Complete React Introduction

Let’s have a React introduction, ReactJS is an efficient, declarative, and adaptable JavaScript library for building reused UI components. It is an open-source component-based front-end library responsible only for handling the view component of an application. It was designed by Jordan Walke, an engineer working at Facebook. The library was created as a maintenance project by Facebook and later was used in the products of Facebook, such as WhatsApp & Instagram. Facebook developed ReactJS in 2011 within its newsfeed section. However, it was made available to the public in April 2013.

Nowadays, most websites are built with MVC (model view controller) architecture. React is the ‘V’ that stands for view in the MVC design. Redux and Flux offer the architecture.

A ReactJS application is composed of several components, each responsible for generating tiny, reusable pieces made of HTML code. Components form the basis of the entire React applications. They can be nestled together with other components to permit complicated applications to be made of basic components. ReactJS uses a virtual DOM as a mechanism to fill information in HTML DOM.

The virtual DOM is fast because it only alters the individual DOM elements, instead of loading all the DOM each time.

To develop a React application, We create React components that correspond to different elements. They are organized in higher-level components, which define the app’s structure. For example, let’s consider an application form with numerous elements such as labels, input fields, or buttons.

The form components can be written for each form in React components. Then we integrate them to form a higher-level component, i.e. the component used to create the form. Form components will define the layout of the form and the components within it.

React Introduction

Nowadays, various JavaScript frameworks are on the market(like Node and angular); however, React came into the market and became popular among the other frameworks. The older frameworks use the conventional data flow model, which relies on an object model called DOM (Document Object Model). DOM is an object created by the browser every time a page on the internet is loaded. It adds or deletes the information at the back end, and after any changes are made the next time the page loads, a new DOM is made for the same page. The repeated creation of DOM results in unnecessary memory consumption and slows down the application’s performance.

A brand-new technology, ReactJS, has been developed to eliminate this limitation. ReactJS allows you to divide your entire application into various components. ReactJS is still using the traditional data flow; however, it does not operate in conjunction with the web browser’s Document Object Model (DOM) instantly; rather, it is operating through the virtual DOM.

Instead of manipulating the document within the browser following changes made to the data, it can resolve the changes to the basis of a DOM constructed and running in memory. Once the virtual DOM has been modified, React determines what changes have been made to the browser’s DOM.

The React Virtual DOM is completely in memory and serves as an image of the DOM displayed by the browser. Because of this, when we create React components, we are not writing directly to the DOM. React component is because we do not write directly to DOM, but instead write virtual components that react and transform into DOM.