What Is React? – Unveil The Magic Of Interactive UI With React

Do you remember how Facebook’s UI or it’s messenger looked a few years back? During that time you had to refresh or reload the entire page for new updates or messages repeatedly. But now it’s no longer required. Today, each time there is a new update or message, a notification will pop up. Clicking on that will then automatically refresh your page and show you the latest updates. So, how exactly does this happen? Well, this is the magic of ReactJS and in this blog, I am going to discuss what is React and why you should go for it. But before we proceed to see what is react, let’s take a look at the topics I will be discussing:

• JavaScript Frameworks
• Why React?
• What Is React?
• A brief history of ReactJS
• Features Of React
• The popularity of ReactJS among developers
• Components
• Virtual DOM
• JSX
• State and Props
• React Hooks
• Conclusion

JavaScript Frameworks

 Following are the major advantages provided by the JavaScript Frameworks:

1. Efficiency: With the use of pre-built patterns and functions, the development of the applications became easy. The projects which used to take months to develop can now be developed in very less time. This increased the efficiency as well as reduced the time and effort involved.
2. Security: As JavaScript is an open source community, its top frameworks have strong security arrangements. Frameworks are supported by these large communities in which, the members and the users can also act as testers. This increases the chances of detecting any kind of backdoor or bug present in the framework. Thus providing better security at less cost.
3. Cost Reduction: JavaScript Frameworks are free for public use as they are open source. So, when we develop a web application using these frameworks, the overall cost of the application is much lesser.

Because of all these advantages, JavaScript frameworks are used heavily for developing web-applications. They have already proved their potential over the past few years. Among them, the most popular ones are React and Angular. “Even though React is young, it is giving a neck to neck competition to Angular”. If you are planning to make a flourishing career in web development, React certification training is the right move for you. Check out the google trend results for React and Angular for past 7 years. 

So, through this blog, we’ll be learning all about ReactJS. But before understanding what is React, you need to understand why we need it in the first place. For more check out this Full Stack development course today.

Why React?

There were so many JavaScript frameworks available in the market but still React came into the picture. Let’s dive little deeper and find out the reason why ReactJS was needed.

The previous frameworks were using a traditional data flow as you can see from the below diagram.

Here, the data is received from various sources like initial data, real-time data and user input data which is passed to the dispatcher. The dispatcher then forwards this data to the store, from where it ultimately comes to the view. Now, the view is the part where you or a user interact with the application. So, whatever you see on the browser as a web page is the view itself.

But, what do you think happens at the back end of the frameworks using this traditional data flow?

Each time new data is added or any data is updated at the back end, the browser reloads the web page and repeats the whole process again. Only after this, we can see the updated data on the view. But this traditional data flow has one major drawback, it uses the DOM (Document Object Model). DOM is an object that is created by the browser each time a web page is loaded which can dynamically add or remove the data at the back end. But each time any modifications were done a new DOM is created for the same page. This repeated creation of DOM results in unnecessary memory wastage and a decrease in applications performance. React JS is in high demand among all other Web developer training Courses in India and the United States.

Moreover, manipulating DOM was very expensive. Therefore, there was a search for new technology which could save us from this trouble. This is where ReactJS comes to our rescue. With ReactJS, you can divide your entire application into various independent components. ReactJS applications still used the same traditional data flow, but something changed at the back end. Below diagram shows exactly what was going on at the back end.

Now, each time any data is added or updated from the back end, ReactJS uses a new tactic to deal with it. Instead of reloading the entire page, what React does is, it just destroys the old view. Afterward, it renders the view components with updates or new data and then places the new view in place of the old one. As a solution to the memory wastage due to DOM, React introduced Virtual DOM. You might be curious about what is this virtual DOM and how it solves our problem? Don’t worry, I’ll be explaining that later in this blog in detail, but for now, let’s understand what is React.

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What Is React?

React is a component-based library which is used to develop interactive UI’s (User Interfaces). It is currently one of the most popular JavaScript front-end libraries which has a strong foundation and a large community supporting it. 

