusing PUT with DELETE response
• Expecting original item instead of updated

4. Identify the error in this Angular DELETE request code:

this.http.delete('api/items').subscribe(response => {
  console.log('Item deleted');
});

Assuming the API requires an item ID to delete a specific item.

medium

A. DELETE requests cannot be sent without a request body

B. The URL is missing the item ID to specify which item to delete

C. The subscribe method is missing a parameter

D. The console.log statement is incorrect

Solution

1. Step 1: Check the URL for DELETE request

   The URL 'api/items' does not specify which item to delete; an ID is needed.

2. Step 2: Understand API requirements

   APIs usually require an ID in the URL like 'api/items/1' to delete a specific item.

3. Final Answer:

   The URL is missing the item ID to specify which item to delete -> Option B

4. Quick Check:

   DELETE URL needs item ID = C [OK]

Hint: DELETE URL must include resource ID to delete [OK]

Common Mistakes:

• Sending DELETE without specifying resource ID
• Thinking DELETE needs a request body
• Ignoring subscribe callback

5. You want to update a user's profile and then delete their old profile picture in Angular. Which sequence of HttpClient calls correctly applies PUT and DELETE requests?

// Update user profile
this.http.put('api/users/10', updatedUser).subscribe(() => {
  // Delete old profile picture
  this.http.delete('api/pictures/oldPicId').subscribe(() => {
    console.log('Profile updated and old picture deleted');
  });
});

hard

A. DELETE request first to delete picture, then PUT request inside DELETE's subscribe to update profile

B. Use only PUT request to update profile and delete picture together

C. Send PUT and DELETE requests simultaneously without waiting for response

D. PUT request first to update profile, then DELETE request inside PUT's subscribe to delete picture

Solution

1. Step 1: Understand request order

   First update the user profile with PUT, then delete the old picture after success.

2. Step 2: Analyze code structure

   DELETE request is inside PUT's subscribe callback, ensuring sequential execution.

3. Step 3: Evaluate other options

   Deleting first may remove picture before profile update; simultaneous calls lack order; PUT cannot delete picture.

4. Final Answer:

   PUT request first to update profile, then DELETE request inside PUT's subscribe to delete picture -> Option D

5. Quick Check:

   Update then delete sequentially = B [OK]

Hint: Chain DELETE inside PUT subscribe for correct order [OK]

Common Mistakes:

• Deleting before updating causing data mismatch
• Sending requests simultaneously without order
• Trying to delete picture with PUT request