Introduction to Express Quiz

To pass the quiz, you must correctly answer at least 18 of the 20 questions below. # --quizzes-- ## --quiz-- ### --question-- #### --text-- What is the relationship between an API and a web service? #### --distractors-- Every API is a web service, but not every web service is an API. --- APIs and web services are identical concepts. --- Web services only work with REST, while APIs support multiple protocols. #### --answer-- Every web service is an API, but not every API is a web service. ### --question-- #### --text-- Which HTTP header does a client use to tell the server which response format it wants? #### --distractors-- `Content-Type` --- `Authorization` --- `X-Requested-With` #### --answer-- `Accept` ### --question-- #### --text-- What does statelessness mean in a REST architecture? #### --distractors-- The server stores the client's session data between requests. --- The client keeps no state of its own across requests. --- REST restricts all requests to read-only operations. #### --answer-- The server stores no memory of previous requests. ### --question-- #### --text-- Which REST HTTP method is used to remove a resource? #### --distractors-- `GET` --- `POST` --- `PUT` #### --answer-- `DELETE` ### --question-- #### --text-- What is a key advantage of microservices over a monolith? #### --distractors-- Simpler debugging and fewer network calls between services. --- A single shared codebase that all teams contribute to. --- Easier infrastructure management across all services. #### --answer-- Faster development, better fault isolation, and the ability to use different languages per service. ### --question-- #### --text-- What does calling `express()` return? #### --distractors-- A new HTTP server. --- A router object. --- A middleware function. #### --answer-- A new instance of Express application. ### --question-- #### --text-- What is middleware in Express? #### --distractors-- A built-in method used to start the Express server. --- A special type of HTTP method used in REST APIs. --- A built-in tool for serving static files from a directory. #### --answer-- Code that runs between receiving a request and sending a response. ### --question-- #### --text-- What does `app.listen(port, callback)` do in Express? #### --distractors-- Defines a route for incoming requests. --- Loads the Express library. --- Creates a new middleware function. #### --answer-- Starts the server and begins listening for incoming HTTP requests. ### --question-- #### --text-- What is a route parameter in Express? #### --distractors-- A fixed URL path like `/home`. --- A query string appended to the URL. --- A method for serving static files. #### --answer-- A placeholder in the URL prefixed with `:` that captures a dynamic value. ### --question-- #### --text-- How do you access the dynamic value captured from a URL like `/post/42` in an Express route defined as `/post/:postId`? #### --distractors-- `req.query.postId` --- `req.body.postId` --- `req.url.postId` #### --answer-- `req.params.postId` ### --question-- #### --text-- What does `res.json()` do in Express? #### --distractors-- Sends a plain text response. --- Redirects the client to a different URL. --- Renders a template engine view and sends the resulting HTML. #### --answer-- Sends a JSON response and automatically converts a JavaScript object. ### --question-- #### --text-- What does `res.redirect(url)` do in Express? #### --distractors-- Sets the HTTP status code. --- Sends a JSON response. --- Renders a view using a template engine. #### --answer-- Redirects the client to a different URL. ### --question-- #### --text-- What is the purpose of `app.route()` in Express? #### --distractors-- To create a new instance of the Express application. --- To serve static files from a specified directory. --- To define separate routes for different URL paths. #### --answer-- To chain multiple HTTP method handlers for the same path in one block. ### --question-- #### --text-- What does `express.Router()` create? #### --distractors-- A new Express application instance that replaces `app` for handling all server logic. --- A middleware function dedicated to catching and handling route-level errors. --- A built-in static file server that automatically maps files to URL paths. #### --answer-- A router object, similar to a mini Express app, that you define routes on and mount in the main application. ### --question-- #### --text-- How do you mount a router in the main Express app? #### --distractors-- By calling `router.listen()`. --- By calling `router.start()`. --- By calling `app.get()` directly inside the router. #### --answer-- By calling `app.use(path, router)`. ### --question-- #### --text-- Which built-in Express middleware is used to serve static files? #### --distractors-- `express.json()` --- `express.urlencoded()` --- `express.raw()` #### --answer-- `express.static()` ### --question-- #### --text-- What happens when a user requests a static file that does not exist in the directory configured with `express.static()`? #### --distractors-- Express throws an error and crashes the server. --- Express redirects the user to the home page. --- Express creates an empty file at the requested path. #### --answer-- Express automatically responds with a 404. ### --question-- #### --text-- Which of the following is true about SOAP compared to REST? #### --distractors-- SOAP uses JSON and is more flexible than REST, making it ideal for modern applications. --- SOAP is the most widely used web service type today, having replaced REST in most systems. --- SOAP supports multiple response formats, including plain text, JSON, and binary data. #### --answer-- SOAP uses only XML and is common in enterprise systems that need stricter standards and security. ### --question-- #### --text-- What is a route handler in Express? #### --distractors-- A configuration object that maps all available route paths to their HTTP methods. --- A middleware function that automatically intercepts and serves static files from a folder. --- A database connector that processes and handles route-related database queries. #### --answer-- A callback function that runs when a request matches a route, with access to `req` and `res`. ### --question-- #### --text-- What is a benefit of using `express.Router()` instead of defining all routes directly in `app.js`? #### --distractors-- It allows the server to handle significantly more concurrent HTTP requests at once. --- It automatically generates and registers REST API endpoints based on route file names. --- It lets the server start and run without needing to specify a port number. #### --answer-- It separates concerns and keeps the main file clean by moving related routes into their own modules.