NOTE: ReactJS is only a frontend library and not the whole framework, which deals with the View component of MVC (Model – View – Controller).

In ReactJS, everything is a component. Consider one lego house as an entire application. Then compare each of the lego blocks to a component which acts as a building block. These blocks/ components are integrated together to build one bigger and dynamic application.

The biggest advantage of using components is that you can change any component at any point in time without affecting the rest of the applications. This feature is most effective when implemented with larger and real-time applications where data changes frequently. Each time any data is added or updated, ReactJS automatically updates the specific component whose state has actually changed. This saves the browser from the task of reloading the whole application to reflect the changes.

ReactJS was developed by Jordan Walke, a software engineer working at Facebook. Facebook implemented ReactJS in 2011 in its newsfeed section, but it was released to the public in May 2013. After the implementation of ReactJS, Facebook’s UI underwent drastic improvement. This resulted in satisfied users and a sudden boost in its popularity.

A brief history of ReactJS

2011: Jordan Walke and Adam Abramov, two Facebook developers, begin developing a new method for creating user interfaces for the social network

2013: Facebook formally introduces ReactJS, which is originally utilised for the news feed functionality.

2015: ReactJS was released as a free source

2016:  ReactJS become a top-starred project on GitHub, further enhancing its appeal to programmers.

2017: The most widely used JavaScript library for front-end development in 2017 is ReactJS.

2018: ReactJS now has new features like React Hooks that make it even simpler to use

2019: ReactJS releases React 16.8, a stable version with bug fixes and enhanced performance.

2020: ReactJS use for web apps is on the rise, with several significant businesses and organisations.

2021: ReactJS released React 17, its most recent stable version, with enhanced server-side rendering features and compatibility.

With a sizable and active developer community working continuously to enhance and grow the library, ReactJS is still one of the most well-liked and extensively used front-end development frameworks available today.

Features Of React

Now that you have understood what is React and why it is used, lets now uncover few of its intriguing features.

1. 1. JSX: JSX stands for JavaScript XML. Its an XML/ HTML like syntax used by React. It extends the ECMAScript so that XML/ HTML like text can co-exist along with JavaScript react code. This syntax is used by the pre-processors like Babel to transform HTML like text found in JavaScript files into standard JavaScript objects. With JSX, we can go a step further by again embedding the HTML code inside the JavaScript. This makes HTML codes easy to understand and boosts JavaScript’s performance while making our application robust.
      
      Let’s see how to write Hello World Program using JSX.
      script.jsx
      

      var MyComponent = React.createClass({
          render :function () {
                      return(    
                      <h2>Hello World</h2>
              );
          }
      });
      
      ReactDOM.render(
         <MyComponent/>, document.getElementById('content')
      );

   2. Virtual DOM: Like an actual DOM, virtual DOM is also a node tree that lists the elements and their attributes and content as Objects and their properties. React’s render function creates a node tree out of the React components. Then, it updates this tree in response to the mutations in data model caused by various actions done either by the user or by the system.

      This virtual DOM works in three simple steps.

      1. 1. Whenever any underlying data changes, the entire UI is re-rendered in Virtual DOM representation.
            
         2. Then the difference between the previous DOM representation and the new one is calculated.
            
            
         3. Once the calculations are done, the real DOM will be updated with only the things that have actually changed. You can think of it as a patch. As patches are applied only to the affected area, similarly, the virtual DOM acts as patches and are applied to the elements which are updated or changed, in the real DOM.

       

      This makes our application faster and there is no memory wastage.

   3. Testability: React views can be used as functions of the state (state is an object which determines how a component will render and behave). Thus, we can easily manipulate with state of the components which we pass to the ReactJS view and take a look at the output and triggered actions, events, functions, etc. This makes React applications quite easy to test and debug.
   4. Server-Side Rendering(SSR): Server-Side rendering allows you to pre-render the initial state of your react components at the server side only. With SSR, the server’s response to the browser becomes only the HTML of the page which is now ready to be rendered. Thus, the browser can now start rendering without having to wait for all the JavaScript to be loaded and executed. As a result, the webpage loads faster. Here the user will be able to see the web page in spite of React still downloading the JavaScript, creating the virtual DOM, linking events, etc. at the back end.
      
