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.
One of the key features of React is its ability to update the user interface efficiently. When data changes in a React application, the React framework only updates the parts of the user interface that are affected by the change, rather than updating the entire interface. This makes it faster and more efficient than other JavaScript libraries or frameworks that update the entire user interface whenever there is a change in the data.
React uses a virtual DOM (a lightweight in-memory representation of the actual DOM) to optimize updates to the user interface. When the data changes, React creates a new virtual DOM representation of the user interface, and then determines the minimal number of changes that need to be made to the actual DOM in order to reflect the new virtual DOM. This process is called “reconciliation”.
React is also known for its use of JSX, a syntax extension that allows developers to write HTML-like code in their JavaScript files. JSX makes it easier to write and maintain code that generates the user interface, and it also makes the code more readable. However, JSX is not required to use React, and you can also use React without JSX if you prefer.
How does React Work?
React works by building a virtual representation of the user interface using a virtual DOM (a lightweight in-memory tree-like structure). When the data that is displayed in the user interface changes, React creates a new virtual DOM representation of the updated user interface. It then compares the new virtual DOM to the previous virtual DOM, and determines the minimal number of changes that need to be made to the actual DOM in order to reflect the new virtual DOM. This process is called “reconciliation”.
The virtual DOM is a fast and efficient way to update the user interface, because it avoids the need to update the entire DOM tree whenever the data changes. Instead, it only updates the parts of the DOM that have actually changed, which makes the updates faster and more efficient.
In addition to the virtual DOM, React also provides a declarative API for building user interfaces. This means that you can specify what you want the user interface to look like, and React will take care of rendering the interface and updating it whenever the data changes. This makes it easier to build and maintain complex user interfaces, because you don’t have to worry about how to update the interface when the data changes.
React also provides a component-based architecture for building user interfaces. Components are reusable pieces of code that represent a part of the user interface. They can be combined to build more complex user interfaces, and they make it easier to reason about and maintain the code.
Overall, React is a powerful and efficient tool for building user interfaces, and it is widely used by developers around the world.
React.JS History
React was developed by Facebook in 2011 as a way to build more efficient and maintainable user interfaces. The first version of React was released in 2013, and it quickly gained popularity among developers due to its simplicity and efficiency.
In 2015, Facebook released React Native, which allows developers to use React to build native mobile applications for iOS and Android. This made it possible to build high-quality native mobile apps using the same declarative approach and reusable components that React provided for the web.
Since its release, React has become one of the most popular JavaScript libraries for building user interfaces, and it is widely used by companies and developers around the world. In 2019, React was the most popular project on GitHub in the “JavaScript” category, with over 100,000 stars and more than 40,000 forks.
In recent years, React has also spawned a number of related projects, including React Router (for building single-page applications with multiple routes), Redux (for managing application state), and Gatsby (a static site generator for building fast and performant websites). These tools and libraries have made it even easier for developers to build complex and powerful web and mobile applications using React.