ReactJS Tutorial

React is a JavaScript library for building user interfaces. It was developed by Facebook, and is often used for building single-page applications and mobile applications.

React works by creating a virtual DOM (Document Object Model) in memory, which is a lightweight representation of the actual DOM. When a React component is rendered, it creates a new virtual DOM element, which is then compared to the previous virtual DOM element. If there are any differences between the two, React will update the actual DOM to reflect the changes. This process is called "reconciliation."

One of the main benefits of using React is that it can improve the performance of an application by limiting the amount of DOM manipulation that needs to be done. Because React only updates the parts of the DOM that have changed, rather than re-rendering the entire page, it can significantly reduce the number of DOM operations that need to be performed.

In addition to its performance benefits, React also makes it easier to build reusable UI components. Components are the building blocks of a React application, and they can be reused throughout the app. This makes it easier to build and maintain complex applications, as you can reuse existing components rather than having to build everything from scratch.

React uses a declarative programming style, which means that you describe what you want the UI to look like, and React will handle the details of how to change the UI to match your description. This can make it easier to understand and debug an application, as you can see what the UI should look like based on the code that you've written.

ReactJS History

React was developed by Facebook in 2011 as a way to build efficient, reusable UI components for the company's internal web applications. The first version of React, known as "React 0.3," was released in May 2011.

In 2013, Facebook released React as an open-source project, making it available for anyone to use. Since then, React has become one of the most popular JavaScript libraries for building user interfaces, and is used by many companies and organizations around the world.

One of the key features of React is its virtual DOM (Document Object Model), which allows it to efficiently update the actual DOM when a component's state changes. This makes React particularly well-suited for building large and complex applications, as it can significantly reduce the amount of DOM manipulation that needs to be done.

In 2015, Facebook released React Native, a framework for building native mobile applications using React. This made it possible to use the same concepts and principles of React to build iOS and Android apps, making it easier to share code between different platforms.

React has continued to evolve and improve over the years, with new features and capabilities being added in each release. The current version of React, as of September 2021, is 17.0.

ReactJS Key Features

Here are some key features of React:

  1. Declarative: React uses a declarative programming style, which means that you describe what you want the UI to look like, and React will handle the details of how to change the UI to match your description. This can make it easier to understand and debug an application, as you can see what the UI should look like based on the code that you've written.

  2. Reusable components: React makes it easy to build reusable UI components. Components are the building blocks of a React application, and they can be reused throughout the app. This makes it easier to build and maintain complex applications, as you can reuse existing components rather than having to build everything from scratch.

  3. Virtual DOM: React uses a virtual DOM (Document Object Model) in memory, which is a lightweight representation of the actual DOM. When a React component is rendered, it creates a new virtual DOM element, which is then compared to the previous virtual DOM element. If there are any differences between the two, React will update the actual DOM to reflect the changes. This process is called "reconciliation."

  4. Performance: One of the main benefits of using React is that it can improve the performance of an application by limiting the amount of DOM manipulation that needs to be done. Because React only updates the parts of the DOM that have changed, rather than re-rendering the entire page, it can significantly reduce the number of DOM operations that need to be performed.

  5. JSX: React components are written using JSX, a syntax extension for JavaScript that allows you to write HTML-like code within JavaScript. This can make it easier to read and write React components, as the JSX syntax closely resembles HTML.

  6. State: React components can have state, which is data that is specific to a component and can change over time. State allows you to build dynamic and interactive applications by storing data within a component and using it to update the component's UI.

  7. Hooks: React has a feature called "hooks" that allows you to use state and other React features without writing a class. Hooks are functions that let you "hook into" React state and lifecycle features from function components. They make it easier to reuse stateful logic and can help make your code more concise.

  8. Server-side rendering: React can be used to render applications on the server, allowing you to build isomorphic or universal applications that can run on both the client and the server. This can improve the performance of your application, as the initial render can be done on the server, reducing the amount of work that needs to be done on the client.

  9. Testing: React has a strong ecosystem of tools and libraries for testing components and applications. These tools can help you catch bugs and ensure that your application is working as expected.

  10. Community: React has a large and active community of developers, with many helpful resources and libraries available. This makes it easier to get help and support when working with React, and also allows you to benefit from the work of other developers.