feat(curriculum): add express error handling quiz (#67357)

Signed-off-by: Kolade Chris <65571316+Ksound22@users.noreply.github.com>
2026-05-28 10:22:16 +00:00 · 2026-05-23 13:22:54 +01:00
parent 0fcbf74446
commit f9f699e52b
4 changed files with 477 additions and 1 deletions
@@ -7252,6 +7252,12 @@
          "In these lessons, you'll learn about error handling and health checks in Express."
        ]
      },
+      "quiz-error-handling-in-express": {
+        "title": "Error Handling in Express Quiz",
+        "intro": [
+          "Test your knowledge of HTTP status codes, error handling, debugging, logging, health checks, and graceful shutdowns."
+        ]
+      },
      "exam-back-end-development-and-apis-certification": {
        "title": "Back-End Development and APIs Certification Exam",
        "intro": [
@@ -0,0 +1,454 @@
+---
+id: 6a04bbc9815e737ed711622e
+title: Error Handling in Express Quiz
+challengeType: 8
+dashedName: quiz-error-handling-in-express
+---
+
+# --description--
+
+To pass the quiz, you must correctly answer at least 18 of the 20 questions below.
+
+# --quizzes--
+
+## --quiz--
+
+### --question--
+
+#### --text--
+
+What does the HTTP status code 201 mean?
+
+#### --distractors--
+
+The request succeeded with no response body.
+
+---
+
+The client is not authorized to access the resource.
+
+---
+
+The requested resource does not exist.
+
+#### --answer--
+
+A new resource was successfully created.
+
+### --question--
+
+#### --text--
+
+Which status code indicates that the request succeeded but there is no response body?
+
+#### --distractors--
+
+`200`
+
+---
+
+`201`
+
+---
+
+`301`
+
+#### --answer--
+
+`204`
+
+### --question--
+
+#### --text--
+
+What does the `304 Not Modified` status code tell the client?
+
+#### --distractors--
+
+The resource has moved to a new permanent URL.
+
+---
+
+The server is temporarily unavailable for maintenance.
+
+---
+
+Authentication is required to access the resource.
+
+#### --answer--
+
+Nothing has changed, so the client can use its cached version.
+
+### --question--
+
+#### --text--
+
+What is the difference between status codes `401` and `403`?
+
+#### --distractors--
+
+`401` means the resource is not found while `403` means the server is down.
+
+---
+
+`401` means the request was malformed while `403` means the resource moved.
+
+---
+
+`401` means the server crashed while `403` means the request timed out.
+
+#### --answer--
+
+`401` means authentication is required while `403` means authenticated but does not have permission.
+
+### --question--
+
+#### --text--
+
+Which status code means the server is temporarily overloaded or down for maintenance?
+
+#### --distractors--
+
+`500`
+
+---
+
+`502`
+
+---
+
+`301`
+
+#### --answer--
+
+`503`
+
+### --question--
+
+#### --text--
+
+What does `res.status(200).json({ message: "Success" })` do in Express?
+
+#### --distractors--
+
+Sends a `200` response with a plain text message.
+
+---
+
+Sends a `200` response with no body.
+
+---
+
+Redirects the client to the success page.
+
+#### --answer--
+
+Sends a `200` response with a JSON body.
+
+### --question--
+
+#### --text--
+
+What makes Express recognize a middleware function as an error handler?
+
+#### --distractors--
+
+It is placed at the top of the middleware stack.
+
+---
+
+It uses `res.error()` instead of `res.send()`.
+
+---
+
+It is defined inside a route handler.
+
+#### --answer--
+
+It has the parameters `err`, `req`, `res`, and `next`.
+
+### --question--
+
+#### --text--
+
+Where should error-handling middleware be placed in an Express app?
+
+#### --distractors--
+
+Before all route definitions.
+
+---
+
+At the very top of the file, before any imports.
+
+---
+
+Inside the first route handler that might throw an error.
+
+#### --answer--
+
+At the end of the middleware stack, after all routes.
+
+### --question--
+
+#### --text--
+
+In Express 4, what must you do to handle async errors in a route handler?
+
+#### --distractors--
+
+Throw the error directly from the route handler and let Node.js handle it at the process level.
+
+---
+
+Return the error object as a JSON response body with a 500 status code.
+
+---
+
+Use `process.on('uncaughtException')` to catch all unhandled async errors globally.
+
+#### --answer--
+
+Wrap async logic in `try/catch` and call `next(err)` to forward the error to the error handler.
+
+### --question--
+
+#### --text--
+
+What is the purpose of an `asyncHandler` wrapper function in Express 4?
+
+#### --distractors--
+
+It converts synchronous route handlers into asynchronous ones automatically.
+
+---
+
+It automatically restarts the server and clears state when an error occurs.
+
+---
+
+It replaces the error-handling middleware placed at the end of the middleware stack.
+
+#### --answer--
+
+It avoids repeating `try/catch` in every route by forwarding rejected promises to `next`.
+
+### --question--
+
+#### --text--
+
+How does Express 5 handle async errors differently from Express 4?
+
+#### --distractors--
+
+Express 5 requires adding a global `process.on('unhandledRejection')` listener to catch async errors.
+
+---
+
+Express 5 silently ignores async errors and only logs them to the console without stopping the app.
