Q331. What is the useOptimistic hook?
`useOptimistic` enables optimistic UI updates - showing changes immediately before server confirmation. #### Basic Usage ```jsx import { useOptimistic } from 'react'; fun...
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Q332. What is the React Compiler (React Forget)?
The **React Compiler** (formerly known as React Forget) automatically optimizes your components by adding memoization where needed - eliminating the need for manual `useM...
Q333. What is Streaming SSR and how does React 18+ improve it?
**Streaming SSR** sends HTML to the browser in chunks as it's generated, rather than waiting for the entire page. React 18+ dramatically improves this with Suspense integ...
Q334. What is `renderToPipeableStream` and how is it different from `renderToString`?
`renderToPipeableStream` is the React 18+ Node.js streaming SSR API from `react-dom/server`. It streams HTML in chunks, so users can see content earlier and React can coo...
Q335. What is the difference between HOCs and Hooks?
Both **Higher-Order Components (HOCs)** and **Hooks** let you reuse logic across components, but they solve that problem in very different ways. | Aspect | Higher-Order C...
Q336. Does `React.memo` prevent Context consumers from re-rendering?
**No.** `React.memo` only performs a shallow comparison of a component's **props** — it has no visibility into context. If a component reads a value via `useContext`/`Con...
Q337. How would you create a reusable Context?
A **reusable Context** bundles the `createContext` call, its `Provider` (with local state/logic), and a custom hook to consume it into a single module. This hides the raw...
Q338. Why is Redux Toolkit recommended over Redux?
**Redux Toolkit (RTK)** is the official, opinionated way to write Redux logic today. It's built on top of plain Redux and re-exports its APIs, but wraps them with utiliti...
Q339. What is the difference between client state and server state?
**Client state** is data that lives entirely in the browser and is owned by the UI — it doesn't need to be synchronized with a backend. **Server state** is data that actu...
Q340. How do you prevent unnecessary Redux re-renders?
By default, `useSelector` re-renders a component whenever the **selected value's reference** changes between renders (it uses strict `===` comparison). Most unnecessary r...