To use the Link component, you simply need to import it from the next/link package and use it in your code. For example, the following code will render a link to the /about route:

<Link href="/about">About</Link>

When the user clicks on the link, they will be navigated to the /about route.

The Link component has a number of props that you can use to customize its behavior. For example, you can use the prefetch prop to prefetch the resources for the target route before the user clicks on the link. This can improve the perceived performance of your application by making it appear more responsive.

Here is an example of how to use the prefetch prop:

<Link href="/about" prefetch>About</Link>

This code will prefetch the resources for the /about route before the user clicks on the link.

You can also use the as prop to change the text that is displayed in the link. For example, the following code will render a link to the /about route, but the text that is displayed will be “Contact Us”:

<Link href="/about" as="Contact Us">About</Link>

The Link component is a powerful tool that can be used to handle client-side routing in Next.js. It is easy to use and provides a number of features that can improve the performance and usability of your application.

Creating nested routing structures with the Next.js router

Next.js routing is file-system based, which means that you can create nested routes by creating subdirectories in your pages directory. For example, to create a route for /about/contact, you would create a directory called about inside the pages directory, and then create a file called contact.js inside the about directory.

The about/contact route would be accessible at the URL /about/contact.

You can also use dynamic routing in Next.js to create routes that are based on parameters. For example, to create a route for /about/:name, you would use the :name placeholder in the route path. The :name placeholder would be replaced with the value of the name query parameter when the route is navigated to.

The about/:name route would be accessible at the URL /about/<name>, where <name> is the value of the name query parameter.

Next.js routing is a powerful tool that can be used to create complex and flexible routing structures. It is easy to use and provides a number of features that can improve the performance and usability of your application.

Here are some tips for creating nested routing structures with the Next.js router:

• Use descriptive names for your routes. This will make it easier for you to find and understand your routes later on.
• Use the getStaticProps and getStaticPaths functions to pre-render your pages. This can improve the performance of your application by reducing the number of requests that are made to the server.
• Use the useRouter hook to access the current route in your components. This can be useful for things like displaying the current page title or checking the current user’s permissions.
• Use the Link component to handle client-side navigation between routes. This can improve the performance of your application by making it appear more responsive.

If you follow these tips, you should be able to create nested routing structures with the Next.js router without any problems.

Passing data between pages in Next.js with query parameters and state management techniques

There are a few different ways to pass data between pages in Next.js.

One way is to use query parameters. Query parameters are the values that are appended to the URL of a page. For example, the URL /about?name=John has a query parameter called name with the value John.

To pass data using query parameters, you simply need to add the data to the URL of the page. For example, to pass the name John to the /about page, you would use the following URL:

/about?name=John

The data in the query parameters will be available to the page as a prop called query. For example, the following code will render the text “Hello, John!” on the /about page:

const About = () => {
  const { query } = useRouter();

  return (
    <div>
      Hello, {query.name}!
    </div>
  );
};

Another way to pass data between pages in Next.js is to use state management techniques. State management techniques allow you to store data in the application state. This data can then be accessed by any component in the application.

There are a number of different state management techniques that you can use in Next.js. Some popular state management techniques include Redux, Recoil, and Zustand.

To pass data using state management techniques, you simply need to store the data in the application state. For example, to store the name John in the application state, you would use the following code:

const state = {
  name: 'John',
};

The data in the application state can then be accessed by any component in the application. For example, the following code will render the text “Hello, John!” on any component:

const Component = () => {
  const { name } = useState();

  return (
    <div>
      Hello, {name}!
    </div>
  );
};

Which method you use to pass data between pages in Next.js depends on your specific needs. If you need to pass a small amount of data, then using query parameters is a good option. If you need to pass a large amount of data or if you need to share data between multiple components, then using state management techniques is a better option.

Customizing the default behavior of the Next.js router using advanced routing techniques

There are a number of ways to customize the default behavior of the Next.js router.

One way to customize the default behavior of the Next.js router is to use the useRouter hook. The useRouter hook provides access to the current route, the history, and the location. You can use this information to customize the behavior of the router.

For example, you can use the useRouter hook to prevent users from navigating to certain routes. You can also use the useRouter hook to redirect users to different routes.

Another way to customize the default behavior of the Next.js router is to use the onRouteChange event. The onRouteChange event is fired whenever the route changes. You can use this event to perform custom actions when the route changes.

