The next.js interview questions and answers help you crack the interview for a better future; this blog provides information about this technology.

Next.js is a powerful and popular React framework for building server-rendered and statically-exported applications.

It was developed by the creators of React and is designed to make it easy for developers to build high-performance and scalable applications.

1. What is Next.js?

Next.js is a framework for building web applications that utilise cutting-edge tools such as Next.js,Tailwind, Radix UI, Prisma, React Query, React Hook Forms, Zod, and more; it is designed to streamline application development and provide a collection of libraries, tools, and conventions that take web development.

2. Why is Next.js so popular?

 Next.js is famous for building fast and search engine-friendly applications that utilise cutting-edge tools and conventions.

3. What are some of the features of Next.js?

Next.js includes its routing library, a compiler for transforming and minifying JavaScript code, a command line interface for building and starting the application, a node.js runtime, and pre-rendering pages and components with static data during application development.

4. What is the node.js runtime?

The node.js runtime program allows you to execute JavaScript code within a web browser on the client side or within a node.js runtime on the server; it is a crucial feature of Next.js that allows for server-side rendering or SSR, making applications faster and more search engine friendly.

5. What is static site generation?

Static site generation is a technique for pre-rendering pages and components with static data during application development; it is a fast technique used in Next.js and allows for super-fast rendering of pages and elements.

6. What is the app folder in Next.js?

The app folder in Next.js is the container for our routing system; in Next.js, we don’t have to configure and map our routes to our components; instead, we can create files and folders to represent our routes.

7.What is the favourite icon in Next.js?

The favourite icon in Next.js is a file used to represent the website’s icon that appears in the browser’s bookmarks and tabs.

8. What is the global CSS file in Next.js?

The global CSS file in Next.js is a CSS file that contains styles that apply to the entire website.

9. What is the layout file in Next.js?

The layout file in Next.js defines the website’s basic layout; it contains elements such as the header and footer.

10. What is the UI component in Next.js?

The UI (user interface) component in Next.js is a file used to define reusable UI elements such as buttons, forms, and navigation menus.

11. What are the public assets in Next.js?

The public assets in Next.js are files such as images, vector graphics, and configuration files placed in the shared folder.

12. How do you fix the styling issue with the linear gradient applied to the body element?

We will remove the background attribute and apply padding to one rim to fix the styling issue with the linear gradient applied to the body element.

13. How is routing done in Next.js?

Routing in Next.js is based on the file system, so we can create a new Users folder in the app folder; to make this publicly accessible, we should add a page file named “page dot” with the extension JS, JSX, TSX, or TypeScript.

14. What is the purpose of the React component being created?

The purpose of the React component is to be rendered when the user is at the location slash users.

15. How is the React component created?

The React component can be created using the shortcut R, A, F, C, E, which stands for React, arrow function component with an export.

16. How can navigation be implemented?

Navigation can be implemented by returning to the homepage and pressing command and P on Mac or control and P on Windows to look at files by their name; Then, an anchor on the homepage can be set, and a label can be assigned to the anchor.

17. What are the two environments for rendering components and generating HTML markup?

The two environments for rendering components and generating HTML markup are on the client within a web browser or the server within a node.js runtime; rendering components on the client is known as client site rendering or CSR, while generating components on the server is known as server site rendering or SSR.

18. What is client site rendering and server site rendering?

Client site rendering involves redownloading all resources which exposes sensitive data to the client; in contrast, server site rendering only sends essential components to the client, preventing the bundle from becoming unnecessarily large and keeping sensitive data on the server.

19. When should we use server components and client components?

We should default to server components and use client components only when needed, client components have interactivity and can handle browser events, but server components require fewer resources on the client and prevent sensitive data from being exposed.

20. What is Next.JS, and how does it differ from standard React applications?

Next.js is a framework for building server-rendered React applications and differs from standard React applications by keeping all components on the server and minimising the bundle size.

21. What is a server component, and what are its limitations?

A server component is a React component that cannot have interactivity, so it cannot handle browser events like click and change; it helps minimise the bundle size and prevent sensitive data from being exposed to the client.

22. What is the client directive?

The client directive converts part of a server component to a client component.

