Resource-based route organization in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new Express router.

Express

const express = require('express');
const router = express.[1]();

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

ARouter

Broute

Capp

Dlisten

Attempts:

3 left

💡 Hint

Common Mistakes

Using express.route() instead of express.Router()

Using express.app() which does not exist

Use express.Router() to create a new router instance.

2fill in blank

medium

Complete the code to define a GET route for '/users' that sends a JSON response.

Express

router.[1]('/users', (req, res) => {
  res.json({ message: 'List of users' });
});

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

Aget

Bput

Cdelete

Dpost

Attempts:

3 left

💡 Hint

Common Mistakes

Using post instead of get

Using put or delete which are for other actions

The GET method is used to retrieve data, so use router.get() for this route.

3fill in blank

hard

Fix the error in the route path to correctly capture a user ID parameter.

Express

router.get('/users/[1]', (req, res) => {
  const userId = req.params.id;
  res.send(`User ID: ${userId}`);
});

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

A:userId

B:id

CuserId

Did

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the colon

Using a different parameter name than accessed in code

Route parameters start with a colon and the name must match the code accessing req.params.id. So use :id.

4fill in blank

hard

Fill both blanks to export the router and import it in the main app file.

Express

// In routes/users.js
const express = require('express');
const router = express.Router();
// ... define routes ...
module.exports = [1];

// In app.js
const express = require('express');
const app = express();
const usersRouter = require('./routes/users');
app.use('/users', [2]);

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

Arouter

Bapp

CusersRouter

Dexpress

Attempts:

3 left

💡 Hint

Common Mistakes

Exporting 'app' instead of 'router'

Using 'router' directly in app.use instead of 'usersRouter'

Export the router as router and import it as usersRouter in the main app, then use app.use('/users', usersRouter).

5fill in blank

hard

Fill all three blanks to create a resource-based route for posts with GET, POST, and DELETE methods.

Express

const express = require('express');
const router = express.Router();

router.[1]('/posts', (req, res) => {
  res.send('Get all posts');
});

router.[2]('/posts', (req, res) => {
  res.send('Create a post');
});

router.[3]('/posts/:id', (req, res) => {
  res.send(`Delete post ${req.params.id}`);
});

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

Aget

Bpost

Cdelete

Dput

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing HTTP methods like using PUT instead of POST

Using GET for deleting resources

Use get to retrieve posts, post to create a post, and delete to remove a post by ID.

Practice

1. What is the main benefit of organizing routes by resource in an Express app?

easy

A. It groups related routes together for better code organization.

B. It automatically generates HTML pages for each resource.

C. It prevents users from accessing the API without a password.

D. It makes the server run faster by caching routes.

Solution

1. Step 1: Understand resource-based route organization

   Resource-based organization groups routes by the data or resource they manage, like users or products.

2. Step 2: Identify the main benefit

   This grouping helps keep code modular and easier to maintain by keeping related routes together.

3. Final Answer:

   It groups related routes together for better code organization. -> Option A

4. Quick Check:

   Grouping routes by resource = better organization [OK]

Hint: Think about grouping similar things together for neatness [OK]

Common Mistakes:

• Confusing route grouping with security features
• Assuming route organization affects server speed
• Thinking routes auto-generate HTML pages

2. Which of the following is the correct way to create a router for a resource named books in Express?

easy

A. const booksRouter = new express.Router();

B. const booksRouter = express.createRouter();

C. const booksRouter = express.Router();

D. const booksRouter = express.route('books');

Solution

1. Step 1: Recall Express Router creation syntax

   Express provides a Router() method on the express object to create modular route handlers.

2. Step 2: Match the correct syntax

   The correct syntax is express.Router(), not createRouter() or new express.Router().

3. Final Answer:

   const booksRouter = express.Router(); -> Option C

4. Quick Check:

   Use express.Router() to create routers [OK]

Hint: Remember: Router is a method, not a constructor or create function [OK]

Common Mistakes:

• Using new keyword with Router
• Calling a non-existent createRouter method
• Using express.route instead of express.Router

3. Given this Express router code for a users resource:

const express = require('express');
const router = express.Router();

router.get('/', (req, res) => res.send('List users'));
router.post('/', (req, res) => res.send('Create user'));
router.get('/:id', (req, res) => res.send(`Get user ${req.params.id}`));

module.exports = router;

What will be the response when a client sends a GET request to /users/42?

medium

A. List users

B. Get user 42

C. 404 Not Found

D. Create user

Solution

1. Step 1: Identify the matching route for GET /users/42

   The route router.get('/:id', ...) matches GET requests with a parameter after /users/.

