Which of the following is a common approach for implementing form validation in React?
All of the above.
Using HTML5 form validation attributes.
Utilizing a dedicated form validation library.
Writing custom validation functions within the component.
What does JSX ultimately get transpiled into?
JSON
CSS
HTML
Plain JavaScript
How can you access the original DOM event object in a React event handler?
React doesn't provide access to the original DOM event; it's completely abstracted.
By directly using event.target or event.currentTarget
event.target
event.currentTarget
By using a ref to the DOM element and accessing its event listeners
Through the nativeEvent property of the synthetic event object
nativeEvent
What is the purpose of the componentWillUnmount() lifecycle method?
componentWillUnmount()
To handle user interactions like button clicks.
To update the state based on changes in props.
To render the component for the first time.
To perform any necessary cleanup operations before a component is removed from the DOM.
In JSX, how would you set the 'class' attribute for an element?
How does the useEffect Hook in functional components relate to lifecycle methods in class components?
useEffect
useEffect is only used for data fetching.
There is no relationship between useEffect and lifecycle methods.
useEffect combines the functionality of componentDidMount, componentDidUpdate, and componentWillUnmount.
componentDidMount
componentDidUpdate
componentWillUnmount
useEffect is a replacement for componentDidMount only.
In a class component, how do you update the state?
By modifying this.props object
this.props
By calling this.setState({ new state })
this.setState({ new state })
Using the useState hook
useState
Using this.state = { new state } directly
this.state = { new state }
What is the purpose of PropTypes in React?
To handle user events
To manage component state
To style components
To enforce the data type of props
Why is event binding often necessary in class components?
To prevent default browser behavior for all events
Event binding is not necessary in React; it's an older JavaScript concept.
To ensure that this refers to the correct component instance inside event handlers
this
To allow passing custom arguments to event handlers
What is the correct way to embed a JavaScript expression inside JSX?
{ expression }
expression
{{ expression }}
( expression )