+
+---
+
+Express 5 requires every async route to define its own dedicated error-handling middleware function.
+
+#### --answer--
+
+Express 5 automatically forwards async errors and rejected promises to the error handler without needing `next(err)`.
+
+### --question--
+
+#### --text--
+
+Where should a `404` catch-all middleware be placed in an Express app?
+
+#### --distractors--
+
+Before all other routes, at the top of the file.
+
+---
+
+Inside the error-handling middleware, as a fallback check.
+
+---
+
+At the very end, after the error-handling middleware.
+
+#### --answer--
+
+After all routes but before the error-handling middleware.
+
+### --question--
+
+#### --text--
+
+Which of the following is a best practice for error handling in production Express apps?
+
+#### --distractors--
+
+Always send the full stack trace to the client for easier debugging.
+
+---
+
+Place error-handling middleware before your routes for faster processing.
+
+---
+
+Handle all errors, including 404s, inside a single middleware function.
+
+#### --answer--
+
+Log error details internally and return a user-friendly message instead of sending stack traces to users.
+
+### --question--
+
+#### --text--
+
+How do you enable all of Express built-in debug messages when starting your app?
+
+#### --distractors--
+
+Pass `{ debug: true }` to the `express()` constructor.
+
+---
+
+Call `app.enable('debug')` before defining routes.
+
+---
+
+Add `require('express-debug')` at the top of your entry file.
+
+#### --answer--
+
+Set the `DEBUG` environment variable to `express:*` when running the app.
+
+### --question--
+
+#### --text--
+
+What does `DEBUG=express:router node index.js` do?
+
+#### --distractors--
+
+Enables all Express debug output, including middleware, routing, and application-level events.
+
+---
+
+Disables all debug output entirely and runs the app in silent production mode.
+
+---
+
+Logs only incoming HTTP request details like method and URL to the terminal.
+
+#### --answer--
+
+Shows only router-related debug output, filtering out other Express namespaces.
+
+### --question--
+
+#### --text--
+
+What is `morgan` used for in an Express application?
+
+#### --distractors--
+
+Automatically catching and forwarding async errors in Express route handlers to `next`.
+
+---
+
+Serving static files from a specified directory without defining individual routes.
+
+---
+
+Connecting Express to a relational database and logging all executed queries.
+
+#### --answer--
+
+Logging HTTP requests with details like method, URL, status code, and response time.
+
+### --question--
+
+#### --text--
+
+What is the purpose of a health check route in an Express app?
+
+#### --distractors--
+
+To automatically restart the server and reroute traffic when incoming request volume is too high.
+
+---
+
+To record and forward all incoming HTTP requests to an external monitoring or analytics service.
+
+---
+
+To inspect and block requests from IP addresses that are not on an approved allow-list.
+
+#### --answer--
+
+To report whether the app is running correctly so load balancers and orchestrators can decide if the service is healthy.
+
+### --question--
+
+#### --text--
+
+What does the `SIGTERM` signal tell a Node.js process to do?
+
+#### --distractors--
+
+Restart immediately, clear all in-memory state, and re-initialize all active connections.
+
+---
+
+Dump a full memory snapshot to disk for later analysis and debugging purposes.
+
+---
+
+Force-kill all active database connections and close all open file descriptors right away.
+
+#### --answer--
+
+Begin shutting down, giving the app a chance to finish existing work before exiting.
+
+### --question--
+
+#### --text--
+
+What does calling `server.close()` do during a graceful shutdown?
+
+#### --distractors--
+
+Immediately terminates all active connections and exits the process.
+
+---
+
+Sends a 500 response to any clients currently connected.
+
+---
+
+Deletes all in-memory session data and restarts the server.
+
+#### --answer--
+
+Stops accepting new connections while allowing existing ones to finish.
+
+### --question--
+
+#### --text--
+
+Why would you return a 503 status from your health check route during a graceful shutdown?
+
+#### --distractors--
+
+To log the shutdown event and timestamp to an external monitoring dashboard for audit purposes.
+
+---
+
+To force the orchestrator to immediately spin up a new replacement instance before shutdown completes.
+
+---
+
+To notify all currently connected clients that their active sessions have been saved successfully.
+
+#### --answer--
+
+To signal to the load balancer that the app is unavailable so it stops routing new traffic to it.
@@ -0,0 +1,13 @@
+{
+  "isUpcomingChange": true,
+  "dashedName": "quiz-error-handling-in-express",
+  "blockLabel": "quiz",
+  "blockLayout": "link",
+  "helpCategory": "Backend Development",
+  "challengeOrder": [
+    {
+      "id": "6a04bbc9815e737ed711622e",
+      "title": "Error Handling in Express Quiz"
+    }
+  ]
+}
@@ -62,7 +62,10 @@
        {
          "dashedName": "error-handling-in-express",
          "comingSoon": true,
-          "blocks": ["lecture-understanding-error-handling-and-health-checks"]
+          "blocks": [
+            "lecture-understanding-error-handling-and-health-checks",
+            "quiz-error-handling-in-express"
+          ]
        },
        { "dashedName": "websockets", "comingSoon": true, "blocks": [] },
        { "dashedName": "node-and-sql", "comingSoon": true, "blocks": [] },