React JS - Java Programmer

Programming Question Of React Js

1. Create a functional component that displays “Hello, World!” on the screen import React from ‘react’; const HelloWorld = () => { return Hello, World!; }; export default HelloWorld; 2. Create a counter component that increments and decrements the count on button clicks import React, { useState } from ‘react’; const Counter = () => … Read more

Interview Questions of React JS

1. What is React? Answer:React is a JavaScript library for building user interfaces, maintained by Facebook. It allows developers to create large web applications that can update and render efficiently in response to data changes. 2. What are the features of React? Answer: JSX, Components, Virtual DOM, One-way Data Binding, and Performance. 3. What is … Read more

Code Splitting and Lazy Loading

Code Splitting and Lazy Loading are powerful techniques in web development that help improve the performance and load time of web applications by dividing code into smaller chunks and loading them only when needed. Code Splitting Code Splitting refers to the process of breaking up your application’s code into smaller bundles that can be loaded … Read more

Render Props

Render props is a pattern in React that allows you to share code between components using a prop whose value is a function. This function receives props from the parent component and returns a React element, enabling more flexible and reusable component designs. Basics of Render Props A render prop is a function prop that … Read more

Higher-Order Components (HOCs)

Higher-Order Components (HOCs) are an advanced technique in React for reusing component logic. They are not a part of the React API but a pattern that emerges from React’s compositional nature. What is a Higher-Order Component? A Higher-Order Component is a function that takes a component and returns a new component. HOCs are used to … Read more

Advanced Topics

React Hooks Custom Hooks: Building reusable logic encapsulated in hooks. useRef and useImperativeHandle: Managing and interacting with refs. useContext and useReducer: Context API with reducers for state management. Performance Optimization Memoization: Using React.memo, useMemo, and useCallback to prevent unnecessary re-renders. Virtualization: Rendering only the visible portion of large lists with libraries like react-window or react-virtualized. … Read more

Using Jest and Enzyme

To get started with testing using Jest and Enzyme in a React project, follow these steps Setting Up Jest and Enzyme Step 1: Install Dependencies First, ensure you have Jest, Enzyme, and the necessary adapters installed. If you’re using React 16, the command would be: npm install –save-dev jest enzyme enzyme-adapter-react-16 For React 17, replace … Read more

Testing React Components

Testing React components is an essential part of ensuring your application works as expected and helps catch bugs early in the development process. There are various tools and libraries available for testing React components, each serving different purposes. Types of Testing Unit Testing: Tests individual components or functions in isolation. Integration Testing: Tests how components … Read more

Testing In React

First, make sure you have Jest and React Testing Library installed in your project. You can install them using npm or yarn npm install –save-dev jest @testing-library/react @testing-library/jest-dom Sample React Component Let’s create a simple React component that we can test Button.js import React from ‘react’; const Button = ({ onClick, label }) => ( … Read more

Using Styled-Components

Styled-components is a popular library for styling React components using tagged template literals, which allows you to write plain CSS in your JavaScript files. Here’s how to use styled-components in a React project Installation First, you need to install the styled-components library npm install styled-components Basic Usage Create styled components by importing the styled object … Read more