HTTP methods for CRUD operations in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to handle creating a new resource using the correct HTTP method.

Express

app.[1]('/items', (req, res) => {
  res.send('Create item');
});

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

Aget

Bpost

Cput

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using GET instead of POST for creating resources.

The POST method is used to create new resources on the server.

2fill in blank

medium

Complete the code to handle reading a resource using the correct HTTP method.

Express

app.[1]('/items/:id', (req, res) => {
  res.send('Read item ' + req.params.id);
});

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

Aget

Bpost

Cput

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using POST instead of GET for reading data.

The GET method is used to read or retrieve data from the server.

3fill in blank

hard

Fix the error in the code by choosing the correct HTTP method to update a resource.

Express

app.[1]('/items/:id', (req, res) => {
  res.send('Update item ' + req.params.id);
});

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

Aput

Bpost

Cget

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using POST or GET instead of PUT for updating resources.

The PUT method is used to update an existing resource completely.

4fill in blank

hard

Fill both blanks to handle deleting a resource using the correct HTTP method and path.

Express

app.[1]('/items/[2]', (req, res) => {
  res.send('Delete item ' + req.params.id);
});

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

Adelete

B:id

Cpost

Dget

Attempts:

3 left

💡 Hint

Common Mistakes

Using GET or POST instead of DELETE for removing resources.

Missing the ':id' parameter in the path.

DELETE method is used to remove a resource, and ':id' is the path parameter for the resource ID.

5fill in blank

hard

Fill all three blanks to create a full CRUD route for updating an item by ID using Express.

Express

app.[1]('/items/[2]', (req, res) => {
  const id = req.params.[3];
  res.send('Update item ' + id);
});

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

Aput

B:id

Cid

Dpost

Attempts:

3 left

💡 Hint

Common Mistakes

Using POST instead of PUT for update.

Not including ':id' in the route path.

Incorrect parameter name when accessing req.params.

PUT is the HTTP method for updating, ':id' is the route parameter, and 'id' accesses that parameter in code.

Practice

1. Which HTTP method is typically used in Express to retrieve data from a server?

easy

A. PUT

B. POST

C. DELETE

D. GET

Solution

1. Step 1: Understand HTTP methods purpose

   GET is used to read or retrieve data from the server without changing it.

2. Step 2: Match method to action

   Since the question asks for retrieving data, GET is the correct method.

3. Final Answer:

   GET -> Option D

4. Quick Check:

   Retrieve data = GET [OK]

Hint: GET always reads data without changing it [OK]

Common Mistakes:

• Confusing POST with GET for reading data
• Using DELETE to get data
• Thinking PUT retrieves data

2. Which of the following is the correct Express syntax to handle a POST request to the path /users?

easy

A. app.get('/users', (req, res) => { ... })

B. app.put('/users', (req, res) => { ... })

C. app.post('/users', (req, res) => { ... })

D. app.delete('/users', (req, res) => { ... })

Solution

1. Step 1: Identify method for creating data

   POST is used to create new data on the server.

2. Step 2: Match Express syntax to POST

   app.post('/users', ...) correctly handles POST requests to /users.

3. Final Answer:

   app.post('/users', (req, res) => { ... }) -> Option C

4. Quick Check:

   POST creates data = app.post() [OK]

Hint: Use app.post() for creating new data routes [OK]

Common Mistakes:

• Using app.get() for POST requests
• Confusing app.put() with app.post()
• Writing app.delete() for creation

3. What will be the response status code if you define this Express route and send a request to PUT /items/5?

app.put('/items/:id', (req, res) => {
  res.status(200).send(`Updated item ${req.params.id}`);
});

medium

A. 200 OK

B. 201 Created

C. 500 Internal Server Error

D. 404 Not Found

Solution

1. Step 1: Analyze route and method

   The route handles PUT requests to /items/:id, so /items/5 matches with id=5.

2. Step 2: Check response status code

   The code explicitly sets status 200 and sends a message, so response status is 200 OK.

3. Final Answer:

   200 OK -> Option A

4. Quick Check:

   PUT route sends status 200 = 200 OK [OK]

Hint: Check res.status() for response code [OK]

Common Mistakes:

• Assuming 201 Created for PUT
• Thinking 404 if route exists
• Confusing 500 error without code

4. Identify the error in this Express route meant to delete a user by ID:

app.delete('/users/:id', (req, res) => {
  const userId = req.params;
  deleteUser(userId);
  res.send('User deleted');
});

medium

A. req.params should be req.params.id to get the ID

B. deleteUser is not a valid Express method

C. res.send should be res.status(204).send()

D. Route path should be '/user/:id' not '/users/:id'

Solution

1. Step 1: Check how userId is assigned

   req.params is an object; to get the ID string, use req.params.id.

2. Step 2: Understand deleteUser usage

   deleteUser likely expects an ID string, so passing the whole params object is wrong.

3. Final Answer:

   req.params should be req.params.id to get the ID -> Option A

4. Quick Check:

   Use req.params.id for ID value [OK]

Hint: Use req.params.id to access route parameters [OK]

Common Mistakes:

• Passing whole req.params object instead of ID
• Confusing route path naming
• Assuming deleteUser is Express built-in

5. You want to update a user's email fully using Express. Which HTTP method and route setup is best practice for this operation?

hard

A. app.post('/users/:id', (req, res) => { ... })

B. app.put('/users/:id', (req, res) => { ... })

C. app.get('/users/:id', (req, res) => { ... })

D. app.delete('/users/:id', (req, res) => { ... })

Solution

1. Step 1: Identify method for full update

   PUT is the HTTP method used to fully update existing data.

2. Step 2: Match route to user ID

   Route '/users/:id' targets a specific user by ID for update.

3. Final Answer:

   app.put('/users/:id', (req, res) => { ... }) -> Option B

4. Quick Check:

   Full update = PUT method [OK]

Hint: Use PUT with ID route for full updates [OK]

Common Mistakes:

• Using POST for updates instead of creation
• Using GET or DELETE for updating data
• Not including :id in route for specific user