23. What is a client component?

A client component is a JavaScript component that is dependent on other components. If it is dependent on them, it will be automatically included in the JavaScript bundle.

24. What is the purpose of rendering components on the server?

Rendering components on the server makes applications faster and more search engine friendly. By rendering complex markup on the server, we can reduce the amount of work that needs to be done on the client side.

25. What is the use of the client directive?

The client directive is used to move a button or other element from one component to another. In this context, it moves the button to a new component.

26. What is the difference between client and server components?

Client components are rendered on the client side, while server components are generated on the server side; the main difference is where the rendering happens.

27. What is the use of JSON placeholders?

JSON placeholders are fake APIs that can fetch dummy data into an application, they commonly test and prototype applications without needing a real API.

28. How do you fetch data on the client side?

On the client side, data is typically fetched using the state hook to declare a state variable and the effect hook to call it back get the data and put it into the state variable.

29.How do you fetch data on the server side?

On the server side, data can be fetched using the fetch function to send HTTP requests to the back end; the response is then awaited to get the data.

30. What is the use of an interface or type?

An interface or type defines the shape of data or objects; it is used to determine the shape of user objects, simplifying the code and making it easier to work.

31. What is the use of TypeScript?

TypeScript is used to provide auto-completion when coding and to cache any errors at build time before running and deploying the application; this makes it easier to catch mistakes early and reduces the amount of work needed on the client side.

32. What is the difference between typical React applications and the approach?

In typical React applications, the browser initially gets a blank document and then calls the backend to fetch the data; in contrast, in the approach, rendering is happening on the server and all users are rendered right here as rendering is happening on the server.

33. How does using JSON placeholders help simplify code and ensure application security?

Using JSON placeholders simplifies code by reducing the number of state and effect hooks required; it also ensures the application is well-designed and secure by avoiding the issues associated with manually fetching data on the client and server components.

34. What is the data cache in Next.js, and how does it help in performance optimisation?

The data cache in Next.js stores data in a location that is faster to access, which helps in more immediate data access and faster content rendering; following JS automatically stores the result of fetch requests in a data cache, which can be controlled by users to prevent caching or to keep data fresh for a particular time.

35. What is static rendering in Next.js, and how does it help optimise performance?

Static rendering in next.js means rendering pages or components with static data once when building the production application; Next.js will not re-render them when needed but will retrieve their payload or content from its cache, which is based on the file system.

This is static rendering, meaning rendering at build time, and it helps in performance optimisation by reducing the number of requests to the server and improving load times.

36. What is the difference between static rendering and dynamic rendering in Next.js?

Static rendering in Next.js means rendering pages or components that have static data once when building the production application, and dynamic rendering happens at request time, where Next.js decides to render a page or component based on the request and the data that is needed to render it.

Dynamic rendering can be helpful for pages or components with dynamic data changes frequently.

37. What performance optimization techniques does Next.js offer?

Next.js offers several performance optimisation techniques, including caching, static, and dynamic rendering.

38. What is caching Next.js?

Caching Next.js is a technique that stores frequently accessed data in memory or on disk to reduce the number of requests to the server.

39. What is static rendering in Next.js?

Static rendering in Next.js refers to a technique that renders a web page on the server at build time, improving performance and making the page more search engine-friendly.

40. What is dynamic rendering in Next.js?

Dynamic rendering in Next.js refers to a technique that renders a web page on the server at request time, which is more flexible than static rendering but can be slower.

41. What is the difference between server-side rendering and client-side rendering?

Server-side rendering (SSR) refers to rendering a web page on the server at the request time, while client-side rendering (CSR) refers to rendering a web page on the client’s browser.

42. What is the purpose of global styles in Next.js?

Global styles in Next.js define truly global styles in the application, such as body elements, headings, hyperlinks, and more, any styles specific to a page or component should be implemented elsewhere.

43. What are CSS modules in Next.js?

CSS modules in Next.js are CSS files scoped to a page or component to prevent styles from clashing or overwriting each other; they aim to solve the problem of having the same class defined in two different places in two different style sheets.

