Introduction

One should always keep updated from the latest trends and new concerns on the technology for the market growth. Recently a web platform is well booming which is React JS because of its simple to use and much informative as well.

A front-end JavaScript toolkit for building user interfaces based on UI elements that is open-source and free. Meta, together with a number of unaffiliated programmers and companies, keep it updated. Since its debut in May 2013, React has emerged as the most popular front end for web development.

Developers found the answer they were seeking for with React JS. It employs JSX, a special syntax that enables the application of HTML tag syntax and HTML quotes for generating particular sub components. This is highly beneficial in supporting the development of machine-readable programme even while compounding components into a single- time verified file.The future of developers are mostly visioned with React JS as it has highly used by the developers. As per the survey approx 8787 Industries had implemented with React JS

Aspects (Features)

Virtual DOM

React treats every element as a component, whether it is a class component or a functional component.State may exist within a component. Simply explained, whenever the state of any component is updated, react changes its Virtual DOM tree. This happens each time we make a modification to our JSX file. Although it would appear to be inefficient, updating the virtual DOM doesn't need much time, therefore the cost is not really substantial. At any given time, React keeps two Virtual DOMs, one of which is the updated Virtual DOM and the other of which is simply the pre-update version of the updated Virtual DOM. In order to determine what specific changes have been made to the DOM, such as which components have changed, it now compares the pre-update version with the updated Virtual DOM. This procedure of comparison between the current Virtual DOM tree and the previous one is known as ‘diffing’. React updates only those objects on the real DOM once it determines precisely what has changed. Updates to the real DOM are made using batch updates in React. It simply means that batches of changes to the real DOM are transmitted rather than a single update for every time a component's state changes. React accomplishes this most effectively by guaranteeing that the Real DOM receives batch changes to re-render the UI. As we've seen, re-rendering the user interface is the most expensive component of the process. This entire process of translating updates to the real DOM is called Reconciliation

Unidirectional Data Flow

Data can move in only one pathway on transferring the different parts of program with React the data from parent is called Prop where you can transfer data only with prop to child components on which child components cannot update or modify on their own they must clean the data flow better. Thus, it only affect the child component not to prop

• Debugging is much simpler when there is one-way data flow. The developer can conduct a more effective dry run (or employ tools) when they are aware of the data's origin and destination.
• The programme is less likely to include errors and the developer has more control when data only flows in one direction.
• A process is efficient since excess resources are not squandered because the used libraries are aware of the restrictions and requirements of the unidirectional flow.

Composable Components

In contemporary web UI libraries and frameworks, this feature is typical. But it's crucial to bring it up and bear in mind. Reusable components have many advantages for web development, including greater control and cheaper maintenance costs, quicker development to boost productivity and income, faster creation and delivery of applications, and more apps with higher quality in less time.

Server Side Rendering Support

Server Side Rendering, SSR is the capacity of a JavaScript application to render on the server rather than in the browser.

• It is helpful in faster first page loading time
• Helps in easily gathering the metadata if the people are sharing the page on social media
• Search engines cannot correctly and efficiently index applications that only render client-side, which makes it crucial for SEO. Despite Google's most recent indexing advancements, there are still alternative search engines, and Google itself isn't flawless. Additionally, client-side loading is bad for performance because Google likes websites with quick load times.

Companies Website built with the help of React JS

Netflix

Netflix delivers TV shows and movies over the internet to TVs, computers, and mobile devices. People utilize VPNs to get the US version since they are so well-liked. They were among the first companies, founded in 1997, to recognize the existence of online piracy.

To maintain a consistent developer experience across all of Netflix's web pages, which are all server-side rendered React pages that serve the generated HTML before serving the client-side application, it was crucial to maintain the newly optimized homepage's structure.

Salesforce

Salesforce is a global cloud computing company that develops CRM solutions and provides business software on a subscription basis. As being a language React JS has been created by Facebook Meta that makes it easier to create and maintain HTML views in JavaScript. This enables a more modular design when creating a web application that works with Salesforce.

Airbnb

Airbnb which is an online community marketplace allows users to publish, find, and book rooms all around the world. Airbnb have recognized how important mobile was becoming to there business eventually not having much mobile engineers to reach there goals they started to find there alternative options and came up with react from which they built there website. Within Airbnb, it has been a very successful and well-liked web framework.

NPM is a type of Javascript. It has been a great tool for developers since they can share the prepared code for resolving any bugs within a particular website or application.

Here are some most used NPM packages in Node Js :

1. Lodash

Lodash is particularly useful if you’re working with lots of numbers, digits, arrays, etc.

People, who find JavaScript a challenging language, can also go for Lodash. The creation of complex functions is also easier with Lodash.

The best thing about Lodash is that it is available for usage in different formats and packages. That way, web developers can use this NPM package with greater flexibility.

Lodash is a utility library that makes JavaScript easier by taking the hassle out of working with arrays, numbers, objects, strings, etc.

2. Socket.io 

Socket.IO is a library that enables real-time, bidirectional and event-based communication between the browser and the server.

