D277 ITSW 2131 Front End Web
Development
Objective Assessment Review
(Questions & Solutions)
2025
©2025
, Multiple Choice Questions
1. Question 1
In a React-based application, what is the primary advantage of using
the Virtual DOM?
A. It enables direct manipulation of the browser’s DOM for maximum
control.
B. It provides an efficient diffing and update mechanism that
minimizes re-rendering.
C. It compiles JavaScript into optimized machine code.
D. It enhances network communication speed.
ANS: B
Rationale: The Virtual DOM allows React to compute the minimal set
of changes to update the real DOM, which results in improved
performance and efficiency when rendering dynamic UIs.
2. Question 2
When deploying an Angular application with Ahead-of-Time (AOT)
compilation, what key benefit is achieved in production?
A. Enhanced runtime type checking.
B. Reduced bundle size and faster load times due to pre-compilation
of templates.
C. Increased support for older browsers through polyfills.
D. Dynamic injection of dependencies at runtime.
ANS: B
Rationale: AOT compiles Angular templates during the build phase
rather than at runtime, which reduces the bundle size and accelerates
the initial load performance.
3. Question 3
Which of the following best describes the function of code splitting in a
Single Page Application (SPA)?
A. Bundling all code into a single file to minimize HTTP requests.
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, B. Dynamically loading portions of code on demand to improve
performance.
C. Integrating CSS and JavaScript into one package.
D. Preloading all assets before any render takes place.
ANS: B
Rationale: Code splitting breaks down the application bundle into
smaller chunks that are loaded as needed, which helps reduce the initial
load time and improves overall performance.
4. Question 4
In a Progressive Web App (PWA), what is the primary role of Service
Workers?
A. Encrypting all network communications.
B. Providing offline functionality and caching assets to enhance user
experience.
C. Monitoring user behavior for targeted advertising.
D. Handling server-side authentication protocols.
ANS: B
Rationale: Service Workers intercept network requests to cache
resources, enabling offline access and faster retrieval of assets in
subsequent visits.
5. Question 5
Which stage in the browser’s rendering pipeline is responsible for
recalculating styles and determining layout before painting?
A. HTML Parsing.
B. Style Recalculation.
C. JavaScript Execution.
D. Compositing.
ANS: B
Rationale: After the HTML is parsed, the browser recalculates styles
and layouts, updating the Render Tree before the painting phase begins.
6. Question 6
In the context of modern front-end optimization, what does tree
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, shaking achieve during bundling?
A. Compressing image assets for faster download.
B. Removing unused code from the final production bundle.
C. Converting CSS into JavaScript code automatically.
D. Enabling hot module replacement during development.
ANS: B
Rationale: Tree shaking analyzes module dependencies to eliminate
code that is not referenced, thereby reducing the final bundle size and
improving load times.
7. Question 7
In handling asynchronous operations within front-end applications,
what is the key role of the event loop in JavaScript?
A. Immediately executing all tasks in a strictly sequential manner.
B. Scheduling and prioritizing asynchronous tasks (e.g., promises,
callbacks) to run when the call stack is clear.
C. Compiling ES6 code to ES5 on the fly.
D. Blocking the execution of synchronous code until asynchronous
tasks finish.
ANS: B
Rationale: The event loop is central to JavaScript’s concurrency
model—it monitors the call stack and moves tasks from queues to
execution when the stack is empty, managing both microtasks and
macrotasks efficiently.
8. Question 8
Which of the following is a significant advantage of using CSS Grid in
modern web layouts compared to Flexbox?
A. Grid layouts offer two-dimensional control (rows and columns) for
complex designs.
B. Grid layouts render faster in all browsers.
C. CSS Grid eliminates the need for media queries in responsive
designs.
D. CSS Grid provides built-in animations and transitions.
ANS: A
©2025
Development
Objective Assessment Review
(Questions & Solutions)
2025
©2025
, Multiple Choice Questions
1. Question 1
In a React-based application, what is the primary advantage of using
the Virtual DOM?
A. It enables direct manipulation of the browser’s DOM for maximum
control.
B. It provides an efficient diffing and update mechanism that
minimizes re-rendering.
C. It compiles JavaScript into optimized machine code.
D. It enhances network communication speed.
ANS: B
Rationale: The Virtual DOM allows React to compute the minimal set
of changes to update the real DOM, which results in improved
performance and efficiency when rendering dynamic UIs.
2. Question 2
When deploying an Angular application with Ahead-of-Time (AOT)
compilation, what key benefit is achieved in production?
A. Enhanced runtime type checking.
B. Reduced bundle size and faster load times due to pre-compilation
of templates.
C. Increased support for older browsers through polyfills.
D. Dynamic injection of dependencies at runtime.
ANS: B
Rationale: AOT compiles Angular templates during the build phase
rather than at runtime, which reduces the bundle size and accelerates
the initial load performance.
3. Question 3
Which of the following best describes the function of code splitting in a
Single Page Application (SPA)?
A. Bundling all code into a single file to minimize HTTP requests.
©2025
, B. Dynamically loading portions of code on demand to improve
performance.
C. Integrating CSS and JavaScript into one package.
D. Preloading all assets before any render takes place.
ANS: B
Rationale: Code splitting breaks down the application bundle into
smaller chunks that are loaded as needed, which helps reduce the initial
load time and improves overall performance.
4. Question 4
In a Progressive Web App (PWA), what is the primary role of Service
Workers?
A. Encrypting all network communications.
B. Providing offline functionality and caching assets to enhance user
experience.
C. Monitoring user behavior for targeted advertising.
D. Handling server-side authentication protocols.
ANS: B
Rationale: Service Workers intercept network requests to cache
resources, enabling offline access and faster retrieval of assets in
subsequent visits.
5. Question 5
Which stage in the browser’s rendering pipeline is responsible for
recalculating styles and determining layout before painting?
A. HTML Parsing.
B. Style Recalculation.
C. JavaScript Execution.
D. Compositing.
ANS: B
Rationale: After the HTML is parsed, the browser recalculates styles
and layouts, updating the Render Tree before the painting phase begins.
6. Question 6
In the context of modern front-end optimization, what does tree
©2025
, shaking achieve during bundling?
A. Compressing image assets for faster download.
B. Removing unused code from the final production bundle.
C. Converting CSS into JavaScript code automatically.
D. Enabling hot module replacement during development.
ANS: B
Rationale: Tree shaking analyzes module dependencies to eliminate
code that is not referenced, thereby reducing the final bundle size and
improving load times.
7. Question 7
In handling asynchronous operations within front-end applications,
what is the key role of the event loop in JavaScript?
A. Immediately executing all tasks in a strictly sequential manner.
B. Scheduling and prioritizing asynchronous tasks (e.g., promises,
callbacks) to run when the call stack is clear.
C. Compiling ES6 code to ES5 on the fly.
D. Blocking the execution of synchronous code until asynchronous
tasks finish.
ANS: B
Rationale: The event loop is central to JavaScript’s concurrency
model—it monitors the call stack and moves tasks from queues to
execution when the stack is empty, managing both microtasks and
macrotasks efficiently.
8. Question 8
Which of the following is a significant advantage of using CSS Grid in
modern web layouts compared to Flexbox?
A. Grid layouts offer two-dimensional control (rows and columns) for
complex designs.
B. Grid layouts render faster in all browsers.
C. CSS Grid eliminates the need for media queries in responsive
designs.
D. CSS Grid provides built-in animations and transitions.
ANS: A
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