What is useDeferredValue in React?

useDeferredValue is a React Hook introduced in React 18, used to defer a piece of state to make rendering less urgent. It allows React to render an updated value at a lower priority, improving responsiveness for high-priority interactions.

function ExpensiveComponent({ value }) {
  console.log("Rendering ExpensiveComponent");
  // Simulate expensive computation
  const items = Array.from({ length: 10000 }, (_, i) => i + value);
  return <div>{items.slice(0, 5).join(", ")}</div>;
}

function App() {
  const [input, setInput] = useState("");
  const deferredInput = useDeferredValue(input);

  return (
    <div>
      <input value={input} onChange={(e) => setInput(e.target.value)} />
      <ExpensiveComponent value={deferredInput} />
    </div>
  );
}

In this example, deferredInput updates at a lower priority, ensuring that typing in the input remains responsive even if rendering deferredInput is expensive.