For example, you can use the onRouteChange event to update the application state. You can also use the onRouteChange event to fetch new data from the server.

Finally, you can also customize the default behavior of the Next.js router by using the next.config.js file. The next.config.js file is a configuration file that allows you to customize the behavior of Next.js.

For example, you can use the next.config.js file to change the default 404 page. You can also use the next.config.js file to configure the router.

Here are some tips for customizing the default behavior of the Next.js router:

• Use the useRouter hook to access the current route, the history, and the location.
• Use the onRouteChange event to perform custom actions when the route changes.
• Use the next.config.js file to customize the behavior of Next.js.

If you follow these tips, you should be able to customize the default behavior of the Next.js router without any problems.

Building complex routing systems with Next.js and dynamic route matching

Next.js is a React framework that makes it easy to build server-rendered and static web applications. It also provides a powerful routing system that can be used to create complex routing structures.

Dynamic route matching is a feature of the Next.js router that allows you to match routes based on dynamic values. For example, you can use dynamic route matching to match routes based on the current user’s id, the current date, or the current time.

To use dynamic route matching, you simply need to use the : character in the route path. The : character is replaced with the value of the dynamic value when the route is matched.

For example, the following route matches the /users/:id path:

/users/:id

The :id placeholder is replaced with the value of the id query parameter when the route is matched.

You can also use dynamic route matching with the getStaticProps and getStaticPaths functions. The getStaticProps and getStaticPaths functions allow you to pre-render pages at build time. This can improve the performance of your application by reducing the number of requests that are made to the server.

To use dynamic route matching with the getStaticProps and getStaticPaths functions, you simply need to use the : character in the route path. The : character is replaced with the value of the dynamic value when the functions are called.

For example, the following code uses the getStaticProps function to pre-render the /users/:id page at build time:

const getStaticProps = ({ params }) => {
  const { id } = params;

  // Fetch the user from the database
  const user = await fetch(`/api/users/${id}`);

  // Return the props that will be passed to the page
  return {
    props: {
      user,
    },
  };
};

export default function Users({ user }) {
  // Render the page with the user data
  return (
    <div>
      <h1>User {user.name}</h1>
    </div>
  );
}

The getStaticProps function is called once at build time. The user object is then passed to the Users component. The Users component renders the page with the user data.

Here are some tips for building complex routing systems with Next.js and dynamic route matching:

• Use descriptive names for your routes. This will make it easier for you to find and understand your routes later on.
• Use the getStaticProps and getStaticPaths functions to pre-render your pages. This can improve the performance of your application by reducing the number of requests that are made to the server.
• Use the useRouter hook to access the current route in your components. This can be useful for things like displaying the current page title or checking the current user’s permissions.
• Use the Link component to handle client-side navigation between routes. This can improve the performance of your application by making it appear more responsive.

If you follow these tips, you should be able to build complex routing systems with Next.js and dynamic route matching without any problems.

Implementing user authentication and authorization with Next.js and protected routes

Next.js is a React framework that makes it easy to build server-rendered and static web applications. It also provides a powerful authentication and authorization system that can be used to protect your application’s routes.

To implement user authentication and authorization with Next.js, you will need to:

1. Create a user model.
2. Create a user authentication service.
3. Create a user authorization service.
4. Protect your routes.

Here are the steps in more detail:

1. Create a user model.

The user model is a JavaScript object that represents a user. It should include the following properties:

• id: The user’s unique identifier.
• name: The user’s name.
• email: The user’s email address.
• password: The user’s password.

2. Create a user authentication service.

The user authentication service is responsible for authenticating users. It should include the following methods:

• signUp: This method is used to create a new user.
• signIn: This method is used to sign in a user.
• signOut: This method is used to sign out a user.

3. Create a user authorization service.

The user authorization service is responsible for authorizing users. It should include the following methods:

• canAccessRoute: This method is used to check if a user has permission to access a given route.

4. Protect your routes.

To protect your routes, you can use the useAuth hook. The useAuth hook provides access to the current user’s authentication state. You can use this information to protect your routes.

For example, the following code protects the /admin route from unauthorized users:

const AdminPage = () => {
  // Check if the user is authenticated
  const { isAuthenticated } = useAuth();

  // If the user is not authenticated, redirect them to the login page
  if (!isAuthenticated) {
    return <Redirect to="/login" />;
  }

  // The user is authenticated, so render the page
  return (
    <div>
      <h1>Admin Page</h1>
    </div>
  );
};

If you follow these steps, you should be able to implement user authentication and authorization with Next.js and protected routes without any problems.