2. Step 2: Understand the response sent

   The handler sends back the string Get user 42 using the id parameter from the URL.

3. Final Answer:

   Get user 42 -> Option B

4. Quick Check:

   GET /users/:id returns 'Get user {id}' [OK]

Hint: Match URL pattern with route parameters carefully [OK]

Common Mistakes:

• Confusing POST and GET routes
• Ignoring route parameters in URL
• Assuming root path '/' matches /users/42

4. Consider this Express router code snippet:

const router = express.Router();

router.get('/items', (req, res) => res.send('All items'));
router.get('/items/:id', (req, res) => res.send(`Item ${req.params.id}`));
router.post('/items', (req, res) => res.send('Add item'));

module.exports = router;

When mounting this router in the main app with app.use('/api', router);, what is the correct URL to get the response 'Item 5'?

medium

A. /api/items/5

B. /items/5

C. /api/items

D. /items

Solution

1. Step 1: Understand router mounting path

   The router is mounted at /api, so all routes inside it are prefixed with /api.

2. Step 2: Match the route for getting item with id 5

   The route /items/:id inside the router becomes /api/items/:id in the app.

3. Final Answer:

   /api/items/5 -> Option A

4. Quick Check:

   Router prefix + route path = full URL [OK]

Hint: Add router prefix before route path when calling URLs [OK]

Common Mistakes:

• Ignoring the router prefix when calling URLs
• Using root path instead of mounted path
• Confusing POST and GET URLs

5. You want to organize routes for a products resource using Express Router. You need to support listing all products, creating a product, getting a product by ID, updating a product by ID, and deleting a product by ID.

Which of the following router setups correctly implements all these routes following resource-based route organization?

hard

A. const router = express.Router();
router.get('/products', ...);
router.post('/products', ...);
router.get('/products/:id', ...);
router.put('/products/:id', ...);
router.delete('/products/:id', ...);

B. const router = express.Router();
router.get('/list', ...);
router.post('/create', ...);
router.get('/get/:id', ...);
router.put('/update/:id', ...);
router.delete('/delete/:id', ...);

C. const router = express.Router();
router.get('/products/all', ...);
router.post('/products/new', ...);
router.get('/products/get/:id', ...);
router.put('/products/update/:id', ...);
router.delete('/products/remove/:id', ...);

D. const router = express.Router();
router.get('/', ...);
router.post('/', ...);
router.get('/:id', ...);
router.put('/:id', ...);
router.delete('/:id', ...);

Solution

1. Step 1: Understand resource-based route organization with routers

   When using Express Router for a resource, routes inside the router use relative paths like '/', '/:id' because the router is mounted on the resource path (e.g., '/products').

2. Step 2: Identify the correct route paths

   const router = express.Router(); router.get('/', ...); router.post('/', ...); router.get('/:id', ...); router.put('/:id', ...); router.delete('/:id', ...); uses relative paths inside the router, which is the correct pattern. The router would be mounted with app.use('/products', router).

3. Step 3: Compare with other options

   const router = express.Router(); router.get('/products', ...); router.post('/products', ...); router.get('/products/:id', ...); router.put('/products/:id', ...); router.delete('/products/:id', ...); repeats the resource name in every route, which is redundant inside a router. The remaining options use non-standard paths that don't follow REST conventions.

4. Final Answer:

   const router = express.Router(); router.get('/', ...); router.post('/', ...); router.get('/:id', ...); router.put('/:id', ...); router.delete('/:id', ...); -> Option D

5. Quick Check:

   Use relative paths in router, mount on resource path [OK]

Hint: Inside router, use relative paths; mount router on resource path [OK]

Common Mistakes:

• Repeating resource name in every route inside router
• Using non-RESTful or verbose route paths
• Not mounting router on resource path