Config & Ecosystem

Interview Questions: next.config.js, Turbopack, and React 19

Q1: What is Turbopack?

Concept: An incremental bundler written in Rust, designed to replace Webpack.

Benefits: It is significantly faster than Webpack, providing near-instant server startup and HMR (Hot Module Replacement), regardless of the project size.

Usage: next dev --turbo

Q2: What are some common configurations in next.config.js?

  • images.remotePatterns: Whitelist external domains for next/image.
  • redirects / rewrites: Handle URL mapping at the server level.
  • logging: Configure fetch logging for debugging caching.
  • experimental: Enable features like ppr (Partial Prerendering) or serverActions (in older versions).

Q3: How does Next.js relate to React 19?

Next.js (App Router) was the first framework to adopt the React Server Components architecture, which is a core part of React 19.

Many "Next.js features" like Server Actions, useFormStatus, and useOptimistic are actually React features that Next.js integrates and provides the server infrastructure for.