   5. One-Way Data Binding: Unlike other frameworks, ReactJS follows unidirectional data flow or one-way data binding. The major advantage of One-Way-Data binding is that throughout the application the data flows in a single direction which gives you better control over it. Because of this, application’s state is contained in specific stores and as a result, rest of the components remains loosely coupled. This makes our application more flexible leading to increased efficiency.
      
   6. Simplicity: Use of JSX files makes the application really simple and
      easy to code as well as understand. Even though we can use plain JavaScript here, using JSX is easier. React’s component-based approach along with distinct lifecycle methods also make it simple to learn.

1. Learning Curve: Learning curve of React is quite low as compared to other frameworks. Anyone having even basic knowledge of programming can easily learn React. So, if you have previous knowledge of HTML and JavaScript you can get your hands on it very quickly.
   

The popularity of ReactJS among developers

With valid reason, ReactJS has grown tremendously popular among developers. Even the most complicated apps are easy to manage and maintain because to its component-based approach to UI development. ReactJS is the finest way to build high-speed web apps since it dramatically boosts performance when components are rendered using a virtual DOM.

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The sizeable and supportive developer community that has embraced ReactJS is another factor in its appeal to programmers. This community offers a multitude of tutorials, articles, and forums that assist developers in learning and honing their library abilities.

All sizes of businesses and organisations, from start-ups to major multinationals, utilise ReactJS on a regular basis. That’s because it helps handle complex web apps and is well-liked by programmers, making it simpler for businesses to locate skilled programmers who are familiar with the library.

In conclusion, the component-based approach to UI creation, the virtual DOM for enhanced performance, and the sizable and welcoming developer community all contribute to ReactJS’ appeal among developers. ReactJS is an excellent option for creating sophisticated, high-performance online apps because of these capabilities, which also contribute to its continued popularity as a mainstay in many professional developers’ toolkits.

Components

What are components

Components are how ReactJS builds a user interface. In place of something like a button, a form, or a section of a website, they act as a user interface element. The creation of reusable, manageable programming using JavaScript components is possible.

Each component has its own state, or set of data that can be utilised to render the component. In reaction to particular events, such the user pressing a button, the component may update the state. After then, the component will render once more to reflect the altered state.

It is simpler to manage and maintain even the most complicated apps thanks to ReactJS’ component-based approach to UI development. Changes to one component have no impact on the rest of the application, and components are simple to combine to build a complete user interface.

In conclusion, ReactJS components are the building blocks of a user interface that enable reusable, manageable, and maintainable programming. They offer a technique to divide intricate user interfaces into more manageable chunks.

Creating components in ReactJS

Components in ReactJS can be created in a variety of ways, the most common among which is by using a JavaScript function or class.

Functional components are the most basic sort of component and are created using a JavaScript function. Here’s an example of a functional component in ReactJS:

function Greeting(props)
 {
return <h1>Hello, {props.name}</h1>;
}

Class components are much more complex and also include extra features such as the ability to handle state and lifecycle functions. Here’s an example of a ReactJS class component

class Greeting extends React.Component
 {
render() 
{
return <h1>Hello, {this.props.name}</h1>;
}
}

Once a component is created, it can be used in another component or in the main application by calling it like a regular HTML tag. For example:

<Greeting name="John Doe"/>

In this example, the Greeting component will be rendered with the name property set to “John Doe”.

To summarise, building components in ReactJS entails either using a JavaScript function or a class to specify the component and then invoking the component like a standard HTML element to render it in the application.

Virtual DOM

What is Virtual DOM

The Virtual DOM is a concept that was introduced in ReactJS and has since become a core part of its architecture. It is an abstract representation of the actual DOM (Document Object Model), and is used to update the UI more efficiently.

