Quiz for Event Object

Q1: What is the purpose of the event object in React?

A. To define a new component B. To pass props between components C. To handle and provide details about DOM events D. To manage application state

Q2: How can you access the event object in a React event handler?

A. It is passed as a return value B. It is available globally C. It is passed as an argument to the handler D. It must be imported

Q3: Which of the following is true about React's synthetic event object?

A. It wraps the browser's native event B. It replaces the native event completely C. It only works with class components D. It requires external libraries

Q4: How can you prevent the default behavior of an event in React?

A. event.preventDefault() B. event.stop() C. preventDefault(event) D. event.blockDefault()

Q5: Which method is used to stop the event from propagating up the DOM in React?

A. event.stopPropagation() B. event.preventDefault() C. event.terminate() D. event.blockBubble()

Q6: Which property on the event object gives access to the HTML element that triggered the event?

A. event.source B. event.currentElement C. event.target D. event.caller

Q7: What does event.nativeEvent provide access to?

A. The React-specific event B. The original DOM event C. The state object D. Component props

Q8: What happens if you reuse the same event object asynchronously?

A. It returns null B. It throws an error C. It may have been nullified D. It works as usual

Q9: How do you preserve a React event for use in asynchronous code?

A. event.cache() B. event.persist() C. event.save() D. event.hold()

Q10: In which version of React was the event pooling behavior deprecated?

A. 16.8 B. 17 C. 18 D. 15

Q11: Which property of the event object determines if preventDefault was called?

A. event.isDefaultPrevented() B. event.defaultPrevented C. event.prevented D. event.hasDefault()

Q12: What type of event object does React use?

A. Native event object B. jQuery event object C. Synthetic event object D. Custom browser event

Q13: What is event.bubbles in React SyntheticEvent?

A. Boolean indicating if event was stopped B. Indicates if the event bubbles up the DOM C. Indicates default behavior D. True if event is async

Q14: Can you access keyboard key values using the event object?

A. No B. Only in class components C. Yes, via event.key D. Only using native events

Q15: Which property contains the type of event triggered?

A. event.kind B. event.action C. event.type D. event.class

Q16: Which event object property tells you the mouse button clicked?

A. event.which B. event.keyCode C. event.button D. event.ctrlKey

Q17: What does event.clientX return?

A. Distance from top of screen B. Horizontal mouse position within viewport C. Scroll offset X D. Distance from top of document

Q18: Is SyntheticEvent available in functional components?

A. No B. Yes C. Only in class components D. Only with Redux

Q19: Which event is fired when a user changes input text?

A. onKeyUp B. onChange C. onFocus D. onClick

Q20: How do you detect if the Ctrl key was held during an event?

A. event.isCtrl() B. event.ctrl C. event.ctrlKey D. event.commandKey