Top 300 KnockoutJS Multiple Choice Questions (MCQs)

KnockoutJS MCQs and Answers

1. What is KnockoutJS?
A. A JavaScript library for building user interfaces
B. A framework for server-side Node.js applications
C. A library for making AJAX requests
D. A testing framework for JavaScript

Answer: A

2. Which of these is a feature of KnockoutJS?
A. Data binding
B. Server-side templating
C. Database migrations
D. Image processing

Answer: A

3. How does KnockoutJS update the UI when data changes?
A. Using events and callbacks
B. By rerendering the entire page
C. Through dirty checking
D. With a virtual DOM

Answer: C

4. What syntax does KnockoutJS use for its bindings?
A. Bracket notation
B. Curly braces
C. Square brackets
D. Parentheses

Answer: B

5. How can you define a view model in KnockoutJS?
A. As a global variable
B. As an ES6 class
C. By calling ko.viewModel()
D. By calling ko.observable()

Answer: D

6. Which binding links an element’s text to a view model property?
A. The visible binding
B. The css binding
C. The text binding
D. The click binding

Answer: C

7. How do you handle user events in KnockoutJS?
A. With event bindings like click
B. By adding JavaScript event listeners
C. With server-side code
D. In a separate events file

Answer: A

8. What is an observable in KnockoutJS?
A. A variable that can be watched
B. An Array method for notifications
C. An object storing view models
D. A UI component

Answer: A

9. Which binding updates visibility based on a condition?
A. The invisible binding
B. The text binding
C. The css binding
D. The visible binding

Answer: D

10. How do you iterate through collections with KnockoutJS?
A. With the each binding
B. With a for loop
C. Using knockout’s map() method
D. By calling ko.render()

Answer: A

KnockoutJS Multiple Choice Questions

11. What does the MVVM pattern stand for?
A. Model-View-Velocity Module
B. Model-View-Vendor Model
C. Model-View-ViewModel
D. Model-Velocity-ViewModel

Answer: C

12. KnockoutJS uses which design pattern for data binding?
A. Singleton Pattern
B. Factory Pattern
C. Observer Pattern
D. Decorator Pattern

Answer: C

13. Which utility function returns an observable?
A. ko.variable()
B. ko.value()
C. ko.observable()
D. ko.data()

Answer: C

14. How can you write conditional logic in KnockoutJS bindings?
A. With if-else statements
B. Using JavaScript operators like >, < etc.
C. By calling functions
D. With the visible binding

Answer: B

15. What does the click binding allow?
A. Adding click event handlers
B. Changing CSS on click
C. Hiding elements on click
D. Console logging clicks

Answer: A

16. How is scoped CSS implemented in KnockoutJS?
A. With scoped selectors
B. Using the css binding
C. By adding classes with JavaScript
D. With shadow DOM

Answer: B

17. What keyword defines a KnockoutJS component?
A. section
B. component
C. compose
D. import

Answer: B

18. How do you reference observables in bindings?
A. By their name
B. With $parent
C. Using this[]
D. Using $data

Answer: D

19. What can computed observables do?
A. Make AJAX requests
B. Merge other observables
C. Replace observables
D. Store data

Answer: B

20. How does KnockoutJS compare new and old view model states?
A. By comparing JSON
B. Using setInterval
C. With dirty checking
D. By recalculating bindings

Answer: C

21. Which utility parses and stringifies JSON?
A. ko.toJSON()
B. ko.parse()
C. ko.mapping
D. ko.data()

Answer: C

22. What does the checked binding do?
A. Adds checkboxes to the UI
B. Sets checked state for checkboxes and radio buttons
C. Validates forms
D. Handles checkbox clicks

Answer: B

23. How can you configure components in KnockoutJS?
A. With parameters
B. Using JSON
C. With external files
D. By subclassing

Answer: A

24. What does the options binding do?
A. Sets dropdown options
B. Creates JavaScript objects
C. Parses JSON
D. Makes observables

Answer: A

25. How do you select elements in KnockoutJS bindings?

A. By tag name
B. Using jQuery selectors
C. With CSS selectors
D. By ID only

Answer: C

26. Which binding updates inner HTML?
A. invisible binding
B. html binding
C. text binding
D. show binding

Answer: B

27. What keyword subscribes to observables?
A. on
B. listen
C. subscribe
D. notify

Answer: C

28. What is a view model?
A. A UI template
B. A pattern to connect data and UI
C. An observable
D. Part of the virtual DOM

Answer: B

29. How do you nest view models?

A. With MVC containers
B. Using knockout components
C. By subclassing
D. With $parent

Answer: D

30. Which binding sets CSS styles?

A. styles binding
B. visible binding
C. css binding
D. text binding

Answer: C

31. What does the attr binding allow?
A. Updating attributes
B. Reading attributes
C. Adding event handlers
D. Setting inner HTML

Answer: A

32. Which is NOT a KnockoutJS template engine?
A. Underscore
B. Handlebars
C. jQuery
D. Mustache

Answer: A

33. What does the foreach binding do?
A. Loops arrays
B. Makes AJAX requests
C. Accesses child view models
D. Calls callback functions

Answer: A

34. How can you create custom bindings?

A. With ko.binding()
B. By subclassing
C. With AMD modules
D. Using ko.extend()

Answer: D

35. What does the with binding do?

A. Adds child view models
B. Implements scoped CSS
C. Sets execution context
D. Imports other view models

Answer: C

36. Which operator returns observables to initial state?
A. =
B. =
C. null
D. !

Answer: C

37. How do you select component elements?

A. With this[]
B. Using $component
C. By ID only
D. With jQuery selectors

Answer: B

38. What syntax does computed observables use?
A. () => {}
B. get() {}
C. ko.calc()
D. func() {}

Answer: B

39. Which method runs code when an observable changes?

A. subscribe()
B. on()
C. notify()
D. listen()

Answer: A

40. What utility tracks model changes?
A. ko.view()
B. ko.input()
C. ko.mapping
D. ko.bind()

Answer: C

41. How can you write asynchronous computed observables?

A. With promises
B. Using await
C. With AJAX requests
D. By calling next()

Answer: B

42. Which operator sets observables to default value?

A. =
B. =*
C. null
D. ||

Answer: D

43. How do you group observables into objects?
A. With {} literals
B. By calling ko.group()
C. Using factory functions
D. With the section binding

Answer: A

44. What is responsible for linking view models?
A. Routing
B. Templating
C. Data binding
D. Declarative bindings

Answer: C

45. What does the template binding do?
A. Sets view templates
B. Creates UI components
C. Implements MVC pattern
D. Handles events

Answer: A

46. How can you dynamically add/remove bindings?
A. Using knockout lifecycle methods
B. With jQuery
C. By calling ko.apply()
D. Using native DOM methods

Answer: D

47. Which binding shows/hides elements?
A. visible
B. if
C. show
D. toggle

Answer: A

48. What does the click binding create?
A. Event handler functions
B. Click event listeners
C. Button elements
D. Console logs

Answer: B

49. How do you register components?
A. With ko.component()
B. Using tags
C. Inside $(document).ready()
D. By inheriting components

Answer: A

50. Which operator updates view models from observables?
A. <- B. =>
C. >>
D. <<

Answer: A

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