The Virtual DOM is a lightweight JavaScript object that acts as a replica of the actual DOM. When a component’s state changes, ReactJS updates the Virtual DOM instead of directly updating the actual DOM. It then performs a diffing algorithm to determine the most efficient way to update the actual DOM to reflect the changes made to the Virtual DOM.

The advantage of using a Virtual DOM is that it significantly improves the performance of updating the UI. When updating the actual DOM directly, the browser has to perform a large number of DOM operations, which can slow down the application. By using a Virtual DOM, ReactJS can minimize the number of DOM operations and only update the parts of the UI that have actually changed.

Benefits of Virtual DOM

• The Virtual DOM in ReactJS has various advantages, including:
• Improved performance: The Virtual DOM allows for faster UI modifications by lowering the amount of DOM operations. Even for complex programmes, this results in a better, more responsive user experience.
• Increased stability: The Virtual DOM contributes to the UI remaining stable and consistent even when the underlying data is changed. This decreases the possibility of unexpected UI actions and enhances the overall stability of the application.
• Ease of development: By abstracting away many of the DOM’s low-level features, the Virtual DOM makes it easier to design sophisticated applications. This allows developers to concentrate on developing the application’s functionality rather than worrying about the performance consequences of upgrading the UI.
• Improved debugging: Because the Virtual DOM separates the program’s state from the UI, it is easier to troubleshoot errors that develop in the application.

How  virtual DOM works in ReactJS

• • Components update their state: When a component’s state changes, ReactJS updates the Virtual DOM to reflect the new state.
  • ReactJS utilises a diffing algorithm: ReactJS then compares the prior version of the Virtual DOM to the modified version using a diffing technique. The diffing technique evaluates the most effective way to update the actual DOM based on whatever sections of the Virtual DOM have changed.
  • The actual DOM is updated: ReactJS then updates the actual DOM with the fewest operations required to bring it up to speed with the new Virtual DOM. This improves performance by reducing the amount of DOM operations.

• The browser re-renders the modified UI: Finally, the browser re-renders the updated UI, and the user sees the application’s new state.

JSX

What is JSX

JSX is a JavaScript syntactic extension that allows you to write HTML-like code within JavaScript. It first emerged in ReactJS and has since become an essential component of the framework’s design.

JSX allows you to design components in a more natural and straightforward manner since the structure of the component can be described using HTML-like syntax. This makes your code easier to comprehend, read, and write.

const element = <h1>Hello, world!</h1>;

A build tool, such as Babel, that is part of most of ReactJS applications, then converts JSX to JavaScript. The JavaScript code created is standard JavaScript that may be viewed in any modern browser.

Benefits of JSX

• Improved readability: Because the HTML-like syntax is more natural and intuitive than writing raw JavaScript, JSX makes components simpler to read and comprehend.
• Higher productivity: The ability to build components in a more natural and intuitive manner can lead to increased productivity since developers can focus on the component’s structure rather than the underlying JavaScript.
• Better tooling support: Because many development tools (such as code editors and linters) are geared for HTML-like syntax, using JSX can lead to better tooling support.
• Improved component reusability: Because components may be created using a basic, HTML-like syntax, JSX makes it easier to design reusable components.
• Improved type safety: Because type checking can be performed on the HTML-like syntax within the component rather than simply the final JavaScript code, JSX can aid enhance type safety.

How it works in ReactJS

• • Components are written using JSX: Components in ReactJS are defined using JSX, which is a syntax extension for JavaScript that allows you to write HTML-like code within your JavaScript code.
  • JSX is transpiled into JavaScript: The JSX code is then transpiled (converted) into JavaScript by a build tool like Babel, which is a standard part of most ReactJS projects. The resulting JavaScript code is plain JavaScript that can run in any modern browser.

• Components are rendered using ReactJS: ReactJS then uses the transpiled JavaScript code to render components on the page. When a component’s state changes, ReactJS updates the Virtual DOM to reflect the new state and then updates the actual DOM with the minimum number of operations necessary.

