Real-World Next.js Interview Questions Challenge Quiz Quiz

Sharpen your understanding of real-world Next.js concepts with this interview-focused quiz designed to evaluate key knowledge areas, including data fetching methods, routing strategies, middleware, and page optimization. Perfect for candidates aiming to demonstrate proficiency in modern web application development using Next.js best practices.

1. Understanding Data Fetching Choices

   In a Next.js project requiring server-side authentication for each request, which data fetching method is most appropriate for a page showing user-specific dashboard information?

   1. getStaticProps
   2. getInitialProps
   3. useEffect with fetch
   4. getServerSideProps

   Explanation: getServerSideProps is executed on the server for every request, enabling dynamic authentication and personalized data fetching for each user session. getStaticProps generates static pages at build time, making it unsuitable for personalized content. useEffect with fetch runs on the client side, leading to data visibility issues before client scripts load. getInitialProps is now less commonly recommended and also can have suboptimal performance and compatibility.

2. Dynamic Routing Techniques

   Which filename in the 'pages' directory is required to create a dynamic route that matches URLs like '/blog/my-first-post' in Next.js?

   1. _slug.js
   2. [slug].js
   3. [id].html
   4. slug.js

   Explanation: Files named with square brackets, like [slug].js, enable dynamic routing by capturing route parameters in Next.js. slug.js would only match '/blog/slug' literally, not dynamic segments. [id].html is not valid in the pages directory and would not work for dynamic routes. _slug.js does not enable dynamic segments—underscore files are reserved for other purposes.

3. API Routes Behavior

   Suppose you add a file called 'hello.js' inside a project's 'pages/api' directory; what is the expected behavior when accessing '/api/hello'?

   1. It executes a serverless function and returns a response
   2. It triggers a client-side navigation to another route
   3. It renders a static HTML page for the route
   4. It loads an external resource using fetch

   Explanation: Placing a file in pages/api creates an API route that runs code on the server, treating the file as a serverless function responding to HTTP requests. It does not create a static HTML page; those are only generated in the regular pages directory. Client-side navigation is unrelated to API route access, and the file does not automatically perform fetch requests for external data unless explicitly coded.

4. Optimizing Performance with Static Generation

   A marketing site needs high performance and rarely changes, but updates should show after the next deployment. Which rendering approach provides optimal performance for this scenario?

   1. Client-side Fetching with useEffect
   2. Static Generation with getStaticProps
   3. Server-side Rendering with getServerSideProps
   4. Incremental Static Regeneration with getServerSideProps

   Explanation: Static Generation with getStaticProps builds the site at deployment time for fast, cacheable pages, ideal for infrequently updated marketing content. Server-side Rendering generates pages at each request, causing unnecessary overhead for rarely changing sites. Client-side fetching delays content display until client rendering. Incremental Static Regeneration relies on getStaticProps, not getServerSideProps, so that option is inaccurate.

5. Middleware Use Cases

   Which of these scenarios is the best fit for using Next.js middleware in an application?

   1. Rendering client-only interactive widgets
   2. Fetching data for populating a page at build time
   3. Redirecting users based on authentication before rendering protected routes
   4. Defining catch-all API routes for dynamic segments

   Explanation: Next.js middleware runs before rendering and is ideal for tasks like authentication-based redirects, as it can control routing at the edge. Data fetching at build time does not use middleware but uses getStaticProps. Rendering client-only widgets is done on the client side with hooks and components, not middleware. Defining catch-all API routes is unrelated to middleware, handled by file naming conventions.