React Questions

componentWillUnmount()

constructor()

componentDidUpdate()

componentDidMount()

{ expression }

expression

{{ expression }}

( expression )

To render the component for the first time.

To perform any necessary cleanup operations before a component is removed from the DOM.

To handle user interactions like button clicks.

To update the state based on changes in props.

useEffect combines the functionality of componentDidMount, componentDidUpdate, and componentWillUnmount.

useEffect is only used for data fetching.

useEffect is a replacement for componentDidMount only.

There is no relationship between useEffect and lifecycle methods.

React doesn't provide a way to access the triggering element

By passing the element as an argument to the event handler

Using this keyword inside the event handler

As a property of the event object (e.g., event.target)

To style components

To enforce the data type of props

To handle user events

To manage component state

Using bind in the constructor

Using arrow functions in the render method

Calling addEventListener within the componentDidMount lifecycle method

Both 'Using bind in the constructor' and 'Using arrow functions in the render method'

To automatically submit the form when all fields are filled.

To ensure data integrity and prevent invalid submissions.

To send data to the server for validation.

To style form elements based on user input.

When you need real-time validation and immediate feedback to the user.

When integrating with a third-party library that requires direct access to form elements.

When dealing with a large, complex form where performance optimization is critical.

When you prefer a more imperative approach and direct DOM manipulation.

const Welcome = () => { ... };

function Welcome(props) { ... }

let Welcome = (props) => { ... }

class Welcome extends React.Component { ... }