Why REST design principles matter in Node.js - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a simple GET endpoint using Express that returns a welcome message.

Node.js

app.[1]('/welcome', (req, res) => {
  res.send('Welcome to our API!');
});

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

Aget

Bput

Cpost

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using POST instead of GET for retrieving data.

Confusing HTTP methods and their purposes.

The GET method is used to request data from a server. Here, it defines an endpoint that sends a welcome message.

2fill in blank

medium

Complete the code to parse JSON request bodies in Express using middleware.

Node.js

app.use([1].json());

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

Acors

BbodyParser

Crouter

Dexpress

Attempts:

3 left

💡 Hint

Common Mistakes

Using bodyParser which is deprecated in newer Express versions.

Trying to use unrelated middleware like cors.

Express has built-in middleware called express.json() to parse JSON bodies from incoming requests.

3fill in blank

hard

Fix the error in the route handler to correctly send a JSON response with a status code.

Node.js

app.get('/data', (req, res) => {
  res.status([1]).json({ message: 'Data fetched' });
});

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

A'OK'

B'200'

C200

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Passing status code as a string instead of a number.

Using status text like 'OK' instead of numeric code.

The status code should be a number, not a string. 200 means success.

4fill in blank

hard

Fill both blanks to create a RESTful route that updates a user by ID using the correct HTTP method and URL pattern.

Node.js

app.[1]('/users/[2]', (req, res) => {
  // update user logic
  res.send('User updated');
});

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

Aput

Bpost

C:id

DuserId

Attempts:

3 left

💡 Hint

Common Mistakes

Using POST instead of PUT for updates.

Using incorrect parameter names without colon.

PUT is used to update resources. The URL uses a parameter :id to specify which user to update.

5fill in blank

hard

Fill all three blanks to create a RESTful DELETE route that removes a product by its ID and sends a confirmation message.

Node.js

app.[1]('/products/[2]', (req, res) => {
  const productId = req.params.[3];
  // delete product logic
  res.send(`Product ${productId} deleted`);
});

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

Adelete

B:id

Cid

Dpost

Attempts:

3 left

💡 Hint

Common Mistakes

Using POST instead of DELETE.

Mismatching parameter names in URL and req.params.

DELETE method removes resources. The URL uses :id as a parameter. The handler accesses req.params.id to get the ID.

Practice

1. Why is it important to follow REST design principles when building APIs in Node.js?

easy

A. They make APIs easier to understand and use by following clear rules.

B. They force the use of only one HTTP method for all actions.

C. They require APIs to use XML instead of JSON.

D. They allow APIs to ignore URL structure and focus on data only.

Solution

1. Step 1: Understand REST principles purpose

   REST principles guide API design to be clear and predictable by using standard HTTP methods and resource URLs.

2. Step 2: Evaluate options against REST goals

   They make APIs easier to understand and use by following clear rules. matches the goal of making APIs easier to understand and use. The other options contradict REST principles.

3. Final Answer:

   They make APIs easier to understand and use by following clear rules. -> Option A

4. Quick Check:

   REST clarity = A [OK]

Hint: REST means clear rules for APIs, not forcing one method [OK]

Common Mistakes:

• Thinking REST requires only one HTTP method
• Confusing REST with data format rules
• Ignoring URL structure importance

2. Which HTTP method is correctly paired with its RESTful action in Node.js API design?

easy

A. GET to create a new resource

B. PUT to update an existing resource

C. POST to retrieve data

D. DELETE to fetch resource details

Solution

1. Step 1: Recall REST HTTP method meanings

   GET retrieves data, POST creates, PUT updates, DELETE removes resources.

2. Step 2: Match methods to actions

   PUT to update an existing resource correctly pairs PUT with updating a resource. Other options mismatch methods and actions.

3. Final Answer:

   PUT to update an existing resource -> Option B

4. Quick Check:

   PUT = update [OK]

Hint: PUT updates, POST creates, GET reads, DELETE removes [OK]

Common Mistakes:

• Mixing POST and GET actions
• Using DELETE to fetch data
• Confusing PUT with POST

3. Consider this Node.js Express route:

app.delete('/users/:id', (req, res) => {
  // delete user logic
  res.send('User deleted');
});

What is the expected behavior when a client sends a DELETE request to /users/123?

medium

A. It retrieves user 123's details.

B. It updates user 123's information.

C. It deletes user 123 and responds with confirmation.

D. It creates a new user with ID 123.

Solution

1. Step 1: Analyze the HTTP method and route

   The route uses DELETE method on '/users/:id', indicating deletion of a user by ID.

2. Step 2: Understand the response

   The handler sends 'User deleted' after deletion logic, confirming the user is deleted.

3. Final Answer:

   It deletes user 123 and responds with confirmation. -> Option C

4. Quick Check:

   DELETE /users/:id = delete user [OK]

Hint: DELETE routes remove resources and confirm action [OK]

Common Mistakes:

• Confusing DELETE with GET or POST
• Expecting data retrieval on DELETE
• Ignoring route parameter usage

4. You wrote this Node.js Express route:

app.post('/items/:id', (req, res) => {
  // update item logic
  res.send('Item updated');
});

What is the main REST design issue with this code?

medium

A. POST should not be used to update an existing resource; PUT is preferred.

B. The route URL should not include an ID parameter.

C. The response message should be 'Item created' instead.

D. POST cannot have a request body in REST.

Solution

1. Step 1: Identify HTTP method and action mismatch

   POST is typically used to create new resources, not update existing ones.

2. Step 2: Apply REST principle for updating

   PUT is the correct method to update a resource identified by an ID in the URL.

3. Final Answer:

   POST should not be used to update an existing resource; PUT is preferred. -> Option A

4. Quick Check:

   Update = PUT, not POST [OK]

Hint: Use PUT to update existing resources, not POST [OK]

Common Mistakes:

• Using POST for updates
• Ignoring URL parameter meaning
• Confusing response messages with method purpose

5. You want to design a RESTful API in Node.js to manage books. Which URL and HTTP method combination best follows REST principles to update the title of a book with ID 42?

hard

A. POST /books/42 with new title in body

B. GET /books/update/42 with new title in query

C. DELETE /books/42 with new title in body

D. PUT /books/42 with new title in body

Solution

1. Step 1: Identify RESTful update method

   PUT is the standard HTTP method to update an existing resource fully or partially.

2. Step 2: Check URL structure for resource identification

   /books/42 correctly identifies the book resource by ID, matching REST URL design.

3. Step 3: Evaluate other options

   POST is for creation, GET should not change data, DELETE removes resource, so they are incorrect here.

4. Final Answer:

   PUT /books/42 with new title in body -> Option D

5. Quick Check:

   Update book = PUT /books/42 [OK]

Hint: Use PUT with resource URL to update data [OK]

Common Mistakes:

• Using POST to update existing resource
• Using GET to change data
• Misusing DELETE for updates