A Complete Guide on Reactjs for Developers

React, the most exciting topic in the modern developer’s world. With the arrival of the react technology, it has vanished numerous problems of the developers. Let’s begin with the topic of the day – Reactjs.

What is React?

React is an open-source JavaScript library that makes it painless to create beautiful user interfaces. Reactjs is

• a javascript library
• not a framework
• Facebook’s open-source project
• Used to create front end UIs
  As we all aware of the fact that in the past times, in web application programming, even for small changes, you need to reload the whole webpage. But Reactjs has solved the problem as it updates only what’s necessary.

History of Reactjs

Reactjs was introduced by Facebook’s software engineer in 2013. Reactjs is extensively used by reputed companies and brands like Facebook, Instagram, etc.

Market Research

According to the Google Trends report, Reactjs’s popularity is almost the same as the last 12 months.

In addition to this, as per the statistics of the SimilarTech Website, in the United States, the highest number of websites are developed with the React (2 Million); however, China(111,577) and Indonesia(40,578) got second and third places, respectively.

Read More: How to do React Migration? React Migration Best Practices

React used by the companies

The top brands and companies that use React in their websites are Facebook, Instagram, Uber, Udemy, Twitter, Netflix, etc.

Why is React so popular?

React has pushed the frontend development to the next level. One of the primary features of React is that it allows the developers to create the large/complex UIs with the help of the small and isolated pieces of code-named “Components” that can be changed without reloading the whole page. React is much easier to use than the other frontend frameworks or libraries.

Features of Reactjs

JSX(JavaScript + XML)

JSX is XML syntax extension to Javascript. React allows you to develop with or without JSX, but JSX makes it more elegant. JSX works on the syntax of XML like it has the tag name, attributes, and children.

React is unidirectional

React allows the single-way data flow. It is based on the process of “properties flow down, actions flow up” You can not modify the properties directly; a callback function will be passed to do modifications in the properties.

Virtual DOM(Data-Object-Model)

Virtual DOM. React creates the in-memory and virtual data structure, which computes the changes made and displays on the browser. The unique feature of React allows the developers to make changes, and when there is a need to render the whole page, then the React library reloads only the essential one.

“If you make the same thing twice, then ReactDOM.render will do nothing.”

Learn React Development: A Detailed Guide

Let’s first understand the primary concepts of React.

• Components
• Component State
• Component Props
• JSX
• Event Handlers
• Rendering Elements

Components

Components are the separate pieces of the React applications. React is the combination of several parts(components). To illustrate, on Facebook, you can like, comment, and share the status post; all these widgets are known as the Components to React. All of the reusable parts of the web pages are combined in the components to use repeatedly.

Within every component, there is a subcomponent that can be reused again. In this case, the LinkStatus and PhotoStatus are the components, and action buttons are the child(subcomponents).

How to define the component in React?

Here is an example of how to use the function components

Component Props

“COMPONENT-PROPS USED FOR PROPERTIES TO PASSED IN THE COMPONENTS.”

React re-renders whenever a component changes its State. So, here props are the object given to a component by its parent component. Props are essential to pass when a parent component changes its State.

As you can see, a function is a React component, as it accepts the arguments like props and returns a React element.

Read More: How to Create Product Tours in React Apps?

Component State

“COMPONENT-STATE USED TO DEFINE THE BEHAVIOR OF A COMPONENT AT THE MOMENT.”

In simple words, the State is a JS object that records user events. The State is one of the most confusing concepts in React, but it is an essential React feature. As it monitors the user’s actions, whenever a class-based component changed its states, it re-renders the components with all of its subcomponents.

Use this.state.characters – to retrieve the state
Use this.setState() – to update the state

JSX (Javascript + XML)

JSX is an extension of Javascript that illustrates how UI will look like. You can use the React with or without JSX. But, in some of the cases, without JSX, React is horrible. One of the primary benefits of using the React with JSX that it allows you to interact with only the Javascript objects, not with the template strings. Here is the example of how to define the h1 tag containing string:

It looks like a combination of HTML and Javascript, but in reality, it’s all Javascript. JSX, when introduced, is no longer a React-only technology.

Event Handlers

Event Handling in React is slightly different from JavaScript and HTML. In fact, Handling events in React is quite similar to event handling in DOM elements. For instance:

In HTML

In React

Moreover, React’s events written in camelCase, rather than in lowercase.

Rendering Elements

Do you know? Elements are the smallest pieces of the React apps. Means smaller than the components also. How do elements look like?

Element Rendering in DOM, using ReactDOM.render()

Wrapping it up

The secret behind the popularity of React is the use of components. React has made frontend development much easier as compared to other frontend technologies. React is the perfect choice for web app development, single app development, etc. For the best Reactjs development services, you can hire Reactjs developer of the company Tekki Web Solutions Pvt.Ltd.