React JS Full Course for Beginners to Advanced with Interview Questions in Hindi
React JS is a popular open-source JavaScript library used for building user interfaces, particularly for single-page applications. Developed and maintained by Facebook, React allows developers to create reusable UI components, making the development process more efficient and scalable.
Key Features of React JS:
- Component-Based Architecture: React encourages breaking down the UI into small, reusable components. Each component manages its own state and can be combined to build complex UIs.
- Virtual DOM: React uses a Virtual DOM to improve performance. Instead of updating the actual DOM directly, React updates a virtual representation of the DOM first. This minimizes the number of changes made to the actual DOM, leading to faster updates and smoother user experiences.
- Declarative UI: With React, you describe what you want the UI to look like, and React takes care of updating the DOM to match this description. This makes it easier to reason about and debug the application.
- JSX Syntax: React uses JSX, a syntax extension that allows you to write HTML elements directly within JavaScript. JSX makes the code more readable and easier to understand, as it closely resembles the HTML structure of the UI.
- One-Way Data Binding: React follows a unidirectional data flow, where data moves from parent components to child components. This makes the data flow easier to track and debug.
- Ecosystem and Tools: React has a rich ecosystem of libraries and tools, including React Router for navigation, Redux for state management, and many others.
React is widely used for building modern web applications, including those by companies like Facebook, Instagram, Netflix, and Airbnb.
Before start work on React JS you must have Knowledge about HTML , CSS & JavaScript
Text editor you can use according to you. I will be use VS Code in this tutorial.
How to Install React JS ?
- Download Node JS
- Install React App using npx create-react-app app-name
- Run Application using npm start
- Understanding folder structure
Print first Hello World in React JS
JSX :-
JSX stands for JavaScript XML. It is simply a syntax extension of JavaScript. It allows us to directly write HTML in React (within JavaScript code), Always return single element.
React Fragment:-
Fragments are a way to group a list of children elements without adding extra nodes to the DOM.
className:-
className is an attribute used to define the CSS classes for an HTML element. This is similar to the standard class attribute in HTML, but in JSX (the syntax extension React uses), the class attribute is replaced with className because class is a reserved keyword in JavaScript.
Component:-
Component is a fundamental building block used to create user interfaces. Components are reusable pieces that can be independently developed, tested, and managed. We will also discussed about how to manage nested components in react js.
CSS & Bootstrap with React JS:-
We will use custom CSS & Bootstrap framework in this tutorial.
State & Props in React JS:-
Props are used for passing data from parent to child components. State is used for managing internal component data.
Hooks in React JS:-
Hooks in React JS are special functions that allow you to use state and other React features in function components. Introduced in React 16.8, Hooks enable function components to become more powerful.
How to create Counter App in React JS?
Reusable Component App
API Integration:-
React JS Interview Questions with Answers:-
What is React JS?
React is a free and open-source front-end JavaScript library created and maintained by Facebook for building user interfaces based on UI components.
What is JSX?
JSX stands for JavaScript XML. It is simply a syntax extension of JavaScript. It allows us to directly write HTML in React (within JavaScript code)
What is Hooks?
Hooks allow us to use “hook” into React function component such as state and lifecycle methods. Hooks were added to React in version 16.8.
What is virtual DOM?
React JS keeps a lightweight representation of the real DOM in the memory that is known as the virtual dom.
var vs state in react js?
Use var, let, or const for general-purpose data storage that doesn’t need to trigger UI updates. Use state for data that influences rendering and needs to persist across re-renders in a React component.
Why we priority to map instead of forEach?
Map will return but forEach not return.
What is Babel in react js ?
Babel is a JavaScript compiler that includes the ability to compile JSX into regular JavaScript.
What is prop drilling?
Prop drilling is the unofficial term for passing data through several nested children components.
What is React Fragment in react js? ​
React fragment allows to return multiple elements from a React component without adding extra nodes to the DOM.
What is redux?
Redux is a popular state management library for JavaScript applications.
