React is a Javascript library for frontend development that allows for greater flexibility and fluidity when developing widgets and web apps. React uses a virtual DOM (document object model) to update its UI elements, then compares the virtual DOM with its current DOM, then renders the changes. Furthermore, React can keep track of UI elements' states and renders the UI elements based off of the states. React's goal is to be fast, simple, and scalable and create web apps that use data that changes over time without having to reload the page.

The use of the virtual DOM is one of the most important features of React. For large websites whenever a change is made, the DOM has to be manipulated. Most javascript frameworks update the entire DOM with every change, regardless of how small. This is a very slow process. React makes a copy of the DOM, the virtual DOM, which updates much faster. When a change is made to the website the entire virtual DOM updates, the changes are compared to the real DOM, then only the changed aspects of the real DOM are updated.

• Official React page
• Official React tutorial
• LearnCode.academy video series
• Wes Bos Reduxstagram tutorial
• Codecademy React tutorial 1
• Codecademy React tutorial 2

Presentation Slides on Google Drive, and in PDF: reactpresentation.pdf