State and Props

What are State and Props

In ReactJS, state and props are two important concepts that you will use to build dynamic and interactive user interfaces.

State

The data or variables that control how a component operates and offers the user with information are referred to as its “state” in computing. In other terms, state refers to the data that a component manages and controls throughout time. A component that displays a list of items, for example, may have a state that comprises the items to be displayed, the selected item, and whether or not the list is currently being changed.

Props

Props are used to send data from a parent component to its child components. Props are used to move data down the component tree, in other words. For example, if a component shows a list of items, the parent component may provide list to the child component that displays the list as a prop.

Props are read-only, meaning that the child component cannot modify the props passed to it. Instead, if a child component needs to update the state, it can communicate this change to the parent component through a callback function. The parent component can then update the state and pass the updated state back down to the child component as props.

 Differences between State and Props

Ownership: The component that specifies the state owns it, whereas the parent component that sends it down owns the props. In other words, while a component has complete control over its own state, it cannot alter the props that are supplied to it.

Mutability: The state of the component can change over time, however the props are read-only and cannot be altered by the child component. If a child component needs to update the state, it must notify the parent component, which may then update the state and provide the new state as props.

Purpose: Purpose state is to manage and control the behaviour of a component and to present information to the user, whereas props are used to convey information down the component tree.

Initialization: State can be initialized in the constructor or using a state initializer, while props are passed down to a component as arguments when it is being instantiated.

Reusability: State is specific to a particular instance of a component and cannot be shared between components, while props can be shared between components and are used to make components reusable.

How to use them in ReactJS

Initializing State: You may initialise state in the function Object() { [native code] } of a component or with a state initializer. In the function Object() { [native code] }, you may set the initial state as a property of this, however in a state initializer, you can use the useState hook to establish the initial state.

class ExampleComponent extends React.Component {

 constructor(props) {

  super(props);

  this.state = {

    count: 0

   };

}

}

or

const ExampleFunctionComponent = () => {

  const [count, setCount] = useState(0);

  return (

   // ...

  );

}

Using State: This.state may be used to retrieve the state of a component. This.setState may be used to update the state as well. You might, for example, raise the state count by one as follows:

class ExampleComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0
    };
  }

  handleClick = () =>; {
    this.setState({
      count: this.state.count + 1
    });
  };
}

or

const ExampleFunctionComponent = () =>; {
  const [count, setCount] = useState(0);

  const handleClick = () =>; {
    setCount(count + 1);
  };

  return (
    // ...
  );
}

Passing Props: You can pass props down the component tree by including them as attributes in the JSX of the parent component. For example, you can pass a title prop to a child component as follows:

const ParentComponent = () => {

  return (

    <ChildComponent title="Hello World" />

  );

};

const ChildComponent = (props) => {

  return (

  <h1>{props.title}</h1>

 );

};

Using Props: You can access the props passed to a component using the props argument. For example, you can access the title prop in the child component as follows:

const ChildComponent = (props) => {

  return (

    <h1>{props.title}</h1>

  );

};

React Hooks

What are React Hooks

React Hooks are a feature in ReactJS that allow you to add state and other React features to functional components. Prior to React Hooks, state and other features were only available in class components.

React Hooks allow stateful code to be reused between components and are easier to comprehend and debug than class components. There are various built-in Hooks available, including useState, useEffect, and useContext, as well as the ability to construct your own custom Hooks.

import React, { useState } from 'react';

const ExampleFunctionComponent = () => {

 const [count, setCount] = useState(0);

  return (

    <div>
      <wp-p>You clicked {count} times</wp-p>

      <button onClick={() => setCount(count + 1)}>

        Click me

      </button>

   </div>

  );

};

The useState Hook is used in this example to add a count state to the component, which is set to 0. When the button is clicked, the setCount function is used to update the count state.

React Hooks enable you to write simpler, more legible, and reusable code, and they’re an excellent method to add state and other functionality to your functional components.

