What is Next.js, and how does it differ from React? Answer: Next.js is a framework for building server-side rendered React applications. It adds support for features like server-side rendering, automatic code splitting, and static site generation, which can improve performance and SEO.

How do you use the useEffect hook in Next.js, and what are some common use cases? Answer: The useEffect hook can be used to handle side effects in function components, such as fetching data or updating the DOM. In Next.js, you can use the getStaticProps or getServerSideProps functions to fetch data before rendering the component on the server.

How do you use the useState hook in Next.js, and what are some common use cases? Answer: The useState hook can be used to manage state in function components, such as storing form input values or toggling visibility of elements. It can be used in combination with server-side rendering to provide dynamic content based on user input.

How do you create reusable components in Next.js, and what are the benefits? Answer: Reusable components in Next.js can be created using function components and props to pass data and behavior down to child components. They provide a way to encapsulate and reuse functionality across the application, which can save development time and improve maintainability.

How do you handle forms in Next.js, and what are some common techniques? Answer: Forms in Next.js can be handled using state or useRef hooks to store the values of input fields, and the onChange event to update the state when the input values change. Validation and submission can be handled using event handlers and the onSubmit event.

How do you handle authentication in Next.js, and what are some common techniques? Answer: Authentication in Next.js can be handled using client-side cookies or server-side sessions to store user credentials, and APIs or middleware to handle login/logout requests. Common techniques include using JSON Web Tokens (JWTs) or OAuth.

How do you handle errors in Next.js, and what are some common techniques? Answer: Errors in Next.js can be handled using error pages or error boundaries to catch and display errors to the user. Common techniques include using the try/catch block or using error logging services to debug issues.

How do you optimize Next.js applications for performance, and what are some common techniques? Answer: Next.js applications can be optimized for performance using techniques like code splitting, caching, and static site generation. You can also use tools like Webpack and Babel to optimize the build process, and implement lazy loading for large files.

How do you deploy Next.js applications, and what are some common techniques? Answer: Next.js applications can be deployed using services like Vercel, Heroku, or AWS. You can also deploy the application to a server or a Docker container, and use tools like Git or CI/CD pipelines to automate the deployment process.

How do you handle internationalization (i18n) in Next.js, and what are some common techniques? Answer: Internationalization in Next.js can be handled using libraries like react-intl or next-translate to support multiple languages and locales. Common techniques include using URL parameters, cookies, or browser settings to determine the user's preferred language.

What is the difference between getStaticProps and getServerSideProps in Next.js? Answer: getStaticProps is used for static site generation, and fetches data at build time. getServerSideProps is used for server-side rendering, and fetches data on every request.

How do you use the useRouter hook in Next.js, and what are some common use cases? Answer : Accessing the current route and query parameters: You can use the useRouter hook to get information about the current route and query parameters, which can be used to customize the content or behavior of your components.