What is Reactjs? React JS Tutorial Guide for Beginners

ReactJS is a popular framework that brought a revolution in the world of web development. A few years ago, the user needs to refresh the web page to check any new message or updated information, but now web pages are refreshed automatically after a certain period of time.

Even through pop-up notifications, you may know about any recent changes or updates on the web page. Do you know how is it happening, well this all magic is just due to ReactJS? In this blog, we are going to introduce ReactJS and its various functionalities and why you should use React?

What is ReactJS and Why to Use this framework?

JavaScript programming is widely used to develop web applications as it is a lightweight language that is supported by all browsers. It supports the procedural and object-oriented languages, so it is used to create client-side scripts to make dynamic web-pages.

Many frameworks can be used with JavaScript depending on the project requirements and React framework is one of them. JavaScript is one of the most preferred scripting languages used by the web designers and it offers the following features to web projects:

• Security
• Efficiency
• Cost Reduction

React is giving a neck to neck competition to Angular that is a quite older framework for JavaScript due to its array of features. The main reason behind the popularity of ReactJS is the way in which data flow takes place. Earlier the frameworks were using the traditional approach in which the web pages need to be refreshed to check any update.

Web pages can receive data from any source like real-time data, user input data, or initial data that can be dispatched by any dispatcher. After fetching data, it is usually forwarded to the store that transfers it to view. Through view, you or any other user can interact with the web application, so web pages come in view category of MVC architecture.

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Do you know that in this traditional approach every time new data is added at the back end? At the time when the browser gets updates only then the user can see the new data on the view. This complete update cycle is handled by DOM or Document Object Model that is created by the browser when the web page is loaded or refreshed and it can dynamically add or remove data to and from the web page. Though Dom creation is done dynamically, this is memory wastage and degrades the overall application performance too.

As the Dom creation process was costly and inefficient, so a new technology was needed to save time and resources. ReactJS is proved such an efficient technology, that provides a new way to perform this task of handling views at the client side. Through ReactJS, a single application can be divided into many components, same traditional data flow technique is used in ReactJS, but at the back end, the way to handle data has been changed.

In ReactJS, when data gets the update it does not reload the full web page, instead, it reloads a portion of the web page and updates only selected component that was changed. Moreover, ReactJS uses virtual DOM instead of DOM to save the memory space.

Learn ReactJS – A quick Introduction guide to Beginners

ReactJS is not a framework instead is a component-based library that was introduced by the Facebook. Now it is one of the most popular JavaScript libraries with a strong foundation and large supportive community. In ReactJS, everything is just like a component that is taken as the basic building blocks of the application.

Here, the use of component makes ReactJS an efficient library collection as they are easy to handle, one can change just a single component when it is required rather than changing the complete page layout. For real-time or large sized applications, this feature is quite important. In ReactJS, component states get changed when they are updated. As a result, the whole page need not be reloaded when the application gets changed.

This library was developed by Facebook’s software engineer Jordan Walke and initially, Facebook implemented ReactJS in its news feed in 2011, while by 2013 it was made available for every user. Use of ReactJS made Facebook more popular and many users get satisfied by this. Now any of the JavaScript users can use this set of the library that was initially used only by the Facebook.

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ReactJS Tutorial Guide – What are the Features?

Now it may become clear to you that what is ReactJS and why is it used. So, now let's look at its features, what are the intriguing features of ReactJS:

1). Virtual DOM

Just like real DOM, virtual DOM is also a node tree in which elements, their attributes, and content work as objects and properties. In React, a node tree is created by the render function in which all components of React are used. This tree gets updated as per the changes of components either by the user or system, this rotation is called mutation. Tree mutation is performed in these three simple steps:

1. On changing of any underlying data complete UI is re-rendered virtually.
2. Difference between current and previous DOM is calculated
3. As per result of the calculation, DOM gets changed

These changes are applied to a certain part of the application, rather than complete application and so application becomes faster and less memory gets wasted.

2). Use of JSX

JSX stands for JavaScript XML. For JSX files, ‘react’ uses HTML/XML like syntaxes, that can be used by Babel-like pre-processors and through that HTML like syntaxes can be transformed easily to Java objects. Through JSX after CONVERSION TO JavaScript objects, again the code can be embedded inside JavaScript. These JSX files make the HTML code easy to understand and helps in boosting the overall application performance too. Applications become robust due to these files.

3). Testability

ReactJS makes an application testable and it is easy to debug and test. It uses views that can be used as the states of the functions. Component states can be easily manipulated and passed to the ReactJS view, where the action, function, and event can be easily checked and tested. ReactJS has improved application quality by providing feature rich libraries.

4). Simplicity

ReactJS JSX files are really easy and simple to understand. The user can quickly code and understand JSX files. Though plain JavaScript can also be used here, it is quite easier to use JSX files. As it is a component-based library, in which each component has a separate life cycle, so it is easier to use ReactJS.

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5). Low Learning Curve

ReactJS learning curve is low and easier. Anyone who has even basic programming knowledge can learn and use ReactJS. So, even if you have basic programming skills and know how to code in HTML and JavaScript, then you can learn ReactJS quickly.

6). One-way Data Binding

In ReactJS, uni-directional data flow is used that is also called data binding. Here, application states are kept in specific stores and therefore rest of the components remain loosely coupled and as a result application becomes more flexible and efficient.

Learn Basic Building Blocks of ReactJS

However, anyone who has a little bit knowledge of HTML, but still it is good to know the basic building blocks of ReactJS so that you can design and use the application as per your requirements. ReactJS treats everything as a component that may have certain specific props, state, and lifecycle and so on. So, in short, we can say that ReactJS has following building blocks:

• Components: An application consists of many components that are used to serve different purposes. This way we can keep the view and logic separate. These ReactJS components can either be stateful or stateless. While defining components, we firstly import react-dom libraries and then we can code for the component.
• Properties or Props: Props is used by React components to pass parent properties to child components. These are like arguments that are passed to the ReactJS functions or components that are then processed by the React.
• State: States helps to create interactive and dynamic components. Generally, it is used with data that changes frequently. Like a button or property can be in the active or inactive state, we can use it through render function and can be set inside constructors.
• Event Handling or State Manipulation: Events like the click of button or mouse hovering may require some action. Event handlers are used to handle such events. Initially, the component state can be set in constructors, but if required, these states can be manipulated by using the setState command. Moreover, the IsToggleOn function can switch the state from active to inactive or vice versa.
• State Lifecycle: As component requirements, resources need to be initialized. This initialization of resources is called “mounting”. Mounting and un-mounting of resources can be done by the ReactJS easily and for this, there are ready to use functions available in the React framework.

Final Words With this blog, we know what is ReactJS and a complete comprehensive tutorial guide for beginners. Hence, we can say that ReactJS is a library that has many features. These libraries can be used to define the application in a simpler way. ReactJS has many features and one of the most used and compelling ones is its component-based architecture. It makes application easy to debug and test as well.

Read More: Reactjs Interview Questions

With this ReactJS Tutorial guide for beginners, you will not only have a basic idea of the framework but you can implement the same in real-life projects too. For a detailed guide, you should join JanBask Training certification programs now and start excelling in your career right away.

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