ReactJS tutorial provides basic and advanced concepts of ReactJS. Currently, ReactJS is one of the most popular JavaScript front-end libraries which has a strong foundation and a large community.
ReactJS is a declarative, efficient, and flexible JavaScript library for building reusable UI components. It is an open-source, component-based front end library which is responsible only for the view layer of the application. It was initially developed and maintained by Facebook and later used in its products like WhatsApp & Instagram.

Why we use ReactJS?

The main objective of ReactJS is to develop User Interfaces (UI) that improves the speed of the apps. It uses virtual DOM (JavaScript object), which improves the performance of the app. The JavaScript virtual DOM is faster than the regular DOM. We can use ReactJS on the client and server-side as well as with other frameworks. It uses component and data patterns that improve readability and helps to maintain larger apps.

Prerequisite

Before learning ReactJS in-depth, you must have a good knowledge of JavaScript, HTML5, and CSS. The knowledge of ECMAScript 2015 syntax can also be helpful.

React Introduction

ReactJS is a declarative, efficient, and flexible JavaScript library for building reusable UI components. It is an open-source, component-based front end library responsible only for the view layer of the application. It was created by Jordan Walke, who was a software engineer at Facebook. It was initially developed and maintained by Facebook and was later used in its products like WhatsApp & Instagram. Facebook developed ReactJS in 2011 in its newsfeed section, but it was released to the public in the month of May 2013.
Today, most of the websites are built using MVC (model view controller) architecture. In MVC architecture, React is the ‘V’ which stands for view, whereas the architecture is provided by the Redux or Flux.
A ReactJS application is made up of multiple components, each component responsible for outputting a small, reusable piece of HTML code. The components are the heart of all React applications. These Components can be nested with other components to allow complex applications to be built of simple building blocks. ReactJS uses virtual DOM based mechanism to fill data in HTML DOM. The virtual DOM works fast as it only changes individual DOM elements instead of reloading complete DOM every time.
To create React app, we write React components that correspond to various elements. We organize these components inside higher level components which define the application structure. For example, we take a form that consists of many elements like input fields, labels, or buttons. We can write each element of the form as React components, and then we combine it into a higher-level component, i.e., the form component itself. The form components would specify the structure of the form along with elements inside of it.

Why learn ReactJS?

Today, many JavaScript frameworks are available in the market(like angular, node), but still, React came into the market and gained popularity amongst them. The previous frameworks follow the traditional data flow structure, which uses the DOM (Document Object Model). DOM is an object which is created by the browser each time a web page is loaded. It dynamically adds or removes the data at the back end and when any modifications were done, then each time a new DOM is created for the same page. This repeated creation of DOM makes unnecessary memory wastage and reduces the performance of the application.
Therefore, a new technology ReactJS framework invented which remove this drawback. ReactJS allows you to divide your entire application into various components. ReactJS still used the same traditional data flow, but it is not directly operating on the browser’s Document Object Model (DOM) immediately; instead, it operates on a virtual DOM. It means rather than manipulating the document in a browser after changes to our data, it resolves changes on a DOM built and run entirely in memory. After the virtual DOM has been updated, React determines what changes made to the actual browser’s DOM. The React Virtual DOM exists entirely in memory and is a representation of the web browser’s DOM. Due to this, when we write a React component, we did not write directly to the DOM; instead, we are writing virtual components that react will turn into the DOM.