Creating dynamic navigation menus with Next.js and server-side data fetching

here are the steps on how to create dynamic navigation menus with Next.js and server-side data fetching:

1. Create a data.js file in the pages directory. This file will contain the data for the navigation menu.
2. In the data.js file, define an array of objects. Each object will represent a menu item.
3. The menuItem objects should have the following properties:
   • label: The label of the menu item.
   • to: The path of the page that the menu item will link to.
   • active: A Boolean value that indicates whether the menu item is active.
4. In your _app.js file, import the data.js file and use the getServerSideProps function to fetch the data from the server.
5. In the getServerSideProps function, call the fetch method to fetch the data from the server.
6. The fetch method will return a promise. When the promise resolves, the data property of the response object will contain the data for the navigation menu.
7. In the getServerSideProps function, return the data for the navigation menu.
8. In your App component, use the useRouter hook to access the current route.
9. In the App component, use the useState hook to store the active menu item.
10. In the App component, use the useEffect hook to update the active menu item when the route changes.
11. In the App component, render the navigation menu.

Here is an example of how to create a dynamic navigation menu with Next.js and server-side data fetching:

// data.js

const data = [
  {
    label: "Home",
    to: "/",
    active: true,
  },
  {
    label: "About",
    to: "/about",
  },
  {
    label: "Contact",
    to: "/contact",
  },
];

// _app.js

import data from "../data";

export default function App() {
  const { currentRoute } = useRouter();
  const [activeMenuItem, setActiveMenuItem] = useState(data[0]);

  useEffect(() => {
    setActiveMenuItem(data.find((item) => item.to === currentRoute));
  }, [currentRoute]);

  return (
    <div>
      <h1>My App</h1>
      <nav>
        {data.map((item) => (
          <Link
            key={item.label}
            href={item.to}
            activeClassName="active"
          >
            {item.label}
          </Link>
        ))}
      </nav>
      <main>
        {activeMenuItem.label}
      </main>
    </div>
  );
}

This code will create a dynamic navigation menu with three menu items: Home, About, and Contact. The Home menu item will be active by default. When the user navigates to a different page, the active menu item will be updated.

Building SEO-friendly Next.js apps with dynamic meta tags and server-side rendering.

Here are some tips on how to build SEO-friendly Next.js apps with dynamic meta tags and server-side rendering:

1. Use the getStaticProps and getStaticPaths functions to pre-render your pages. This will improve the performance of your application by reducing the number of requests that are made to the server.
2. Use the Head component to add dynamic meta tags to your pages. This will allow you to control the meta tags for your pages without having to modify the HTML markup.
3. Use the Link component to handle client-side navigation between your pages. This will improve the performance of your application by making it appear more responsive.
4. Use the useRouter hook to access the current route in your components. This can be useful for things like displaying the current page title or checking the current user’s permissions.
5. Use the useQuery hook to fetch data from the server on demand. This will improve the performance of your application by reducing the number of requests that are made to the server.

Here are some additional tips:

• Use descriptive names for your pages and routes. This will make it easier for search engines to understand your content.
• Use relevant keywords in your page titles and meta descriptions. This will help your pages rank higher in search results.
• Use canonical URLs for your pages. This will help search engines understand the relationship between your pages.
• Submit your sitemap to Google Search Console. This will help Google index your pages.
• Monitor your site’s SEO performance in Google Search Console. This will help you identify any areas where you can improve your SEO.

If you follow these tips, you should be able to build SEO-friendly Next.js apps with dynamic meta tags and server-side rendering.

Chapter 3: Data Fetching in Next.js

Server-side rendering vs. client-side rendering

Server-side rendering (SSR) is a technique for generating the HTML for a web page on the server before it is sent to the client. This means that the client does not have to do any work to render the page, which can improve the performance of the page.

Client-side rendering (CSR) is a technique for generating the HTML for a web page on the client after it is loaded. This means that the client has to do some work to render the page, which can slow down the page load time.

There are a number of factors to consider when choosing between SSR and CSR, including:

• Performance: SSR can improve the performance of a web page by reducing the amount of work that the client has to do.
• SEO: SSR can improve the SEO of a web page by making it easier for search engines to index the content of the page.
• Control: SSR gives you more control over the content of the page, as you can generate the HTML on the server before it is sent to the client.
• Complexity: SSR can be more complex to implement than CSR, as you need to generate the HTML on the server.