Types of React Hooks

React includes a number of Hooks that you can use in your components. Here are some of the most common Hooks:

• useState: Allows you to add state to your functional components.
• useEffect: Allows you to perform side effects in your components, such as fetching data or updating the DOM.
• useContext: Allows you to access data from the React context in your components, which can be useful for sharing data between components.
• useReducer: Provides an alternative to using useState for managing complex state.
• useMemo: Allows you to optimize the performance of your components by memoizing values.
• useCallback: Allows you to optimize the performance of your components by memoizing functions.
• useRef: Allows you to access the current value of a DOM element or a React component instance.

With React Hooks, you can add state and other features to your functional components while still writing reusable and efficient code.

How to use them in ReactJS

React Hooks can be used in functional components to add state and other features to your components. Here’s how you can use the useState Hook in a functional component:

import React, { useState } from 'react';

const ExampleFunctionComponent = () => {

 const [count, setCount] = useState(0);

  return (

  <div>

     <wp-p>You clicked {count} times</wp-p>

    <button onClick={() => setCount(count + 1)}>

      Click me

    </button>

  </div>

  );

};

In this example, the useState Hook is used to add a count state to the component, which is initialized to 0. The setCount function is used to update the count state when the button is clicked.

Here’s how you can use the useEffect Hook in a functional component:

import React, { useState, useEffect } from 'react';

const ExampleFunctionComponent = () => {

  const [count, setCount] = useState(0);
  useEffect(() => {

 document.title = `You clicked ${count} times`;

 }, [count]);

  return (

    <div>

    <wp-p>You clicked {count} times</wp-p>

    <button onClick={() => setCount(count + 1)}>

 Click me

     </button>

 </div>

  );

};

In this example, the useEffect Hook is used to update the document title whenever the count state changes.

Other Hooks, such as useContext, useReducer, or useMemo, must be imported from the react library and used in functional components. Each Hook’s precise usage will depend on your use case, but the core usage pattern is the same: you import the Hook, call it in your component, and utilise the returned data in your component’s render function.

 Conclusion

Summary of key points

ReactJS is a well-known JavaScript library for creating user interfaces. The following are some major points concerning ReactJS

ReactJS is based on the notion of components, which are reusable and composable user interface elements. Components might be class-based or functional in nature.

ReactJS makes use of a virtual DOM to swiftly and effectively refresh the UI. The virtual DOM decreases the amount of DOM modification necessary, which leads to better speed.

ReactJS defines components using JSX, a JavaScript grammar extension. JSX enables you to write HTML-like code within your JavaScript, making your code easier to comprehend and maintain.

Both state and props are used to control data and behaviour within ReactJS components. Props are handed down from the parent to the child, whereas state is maintained internally within the component.

Hooks are built-in to ReactJS and may be used to provide state, execute side effects, and more to your functional components.

Because ReactJS prioritises reusability and performance, it is a popular choice for creating sophisticated and large-scale user interfaces.

ReactJS has a big and active developer community, which contributes to its popularity and continuous development.

Future of ReactJS

ReactJS’s future looks bright, as it continues to increase popularity and utilization among developers. Here are a few of the reasons:

• Widespread adoption: ReactJS is used by many significant firms, like Facebook, Airbnb, and Netflix, and it has a huge and active developer community.
• Growing demand for React Native: React Native, a framework for building native mobile apps using ReactJS, has grown in popularity and demand, and is expected to continue to grow in the future.
• Constant evolution and development: ReactJS is constantly evolving and being developed, with new features, updates, and improvements being added regularly.
• Integration with other technologies: ReactJS can be easily integrated with other technologies, such as GraphQL and TypeScript, making it a versatile and flexible choice for building a wide variety of applications.
• Focus on performance and developer experience: ReactJS has a strong focus on performance and developer experience, and this is expected to continue to be a priority in the future.

This brings us to the end of this blog on what is React. Hope I was able to clearly explain what is React and why you should use it. You can refer to this ReactJS tutorial, in case you want to learn more about ReactJS. 

Got a question for us? Please mention it in the comments section and we will get back to you.