React Features

Currently, ReactJS gaining quick popularity as the best JavaScript framework among web developers. It is playing an essential role in the front-end ecosystem. The important features of ReactJS are as following.
• JSX
• Components
• One-way Data Binding
• Virtual DOM
• Simplicity
• Performance
JSX
JSX stands for JavaScript XML. It is a JavaScript syntax extension. Its an XML or HTML like syntax used by ReactJS. This syntax is processed into JavaScript calls of React Framework. It extends the ES6 so that HTML like text can co-exist with JavaScript react code. It is not necessary to use JSX, but it is recommended to use in ReactJS.
Components
ReactJS is all about components. ReactJS application is made up of multiple components, and each component has its own logic and controls. These components can be reusable which help you to maintain the code when working on larger scale projects.
One-way Data Binding
ReactJS is designed in such a manner that follows unidirectional data flow or one-way data binding. The benefits of one-way data binding give you better control throughout the application. If the data flow is in another direction, then it requires additional features. It is because components are supposed to be immutable and the data within them cannot be changed. Flux is a pattern that helps to keep your data unidirectional. This makes the application more flexible that leads to increase efficiency.
Virtual DOM
A virtual DOM object is a representation of the original DOM object. It works like a one-way data binding. Whenever any modifications happen in the web application, the entire UI is re-rendered in virtual DOM representation. Then it checks the difference between the previous DOM representation and new DOM. Once it has done, the real DOM will update only the things that have actually changed. This makes the application faster, and there is no wastage of memory.
Simplicity
ReactJS uses JSX file which makes the application simple and to code as well as understand. We know that ReactJS is a component-based approach which makes the code reusable as your need. This makes it simple to use and learn.
Performance
ReactJS is known to be a great performer. This feature makes it much better than other frameworks out there today. The reason behind this is that it manages a virtual DOM. The DOM is a cross-platform and programming API which deals with HTML, XML or XHTML. The DOM exists entirely in memory. Due to this, when we create a component, we did not write directly to the DOM. Instead, we are writing virtual components that will turn into the DOM leading to smoother and faster performance.
So, this brings us to the end of blog. This Tecklearn ‘Overview of ReactJS and its features’ blog helps you with commonly asked questions if you are looking out for a job in React JS and Front-End Development. If you wish to learn React JS and build a career in Front-End Development domain, then check out our interactive, React.js with Redux Training, that comes with 24*7 support to guide you throughout your learning period.

React.js with Redux Training

About the Course

Tecklearn’s React JS Training Course will help you master the fundamentals of React—an important web framework for developing user interfaces—including JSX, props, state, and events. In this course, you will learn how to build simple components & integrate them into more complex design components. After completing this training, you will be able to build the applications using React concepts such as JSX, Redux, Asynchronous Programming using Redux Saga middleware, Fetch data using GraphQL, perform Testing using Jest, successively Deploy applications using Nginx and Docker plus build Mobile applications using React Native. Accelerate your career as a React.js developer by enrolling into this React.js training.

Why Should you take React.js with Redux Training?

• The average salary for “React Developer” ranges from $100,816 per year to $110,711 per year, based on the role (Front End Developer/Full Stack Developer) – Indeed.com
• React Native Supports Cross-platform Development (iOS and Android), and it can reduce the development effort by almost 50% without compromising quality or productivity
• Currently, React JS is being used by major companies like Walmart, Netflix, and HelloSign.

What you will Learn in this Course?

Introduction to Web Development and React.js
• Fundamentals of React
• Building Blocks of Web Application Development
• Single-page and Multi-page Applications
• Different Client-side Technologies
• MVC Architecture
• Introduction to React
• Installation of React
• JSX and its use case
• DOM
• Virtual DOM and its working
• ECMAScript
• Difference between ES5 and ES6
• NPM Modules

Components, JSX & Props
• React Elements
• Render Function
• Components
• Class Component
• Thinking In Components
• What Is JSX
• JSX Expressions
• Creating Your First Component
• Functional Components

React State Management using Redux
• Need of Redux
• Redux Architecture
• Redux Action
• Redux Reducers
• Redux Store
• Principles of Redux
• Pros of Redux
• NPM Packages required to work with Redux
• More about react-redux package
React & Redux
• The React Redux Node Package
• Provider Component
• Connecting React Components with Redux Store
• Reducer Composition
• Normalization: Points to Keep in Mind When Designing a Redux Store
• Redux Middleware

React Hooks
• Caveat of JavaScript classes.
• Functional components and React hooks
• What are React hooks?
• Basic hooks
• useState() hook
• How to write useState() hook when state variable is an array of objects
• useEffect() hook
• Fetch API data using useEffect() hook
• useContext() hook
• Rules to write React hooks
• Additional hooks
• Custom hooks

Fetch Data using GraphQL
• What is GraphQL?
• Cons of Rest API
• Pros of GraphQL
• Frontend backend communication using GraphQL
• Type system
• GraphQL datatypes
• Modifiers
• Schemas
• GraphiQL tool
• Express framework
• NPM libraries to build server side of GraphQL
• Build a GraphQL API
• Apollo client
• NPM libraries to build client side of GraphQL
• How to setup Apollo client

React Application Testing and Deployment
• Define Jest
• Setup Testing environment
• Add Snapshot testing
• Integrate Test Reducers
• Create Test Components
• Push Application on Git
• Create Docker for React Application

Introduction to React Native
• What is React Native
• Use of JSX elements With React Native
• The anatomy of a React Native application
• React Native installation and setup
• Running the app on Android Simulator and Android Device
• Working with Styles and Layout
• Connecting React Native to Redux

React with Redux Projects

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