Lesson 1 of 6By Taha Sufiyan
Last updated on Apr 9, 202187962React is the most popular front-end JavaScript library in the field of web development. It is used by large, established companies and newly-minted startups alike (Netflix, Airbnb, Instagram, and the New York Times, to name a few). React brings many advantages to the table, making it a better choice than other frameworks like Angular.js.
If you’re new to ReactJS or just refreshing yourself on the core concepts, this article will give you an introduction to all of React’s fundamentals. We’ll be covering the following topics in this article:
React is a JavaScript library created for building fast and interactive user interfaces for web and mobile applications. It is an open-source, component-based, front-end library responsible only for the application’s view layer. In Model View Controller (MVC) architecture, the view layer is responsible for how the app looks and feels. React was created by Jordan Walke, a software engineer at Facebook.
Fig: MVC architecture
Let’s take a look at an Instagram webpage example, entirely built using React, to get a better understanding of how React works. As the illustration shows, React divides the UI into multiple components, which makes the code easier to debug. This way, each component has its property and function.
Fig: Instagram Components
Now that we know what React is let’s move on and see why React is the most popular front-end library for web application development.
React’s popularity today has eclipsed that of all other front-end development frameworks. Here is why:
The above reasons more than justify the popularity of the React library and why it is being adopted by a large number of organizations and businesses. Now let’s familiarize ourselves with React’s features.
Fig: React Features
JSX is a syntax extension to JavaScript. It is used with React to describe what the user interface should look like. By using JSX, we can write HTML structures in the same file that contains JavaScript code. This makes the code easier to understand and debug, as it avoids the usage of complex JavaScript DOM structures.
const name = 'Simplilearn';
const greet = <h1>Hello, {name}</h1>;
The above code shows how JSX is implemented in React. It is neither a string nor HTML. Instead, it embeds HTML into JavaScript code.
React keeps a lightweight representation of the “real” DOM in the memory, and that is known as the “virtual” DOM (VDOM). Manipulating real DOM is much slower than manipulating VDOM because nothing gets drawn on the screen. When the state of an object changes, VDOM changes only that object in the real DOM instead of updating all of the objects.
It may all seem a bit overwhelming for now, so let’s first understand what DOM is, and then we’ll go through how VDOM and real DOM interact with each other.
Fig: DOM of a Webpage
DOM (Document Object Model) treats an XML or HTML document as a tree structure in which each node is an object representing a part of the document.
Fig: Virtual DOM
When the state of an object changes in a React application, VDOM gets updated. It then compares its previous state and then updates only those objects in the real DOM instead of updating all of the objects. This makes things move fast, especially when compared to other front-end technologies that have to update each object even if only a single object changes in the web application.
React uses VDOM, which makes the web applications run much faster than those developed with alternate front-end frameworks. React breaks a complex user interface into individual components, allowing multiple users to work on each component simultaneously, thereby speeding up the development time.
React goes beyond simple UI design and has many extensions that offer complete application architecture support. It provides server-side rendering, which entails rendering a normally client-side only web application on the server, and then sends a fully rendered page to the client. It also employs Flux and Redux extensively in web application development. Finally, there is React Native, a popular framework derived from React, used to create cross-compatible mobile applications.
React’s one-way data binding keeps everything modular and fast. A unidirectional data flow means that when a developer designs a React app, they often nest child components within parent components. This way, a developer knows where and when an error occurs, giving them better control of the whole web application.
Fig: One-way data binding
React applications are easy to test due to a large developer community. Facebook even provides a small browser extension that makes React debugging faster and easier.
Fig: React Extension
This extension, for example, adds a React tab in the developer tools option within the Chrome web browser. The tab makes it easy to inspect React components directly.
Now, let’s take a look at React’s important concepts.
Components are the building blocks of any React application, and a single app usually consists of multiple components. A component is essentially a piece of the user interface. React splits the UI into independent, reusable parts that can be processed separately.
There are two types of components in React:
Fig: React Components
function Greeting(props) {
return <h1>Welcome to {props.name}</h1>;
}
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class Greeting extends React.Component {
render() {
return <h1>Welcome to {this.props.name}</h1>;
}
}
The state is a built-in React object that is used to contain data or information about the component. A component’s state can change over time; whenever it changes, the component re-renders. The change in state can happen as a response to user action or system-generated events, and these changes determine the behavior of the component and how it will render.
class Greetings extends React.Component {
state = {
name: "World"
};
updateName() {
this.setState({ name: "Simplilearn" });
}
render() {
return(
<div>
{this.state.name}
</div>
)
}
}
Props are short for properties. It is a React built-in object which stores the value of a tag’s attributes and works similar to the HTML attributes. It provides a way to pass data from one component to other components in the same way as arguments are passed in a function.
In summary, components, state, and props are React’s fundamental concepts. Before you start working on React, there are a few concepts that which you should already be familiar with. We discuss the prerequisites below.
Master the fundamentals of React—an important web framework for developing user interfaces—including JSX, props, state, and events with the React.js Training Course.
Here are some of the concepts that you should be familiar with, to one degree or another:
Now that you know what concepts you should already be familiar with before working on React, let’s take a look at the industry trends.
“React” has become the latest buzzword in the front-end development community, reflecting its steadily increasing use among developers.
The average salary for a React developer across the United States is a whopping USD 91,000 per year!
The average salary for a React developer in India is ₹7,25,000 per year!
Now that you have React’s basics down, you may be wondering how you can obtain the skills necessary to take advantage of its rising popularity. Simplilearn offers a comprehensive React.js Training Course, which will help you become career-ready upon completion. To learn more, check out our YouTube playlist covering the fundamental concepts of React in greater depth. If you’re a web and mobile developer, React training will help you broaden your skills and your career horizons.
Name | Date | Place | |
---|---|---|---|
React.js | 14 May -4 Jun 2021, Weekdays batch | Your City | View Details |
Taha is a Research Analyst at Simplilearn. He is passionate about building great user interfaces and keeps himself updated on the world of Artificial Intelligence. Taha is also interested in gaming and photography.
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