TCS React Js Frontend Developer Interview Questions, Process, and Tips

JSX is a syntax extension for JavaScript used in React to write HTML-like code in JavaScript.

• JSX allows developers to write HTML-like code in JavaScript

• It is not a separate language, but a syntax extension for JavaScript

• JSX code is compiled into JavaScript code by Babel

• JSX expressions must have a single parent element

• JSX expressions can include JavaScript expressions using curly braces {}

State and Props are two important concepts in React for managing data and passing data between components.

• State is an object that holds data that can change over time within a component.

• Props are read-only data that are passed from a parent component to a child component.

• State can be updated using setState() method.

• Props can be accessed using this.props.

• State is used for managing component's internal state while props ...read more

To update state in React components, use setState() method.

• Use setState() method to update state

• Pass an object with updated state values to setState()

• setState() is asynchronous, so use callback function to perform actions after state update

• Avoid directly modifying state using this.state

• Example: this.setState({ count: this.state.count + 1 }, () => console.log('State updated'))

Question about React basics, states, props, components, hooks, and API.

• React is a JavaScript library for building user interfaces.

• States and props are used to manage data in React components.

• Components are reusable building blocks for UI.

• Hooks are functions that add functionality to functional components.

• APIs are used to fetch data from external sources.

• Examples: useState, useEffect, axios, fetch.

Components can be created as classes or functions in React JS.

• Class components are created using ES6 classes and have a state and lifecycle methods.

• Function components are created using functions and do not have a state or lifecycle methods.

• Hooks can be used in function components to add state and lifecycle functionality.

• Components can be reused throughout the application.

• Examples: Class component - class MyComponent e...read more

Hooks are a feature in React that allow for stateful logic to be used in functional components.

• Hooks allow for reusable logic to be extracted from components

• They simplify code and reduce the need for class components

• useState hook allows for state management in functional components

• useEffect hook allows for side effects to be performed in functional components

• useContext hook allows for easy access to context in function