##What problem faced by fb that they created ReactJS?

• Updating the UI with rapidly changing data .

The key features of React are:

• Component-based: Components are the smallest unit in a React application. Anything that we want to render is rendered through components. Components help in maintainability and
• Virtual DOM: React uses virtual DOM concept for DOM manipulation which improves the performance of the application
• Unidirectional data flow: React’s one-way data flow (also called one-way binding) keeps everything modular and fast and easy for debugging.
• JSX syntax: React used JSX syntax which is similar to XML and HTML syntax which makes it easy for writing markup and binding events in components
• SEO performance: The SEO performance can be improved using the server-side rendering concept. We can develop isomorphic applications using React which increases the SEO performance.