A real-time application (RTA) is an application that functions within a period that the user senses as immediate or current.

Some examples of real-time applications are –

•  Instant messengers − Chat apps like Whatsapp, Facebook Messenger, etc. You need not refresh your app/website to receive new messages.
•   Push Notifications − When someone tags you in a picture on Facebook, you receive a notification instantly.
• Collaboration Applications − Apps like google docs, which allow multiple people to update same documents simultaneously and apply changes to all people's instances.
• Online Gaming − Games like Counter Strike, Call of Duty, etc., are also some examples of real-time applications.

3. Nodemailer

Nodemailer is a Node. js module that allows you to send emails from your server with ease. Whether you want to communicate with your users or just notify yourself when something has gone wrong, one of the options for doing so is through mail.

It is useful for below resons:

Zero dependencies on other modules

• Secure emails delivery
• HTML content or embedded attachments
• Unicode support
• Various transport options besides

4. Pug

Pug is a template engine for Node and for the browserIt compiles to HTML and has a simplified syntax, which can make you more productive and your code more readable. Pug makes it easy both to write reusable HTML, as well as to render data pulled from a database or API.

Pug is a templating language. Pug has powerful features like conditions, loops, includes, mixins using which we can render HTML code based on user input or reference data.

It is used to generate HTML. Why not write the HTML directly? For one, Pug requires a lot less typing. More importantly, as a templating language, Pug has many features that HTML does not, such as simple coding constructions like conditional and case statements. It also has the ability to import other files, allowing reuse of sections of code, which is not possible in HTML directly.

5. Mocha

Mocha is a testing library for Node.js, created to be a simple, extensible, and fast.

It's one of the simplest test suites for Node.Js available and allows for fairly accurate reporting, asynchronous tests, test coverage reports and, most importantly, can use any assertion library.

It also cleans the state of the software being tested to ensure that test cases run independently of each other.

While it can be used with most assertion libraries, Mocha.js is commonly used with Chai, a popular assertion library for Node.js and the browser.

Mocha.js makes provision for creating test hooks. Hooks are basically logic that have been configured to run before or after tests. They are useful for setting up preconditions for tests or cleaning up resources after tests.

6. Passport

Passport is middleware for Node.js that makes it easy to implement authentication and authorization. Whether you are building your first login page or are an expert in all things identity, the documentation will help you understand Passport and use it in your applications.

Passport uses the concept of strategies to authenticate requests. Strategies can range from verifying username and password credentials, delegated authentication using Oauth (for example, via Facebook or Twitter ), or federated authentication using OpenID .

Before authenticating requests, the strategy (or strategies) used by an application must be configured.

7. Moment-Luxon

Luxon is a library for working with dates and times in JavaScript. Luxon can be thought of as the evolution of Moment.

•  A nice API for working with datetimes
• Interval support (from time x to time y)
• Duration support (14 days, 5 minutes, 33 seconds)
• Parsing and Formatting datetimes, intervals, and durations
•  Internationalization of strings using the Intl API
•  Detailed and unambiguous math operations
• Built-in handling of time zones
• Partial support for multiple calendar systems

8. Yup

Yup is a JavaScript schema builder for value parsing and validation. Define a schema, transform a value to match, validate the shape of an existing value, or both. Yup schema are extremely expressive and allow modeling complex, interdependent validations, or value transformations.

Yup separates the parsing and validating functions into separate steps. Cast() transforms data while validate checks that the input is the correct shape. Each can be performed together (such as HTML form validation) or seperately (such as deserializing trusted data from APIs).

9. JSHint

JSHint is a community-driven tool that detects errors and potential problems in JavaScript code. Since JSHint is so flexible, you can easily adjust it in the environment you expect your code to execute.

JSHint is an open source tool which detects errors and potential problems in JavaScript code.

To lint your JavaScript you have two options.

1.             Go to JSHint.com and paste your code in there on line text editor.

2.             Install JSHint in your IDE.

-      Atom: linter-jshint (must have Linter plugin installed)

-      Sublime Text: JSHint Gutter and/or Sublime Linter

-      Vim: jshint.vim or jshint2.vim

-      Visual Studio: VSCode JSHint

10. Underscore

Underscore. js is a utility library that is widely used to deal with arrays, collections and objects in JavaScript. It can be used in both frontend and backend based JavaScript applications. Usages of this library include filtering from array, mapping objects, extending objects, operating with functions and more.

11. Bower.io

 Managing utilities can rapidly become overwhelming, Bower makes sure you stay in control by managing components. It categorizes every packages you are using, runs constant checks for any potential risks and helps in updating as well.

Bower is optimized for the front-end. If multiple packages depend on a package - jQuery for example - Bower will download jQuery just once. This is known as a flat dependency graph and it helps reduce page load.

You can declare variables in JavaScript in 3 ways, by utilising the const, let, and var keyword. Each type of variable behaves differently during the processes of declaration, initialization, value access, and assignment. Lets brief into the difference and scopes. You can strengthen your understanding of JavaScript variables by reading this article, so let's get started.

var

let

const