React.js is a JavaScript library for building user interfaces that allows developers to build complex UIs without pain by only re-rendering components when data changes rather than entire pages. It uses a virtual DOM for diffing and applying only necessary changes to the real DOM. React allows developers to write code in JSX, uses propTypes for type checking, mixins for code reuse, and can be used for server-side rendering to improve performance on initial page loads and pre-rendering for mobile devices. React Native also allows building native mobile apps using React by compiling JSX to native platform elements.

1. React.js
For Back-End developers
Artyom Trityak

2. • Building complex UI without pain
• Simple Flow - whole page / widget re-render on
each change
• React.js will do Diff and apply only needed
changes to DOM
React? What is React?

3. JSX, Virtual DOM

4. PropTypes

5. Mixins

6. Result

7. JSX -> JS compiler
React Rails
PyReact, Django React
Grunt.js React, Gulp.js React

8. • SEO - no need PhantomJS-renderer
• First page loading speedup
• Pre-render for mobile devices
Server Side Rendering

9. Server Side Rendering: Node.js

10. Server Side Rendering: Ruby on Rails

11. Server Side Rendering: Django

13. +Bonus
React Native

14. • No WebView
• No browser
• JavaScript logic in separate thread does not block
Native UI
• JSX HTML -> Native platform elements
• Learn once, write everywhere
• Example: http://www.facebookgroups.com/
React Native