Publicis Sapient Reactjs Developer Interview Questions and Answers

Splice is used to add/remove elements from an array, while slice is used to extract a portion of an array without modifying the original array.

• Splice modifies the original array, while slice does not.

• Splice can add elements, remove elements, or replace elements in an array.

• Slice returns a new array with the selected elements from the original array.

• Example: const arr = [1, 2, 3, 4, 5]; arr.splice(2, 1); // removes elem...read more

To reverse a string, iterate through the characters and swap them from start to end.

• Create an empty string to store the reversed result.

• Iterate through the characters of the input string from end to start.

• Append each character to the empty string to reverse the order.

• Return the reversed string.

Fragments in React.js are used to group multiple elements without adding an extra node to the DOM.

• Fragments are a way to group multiple elements without using a wrapper element.

• They help in avoiding unnecessary divs in the DOM.

• Fragments can improve performance by reducing the number of DOM nodes.

• They are useful when returning multiple elements from a component's render method.

• Fragments can be written using the

React offers advantages such as virtual DOM for improved performance, reusable components, and easy integration with other libraries.

• Virtual DOM for efficient updates and improved performance

• Reusable components for easier development and maintenance

• Easy integration with other libraries like Redux for state management

• Support for server-side rendering for better SEO performance

Performance optimization in React Js can be achieved through code splitting, memoization, virtualization, and minimizing re-renders.

• Implement code splitting to load only necessary components when needed

• Use memoization techniques like useMemo and useCallback to prevent unnecessary re-renders

• Implement virtualization for long lists or tables to render only visible items

• Minimize re-renders by using shouldComponentUpdate or

useMemo and useCallback are hooks in React used for optimizing performance by memoizing values and functions respectively.

• useMemo is used to memoize the result of a function so that it is only recomputed when its dependencies change.

• useCallback is used to memoize a function instance so that it is not recreated on every render unless its dependencies change.

• Both hooks help in optimizing performance by preventing unneces...read more