Ultimately, the best choice for you will depend on your specific needs and requirements. If you are concerned about performance or SEO, then SSR may be a good choice for you. If you are concerned about complexity, then CSR may be a better choice.

Types of data fetching in Next.js

Next.js provides a number of different ways to fetch data from the server. The type of data fetching that you use will depend on your specific needs and requirements.

Server-side data fetching (SSR)

Server-side data fetching is the process of fetching data from the server before the page is rendered. This means that the data is available to the page when it is first loaded, which can improve the performance of the page.

To use server-side data fetching, you can use the getServerSideProps or getStaticProps functions. The getServerSideProps function is called on every request, while the getStaticProps function is only called when the page is first built.

Client-side data fetching (CSR)

Client-side data fetching is the process of fetching data from the server after the page has been loaded. This means that the page will be loaded without the data, which can slow down the page load time.

To use client-side data fetching, you can use the useQuery hook. The useQuery hook provides a way to fetch data from the server and update the state of your component when the data is fetched.

Incremental static regeneration (ISR)

Incremental static regeneration is a technique for combining server-side data fetching and client-side data fetching. ISR is a good choice if you want to improve the performance of your page without sacrificing SEO.

To use ISR, you can use the getStaticPaths and getStaticProps functions. The getStaticPaths function is used to determine the paths that will be pre-rendered, and the getStaticProps function is used to fetch the data for the pre-rendered pages.

Dynamic data fetching

Dynamic data fetching is the process of fetching data from the server based on the current state of your application. This can be useful for things like fetching user data, fetching product data, or fetching search results.

To use dynamic data fetching, you can use the useQuery hook. The useQuery hook provides a way to fetch data from the server and update the state of your component when the data is fetched.

Which type of data fetching should you use?

The type of data fetching that you use will depend on your specific needs and requirements. If you are concerned about performance, then server-side data fetching or ISR may be a good choice for you. If you are concerned about SEO, then server-side data fetching may be a good choice for you. If you need to fetch data based on the current state of your application, then dynamic data fetching may be a good choice for you.

Ultimately, the best choice for you will depend on your specific needs and requirements.

Fetching data during page rendering

There are a few different ways to fetch data during page rendering in Next.js.

Use the useQuery hook

The useQuery hook is a great way to fetch data during page rendering. It provides a way to fetch data from the server and update the state of your component when the data is fetched.

To use the useQuery hook, you need to import it from react-query. Then, you can use it in your component like this:

import { useQuery } from "react-query";

const MyComponent = () => {
  const { isLoading, data, error } = useQuery("myQuery", () => {
    // Fetch data from the server here.
  });

  if (isLoading) {
    // Do something while the data is loading.
  } else if (error) {
    // Handle the error here.
  } else {
    // Use the data here.
  }

  return (
    <div>
      {data && <h1>{data.title}</h1>}
    </div>
  );
};

Use the getStaticProps or getStaticPaths functions

The getStaticProps and getStaticPaths functions are great ways to fetch data during build time. This means that the data will be available when the page is first loaded, which can improve the performance of the page.

To use the getStaticProps or getStaticPaths functions, you need to export them from your page’s _app.js file. Then, you can use them to fetch data from the server like this:

export default function App() {
  const { data } = useStaticProps();

  return (
    <div>
      {data && <h1>{data.title}</h1>}
    </div>
  );
}

export const getStaticProps = async () => {
  // Fetch data from the server here.
  const data = await fetch("/api/data");

  return {
    props: {
      data,
    },
  };
};

Use the useEffect hook

The useEffect hook is a great way to fetch data when a component mounts or updates. It provides a way to run code when a component is mounted or updates, and it can be used to fetch data from the server.

To use the useEffect hook, you need to import it from react. Then, you can use it in your component like this:

import { useEffect } from "react";

const MyComponent = () => {
  const [data, setData] = useState();

  useEffect(() => {
    // Fetch data from the server here.
    fetch("/api/data")
      .then((response) => response.json())
      .then((data) => setData(data));
  }, []);

  return (
    <div>
      {data && <h1>{data.title}</h1>}
    </div>
  );
};

Ultimately, the best way to fetch data during page rendering will depend on your specific needs and requirements.

