# React

Conceptually, components are like JavaScript functions. They accept arbitrary inputs and return React elements describing what should appear on the screen.

Material UI uses Emotion as its default styling engine. Emotion is a library designed for writing css styles with JavaScript.

When a component's props or state change, React decides whether an actual DOM update is necessary by comparing the same with Virtual DOM...

A common pattern is for a component to return a list of children...

Fragments declared with the explicit <React.Fragment> syntax may have keys.

A common pattern in React is for a component to return multiple elements. Fragments let you group a list of children without adding extra nodes to the DOM.