What approach does React use — imperative or declarative? What is the difference?

React uses a declarative approach.

Declarative approach means that you describe what the result (UI) should be, not how to achieve it. You specify what should be displayed given a certain state, and React takes care of updating the DOM accordingly.

Imperative approach is when you explicitly control the steps to change the interface, for example, by directly manipulating the DOM through methods like document.createElement, appendChild, etc.

In React, you describe components as functions from state to UI, rather than writing instructions for changing the interface. This simplifies understanding and maintaining the code.

Example of declarative code in React:

function Greeting({ isLoggedIn }) {
  return (
    <div>
      {isLoggedIn ? <p>Hello, user!</p> : <p>Please log in.</p>}
    </div>
  );
}