ReactJS Introduction - rimander123/react-js-training-course GitHub Wiki
ReactJS is a ES6 JavaScript library that combines the speed of JavaScript and uses a new way of rendering webpages, making them highly dynamic and responsive to user input.
Unlike other frameworks that work with the Real DOM, ReactJS uses its abstract copy – the Virtual DOM. It updates even minimalistic changes applied by the user, but doesn’t affect other parts of interface. That is also possible thanks to React components isolation, and a special data structure in the library.
This approach enabled to work with UI-objects faster and use hot reloading (applying changes in a real-time mode). Not only did it increase performance, it also made programming faster.
React Components are independent and reusable bits of code. They serve the same purpose as JavaScript functions, but work in isolation and returns HTML via a render function using JSX which allows mixing HTML with JavaScript.