44. What is the purpose of using CSS modules in Next.js?

The purpose of using CSS modules in Next.js is to prevent styles from clashing or overwriting each other and to make maintaining the application’s style easier.

45. What is the difference between global styles and CSS modules in Next.js?

Global styles in Next.js define truly global styles in the application, while CSS modules define styles scoped to a page or component.

46. What is the purpose of using tailwind in Next.js?

Tailwind is a popular CSS framework that can be used in Next.js to quickly and easily style components; it provides a set of pre-defined styles that can be easily customised and combined to create unique styles.

47. What is the purpose of using the Daz user interface in Next.js?

The Daz user interface is a customisable user interface component library used in Next.js to create visually appealing and functional applications; it provides a set of pre-defined components that can be easily customised and combined to create unique interfaces.

48. What is the purpose of setting the class name to style dot cards on a component?

Setting the class name to style dot cards on a component creates a class with curly braces and a unique class name that doesn’t clash with the class we created; this is done using a post-CSS tool for transforming class names.

49. What is post-CSS, and what is its role in the development process?

Post CSS is a tool for transforming class names and generating unique names that don’t clash; it is used in the development process to ensure that class names are unique and don’t affect the application’s functionality.

50. What is the file called post-CSS dot config.js, and what does it contain?

The file is called post-CSS dot config.js and contains two plugins: tailwind and auto prefix. Advanced users can provide their custom configurations for this file; when building an application, Next.js uses post-CSS to transform class names and generate unique class names that don’t clash.

51. What is the purpose of creating a folder like a product card for CSS and TSX files?

Creating a folder-like product card for CSS and TSX files allows us to group our files and define styles local to a particular page; it enables us to create styles specific to our component, making it easier to maintain and update our application.

52. What is Tailwind, and what are its features?

Tailwind is a popular CSS framework that uses the concept of utility classes; it offers a ton of small utility classes that can be combined to store our application; Tailwind has various classes for different purposes, such as padding-top, padding-right, padding-bottom, and padding-left.

It also has classes for styling text, controlling size, and applying colors, the default color palette comes with a Tailwind, which includes beautiful colours that can be customized to fit your brand.

53. What are the classes for margins in Tailwind?

We have similar classes for margins, but start with m followed by a number; the classes for margins in Tailwind are mx, my, ml, mr, mt, and mb.

54. What is the use of CSS modules in JavaScript and CSS?

The use of CSS modules in JavaScript and CSS is essential for creating visually appealing and functional applications; it allows developers to define styles locally, reducing the amount of code required and improving the application’s performance; CSS modules also make it easier to maintain and update the styles used in the application.

55.What is the benefit of using Tailwind?

One of the main benefits of using Tailwind is that it eliminates the need to clean up when changing or deleting components and CSS modules; developers must remember to delete the CSS file, which can be a challenge if the element is deleted.

56. What is Daisy UI?

Daisy UI is another popular component library for Tailwind, similar to Bootstrap for Tailwind; it provides a variety of components, such as accordions, alerts, red crumbs, buttons, cards, carousels, and chat bubbles.

57. How do you create a table with two columns: user name and user email?

To create a table with two columns: user name and user email by using HTML and adding the necessary elements such as head, TR, and two TH elements.

58. How can you improve the overall appearance of your application using Daisy UI?

To improve the overall appearance of your application, use Daisy UI by adding the necessary classes and applying them to the table, you can also use the Daisy UI plugin to create visually appealing and functional user interfaces.

59. What is the purpose of creating an app folder in Next Jazz?

The app folder contains all of the application’s code and is where all of the applications will exist.

60. What is the default boilerplate code for creating an app in Next Jazz?

The default boilerplate code for creating an app in Next Jazz is standard.

61. How do you create new routes in an application using Next Jazz?

To create new routes in an application, one can delete existing files and create a new folder called, this folder contains a file called page.tsx, which is used to identify the page as a route.

The folder determines the route’s name, and the function name is exported as “page” or “about” Users can call these functions “page” or “about” to make it easier.

62. How can nested routes be created?

Nested routes can be created by creating a new folder called “new” inside the user folder and adding a new page file; then, a React component can be created and reach the new user page.

