react-is provides utilities for testing React elements against their type. Crucially, it helps determine the type of a React element created by a function like React.createElement. This is useful for libraries that need to introspect React components to apply specific logic. Determine if something is a React.Fragment, a React.Memo, a React.Context, or other React types without relying on internal properties, ensuring compatibility across React versions. Essential for building higher-order components or analyzing React component trees.