Why is React needed? What problems does it solve? When is it excessive?

React is a library for building user interfaces that addresses the problem of efficiently updating the UI when data changes.

Problems that React solves:

• Allows describing the interface declaratively using components.
• Uses a virtual DOM to minimize actual changes to the DOM, which improves performance.
• Provides convenient management of component state and lifecycle.
• Simplifies creating complex interfaces through component composition.

When React is excessive:

• For very simple static pages where there is no interactivity.
• If the project is small and does not require dynamic UI updates.
• In cases where adding React increases the complexity and size of the application without clear benefits.

Thus, React is useful for dynamic, interactive applications with frequent UI changes, but can be excessive for simple websites or pages.