For example, to have a website with an about page that can be about us or someone else, one could create a folder called “about” and create two different routes that are extensions of the about route.

63. What is the difference between Next Jazz and Webpack?

Next Jazz is a powerful and fast language that offers numerous improvements and features over Webpack; it is faster than Webpack and provides more flexibility for developers who want to build fast and efficient applications, it may become difficult for developers to adapt to Turbopack and Rust due to its familiarity with Webpack and its unfamiliarity with Turbopack.

64. What is the difference between client and server components in React?

A client component acts as an intermediate between the user and the actual client, allowing for browsing events, hooks, and logic, on the other hand, server components allow rendering components in the server, reducing the amount of JavaScript sent to the client and loaded in the client.

65. What is the importance of layouts in establishing the structure of a website in Next Jazz?

Layouts are essential in establishing the structure of a website in Next Jazz because they determine how the different routes are displayed on the website; there are several routes, including about us, about us, and about someone, which can’t be accessed if they are on the homepage.

A simple navbar component would be created to display these routes, which would be exported and filled with links from next.js, these links would be imported into the navbar component, which would be used to display the navbar inside every element.

66. How do you display the navbar above all other routes in Next Jazz?

To display the navbar above all other routes in Next Jazz, one would need to import the navbar component from next.js and import it into the navbar component; this would allow the navbar to be accessible in every single route in the routing system.

67. What is the layout.tsx file and what is its purpose?

The layout.tsx file is a function that determines how a website’s actual HTML is structured, its purpose is to display all children, or all routes, within the file.

68. How does a navbar affect the functionality of a website?

A navbar that is always visible and accessible can maintain the structure and functionality of a website.

69. What is Next.js, and why is it popular among developers?

Next.js is a popular choice for developers due to its ability to facilitate server-side rendering, which allows search engines to find your website and improves efficiency.

70. How can data be fetched from a server component without using the previous notation in Next.js?

To fetch data from a server component without using the previous notation in Next.js, we can create a function called “get posts, data” and make it asynchronous, this is done by using the fetch API function and passing the response as a parameter.

71. How do you create a nested route in Next Jazz?

To create a nested route, one can create a folder called “about” and create two different routes that are extensions of the about route.

72. What is the advantage of using server components in web development?

Server components have several advantages over client components, including improved functionality, notation, and a more efficient approach to data fetching, by making the A P I function asynchronous, we can access data within our applications and improve our overall user experience.

73. What are some limitations of using server components in web development?

Server components cannot have browser functionality and cannot put a button or use event handlers to pass to client component props because they are inside a server component.

They also cannot work around these limitations by using event handlers, use effect, use state, or any client-side hook from react inside these components.

74. What is the difference between using a static API and a dynamic API?

A static API is an API that returns the same data every time it is accessed, while a dynamic API is an API that returns different data each time it is accessed.

75. How can a client component be used to fetch data in React?

A client component can fetch data in React by using error and loading components, these components can be used to display customised messages when there is an error in APIs and to ensure that the data is updated regularly without overloading the server.

76. How to add a loading component in React?

A loading component can also be added, like loading.tsx, which can be copied from the error page and pasted over the loader; the loading component will take longer than the error component, so it must be cached every time.

77. What is revalidation?

Revalidation is a property in XDS that allows users to reevaluate the request at a specific interval; it can be used to ensure that data is updated regularly without overloading the server.

78.What are the benefits of using client components in React?

There are benefits to using client components, such as helping with next-generation applications and reactions; they will stay in place for a long time, but it is essential to understand when and where to use them.

79. What are the rules when using server and client components in React?

When using server and client components in React, first rule is that you cannot import a server component into a client component, but you can pass a server component as a prop or child to a client component.

Conclusion

Next.js is a popular and powerful React framework that is used for building server-rendered and statically-exported applications; it was developed by the creators of React and is designed to make it easy for developers to build high-performance and scalable applications

In this blog, we will explore some common interview questions related to Next.js that you may encounter during a job interview; these questions will help you to demonstrate your knowledge and understanding of the framework and will allow you to showcase your skills and experience to potential employers.