Unit 5: Performance, SEO, and Deployment - Practice Quiz

1 What is the main purpose of image optimization in a web application?

2 Which image format commonly provides efficient compression for modern websites?

3 What type of information is commonly defined using a Metadata API?

4 Which metadata value is normally displayed on a browser tab?

5 What does code splitting do in a web application?

6 What is a common benefit of code splitting?

7 What does lazy loading mean?

8 Which resource is commonly lazy-loaded when it is below the visible part of a page?

9 What does SEO stand for?

10 Which HTML element is most appropriate for the main heading of a page?

11 What is a production build?

12 Which process commonly reduces the size of production JavaScript files?

13 What is an environment variable commonly used for?

14 Which value commonly changes between development and production environments?

15 What is the main role of a deployment platform?

16 Which service is commonly used to deploy modern web applications?

17 What is the purpose of performance monitoring?

18 Which metric measures how long a page takes to become usable?

19 What is the main purpose of error logging?

20 Which information is useful in an error log?

21 A product page displays the same image at widths ranging from 320 px on phones to 1200 px on desktops. Which approach best reduces unnecessary image transfer?

22 A website's Largest Contentful Paint element is a hero image visible immediately after navigation. Which optimization is most appropriate?

23 A Next.js product route must generate a unique title and description from the product identifier. Which implementation is most suitable?

24 A page appears correctly in search results, but social platforms show no preview image when its URL is shared. Which metadata should be added?

25 An analytics dashboard includes a large chart editor used only after the user selects Edit chart. What is the best code-splitting strategy?

26 After route-based code splitting, users notice a short delay when opening a frequently visited settings page. Which technique can reduce the delay without restoring one large bundle?

27 A long article contains twenty photographs, but only the first two are visible when the page loads. Which loading policy is most appropriate?

28 A lazily loaded comments component causes the page footer to jump downward when the component appears. Which change best addresses the problem?

29 An online store exposes the same product through URLs containing different tracking parameters. Which SEO measure best consolidates ranking signals?

30 A recipe page is indexed, but the team wants search engines to better understand ingredients, cooking time, and ratings. What should be added?

31 A React application performs well during local production testing but is slow when tested through the development server. Why should performance be measured using a production build?

32 A production bundle unexpectedly contains a large debugging library that is imported but never used. Which build feature should normally remove it when the package supports static analysis?

33 A frontend needs an API base URL that differs between staging and production. How should the URL normally be configured?

34 A developer stores a database password in a variable prefixed for exposure to browser code. What is the primary problem?

35 A single-page application deployed to static hosting returns a 404 when users refresh /account/settings, although client-side navigation works. What configuration is needed?

36 A team wants every pull request to receive an isolated URL for testing before production deployment. Which platform capability best supports this workflow?

37 Laboratory tests report fast page loads, but users in one geographic region report poor performance. Which monitoring approach would best verify their experience?

38 A page becomes visually complete quickly, but clicking its main button often feels delayed. Which Core Web Vital is most relevant to investigate?

39 A minified production stack trace points to app.8fd3.js, making the original source location difficult to identify. What should the error-monitoring service use?

40 An error report says Request failed but gives no clue which release, route, or user action produced it. Which improvement would make the report most actionable?

41 A product page displays a 2400×1600 hero photograph in a 600px-wide container. The image is above the fold, uses object-fit: cover, and the server supports responsive image transformation. Which implementation most effectively reduces the image's Largest Contentful Paint contribution without reducing visible quality?

42 A responsive site uses an art-directed mobile crop and a different desktop crop of the same editorial image. Which markup best communicates that the source must change with the viewport rather than merely scale?

43 A route renders product metadata from asynchronous database data. The application generates a canonical URL, Open Graph image, and title. Which design best prevents stale metadata when the product slug changes while preserving a stable canonical URL?

44 A site has a localized article at /en/guide and /fr/guide. Search engines are receiving duplicate-content warnings because each page declares only its own canonical URL. Which metadata strategy is most appropriate?

45 A dashboard's initial JavaScript bundle contains a 900KB charting library used only after a user opens an analytics tab. Which change most directly improves the initial route's parse and execution cost?

46 A bundler produces a shared vendor chunk containing nearly every dependency. The application has several rarely visited routes, but each route still downloads this large chunk on first navigation. Which change best targets route-level performance?

47 A page contains a below-the-fold video player and an above-the-fold hero image. Which loading policy is most appropriate?

48 An infinite-scroll feed uses IntersectionObserver, but it repeatedly requests the next page when the sentinel remains visible during a slow network response. What is the most robust fix?

49 A faceted commerce site exposes thousands of URLs through combinations of filters, many containing the same products and no unique search value. Which strategy best controls crawl waste while preserving useful category pages?

50 A JavaScript-rendered article shows a loading shell in the initial HTML, and the article body appears only after client execution. Organic traffic is low despite correct titles and descriptions. Which change most directly improves crawl reliability?

51 A production build passes functional tests, but its JavaScript bundle contains source maps with embedded source content and internal API paths. What is the primary deployment concern?

52 A release changes hashed asset filenames, but the deployment replaces the old assets immediately. Users with an older HTML document then receive 404 responses for its referenced chunks. Which deployment improvement addresses this failure mode?

53 A frontend build exposes variables prefixed for client access. A developer places a database password in one of those variables, assuming the value is protected because the repository is private. What is the correct assessment?

54 A single container image should be promoted from staging to production without rebuilding. The frontend currently embeds the API base URL during compilation. Which architecture best supports this requirement?

55 A globally distributed application has personalized pages that cannot be publicly cached, while its static assets are content-hashed and immutable. Which deployment design gives the best performance and correctness balance?

56 A serverless deployment handles ordinary requests quickly but times out during a large report export. The export performs CPU-intensive work and exceeds the platform's execution limit. Which redesign is most appropriate?

57 A field-monitoring dashboard reports excellent average LCP, but users on slow mobile networks still complain. Which measurement change is most likely to reveal the problem?

58 A release lowers the overall error rate but increases INP for users on low-end devices. Which investigation provides the strongest evidence for a release decision?

59 An error-monitoring service receives a stack trace from a minified production bundle, but the frames are unreadable. Source maps exist locally and contain sensitive source code. Which setup is most appropriate?

60 A client application logs full request payloads and authenticated URLs whenever an exception occurs. Logs are useful for debugging, but they may contain passwords and personal data. What is the best correction?