One of the most well-known JavaScript frameworks, developed by Facebook, transformed the way we think while developing. It introduced the concept of components, so you no longer write the HTML layer of the whole page, then style with the CSS layer, and finally add functionality with JS. Development is now modular, so you write all three for one component at a time (for example a button), and plug it in in as many places it is needed. This speeds up development greatly, especially in AJAX-enabled pages. Our developers use React patterns like Higher Order Components, Layout Components, or State Hoisting. Of course, bigger applications must use patterns as Flux or Redux helped by the power of Sagas. We try to leverage Functional programming and use Pure functions whenever possible.