React
There are many frameworks and libraries that facilitate development of Web application, in particular its front-end component, the user interface, or UI.
Among these, React is perhaps the most popular. It was developed by a group of Facebook engineers, initially at Facebook.
In this module we learn to work with React. As a first step, we will rebuild our good old SleepTime App in React!
React has a great documentation and set of tutorials on its Website. The best place to learn React is there! I also found this article to have a good overview: The Missing Introduction to React.
Here are some other reads you may be interest in: