MEAN Express.js Middleware and Routing 5

Question 1

How can you make an Express route parameter optional?

Accepted Answer

Append `?` after the parameter name: `/:id?`

Answer

Appending `?` to a route parameter name, e.g., `/:id?`, makes that segment optional so the route matches both `/users` and `/users/42`.

Question 2

Which statement about `app.use()` path matching is correct?

Accepted Answer

`app.use('/api')` also matches `/api/users` and `/api/products`

Answer

`app.use()` performs prefix matching, so mounting on `/api` will match any request whose URL starts with `/api`, including `/api/users`.

Question 3

What does the `router.param()` method do in Express?

Accepted Answer

Registers a callback that runs whenever a specific route parameter is present

Answer

`router.param(name, callback)` adds a pre-processing callback that fires automatically whenever a route containing the named parameter is matched.

Question 4

In Express, which middleware must be added before route definitions to parse `application/x-www-form-urlencoded` POST bodies?

Accepted Answer

express.urlencoded({ extended: false })

Answer

`express.urlencoded()` parses URL-encoded form data sent in POST requests, populating `req.body` with the parsed key-value pairs.

Question 5

What is a potential security risk of setting `express.static` to serve the project root directory?

Accepted Answer

It may expose sensitive files like `package.json` or `.env` to public access

Answer

Serving from the project root means all files — including source code, environment files, and configs — become publicly downloadable.

MEAN - Stack Development Practice Test