Fetching data after page rendering

There are a few different ways to fetch data after page rendering in Next.js.

Use the useQuery hook

The useQuery hook is a great way to fetch data after page rendering. It provides a way to fetch data from the server and update the state of your component when the data is fetched.

To use the useQuery hook, you need to import it from react-query. Then, you can use it in your component like this:

import { useQuery } from "react-query";

const MyComponent = () => {
  const { isLoading, data, error } = useQuery("myQuery", () => {
    // Fetch data from the server here.
  });

  if (isLoading) {
    // Do something while the data is loading.
  } else if (error) {
    // Handle the error here.
  } else {
    // Use the data here.
  }

  return (
    <div>
      {data && <h1>{data.title}</h1>}
    </div>
  );
};

Use the useEffect hook

The useEffect hook is a great way to fetch data after a component mounts or updates. It provides a way to run code when a component is mounted or updates, and it can be used to fetch data from the server.

To use the useEffect hook, you need to import it from react. Then, you can use it in your component like this:

import { useEffect } from "react";

const MyComponent = () => {
  const [data, setData] = useState();

  useEffect(() => {
    // Fetch data from the server here.
    fetch("/api/data")
      .then((response) => response.json())
      .then((data) => setData(data));
  }, []);

  return (
    <div>
      {data && <h1>{data.title}</h1>}
    </div>
  );
};

Use the useInterval hook

The useInterval hook is a great way to fetch data from the server at regular intervals. It provides a way to run code at regular intervals, and it can be used to fetch data from the server.

To use the useInterval hook, you need to import it from react-use. Then, you can use it in your component like this:

import { useInterval } from "react-use";

const MyComponent = () => {
  const [data, setData] = useState();

  useInterval(() => {
    // Fetch data from the server here.
    fetch("/api/data")
      .then((response) => response.json())
      .then((data) => setData(data));
  }, 1000); // Fetch data every second.

  return (
    <div>
      {data && <h1>{data.title}</h1>}
    </div>
  );
};

Ultimately, the best way to fetch data after page rendering will depend on your specific needs and requirements.

Using getStaticProps to pre-render pages at build time

The getStaticProps function is a great way to pre-render pages at build time. It allows you to fetch data from the server and generate the HTML for the page during build time, which can improve the performance of the page.

To use the getStaticProps function, you need to export it from your page’s _app.js file. Then, you can use it to fetch data from the server like this:

export default function App() {
  const { data } = useStaticProps();

  return (
    <div>
      {data && <h1>{data.title}</h1>}
    </div>
  );
}

export const getStaticProps = async () => {
  // Fetch data from the server here.
  const data = await fetch("/api/data");

  return {
    props: {
      data,
    },
  };
};

When the page is built, the getStaticProps function will be called and the data will be fetched from the server. The HTML for the page will then be generated using the data that was fetched.

When the page is requested, the HTML for the page will be served directly from the cache, which can improve the performance of the page.

The getStaticProps function can be used to pre-render any page in your Next.js application. It is a great way to improve the performance of your application and make it more responsive.

Incremental Static Regeneration (ISR) in Next.js

Incremental static regeneration (ISR) is a technique for generating static pages on demand. It is a hybrid of server-side rendering (SSR) and client-side rendering (CSR).

With ISR, pages are generated on the server when they are first requested. However, if the page is updated, the server will not regenerate the entire page. Instead, the server will only regenerate the parts of the page that have changed. This can improve the performance of your application by reducing the amount of work that the server has to do.

ISR is a great choice for pages that are updated frequently, such as blog posts and news articles. It can also be used for pages that are personalized for each user, such as product pages and user profiles.

To use ISR, you need to use the getStaticProps or getStaticPaths functions with the revalidate prop. The revalidate prop specifies the number of seconds after which the page should be regenerated.

For example, the following code will generate a static page for the /about route and regenerate the page every 60 seconds:

export const getStaticProps = ({ revalidate }) => {
  // Fetch data from the server here.
  const data = await fetch("/api/data");

  return {
    props: {
      data,
    },
    revalidate: 60,
  };
};

When the page is requested, the getStaticProps function will be called and the data will be fetched from the server. The HTML for the page will then be generated using the data that was fetched.

If the page is updated within 60 seconds, the server will regenerate the page and the new version of the page will be served to the user.

ISR is a great way to improve the performance of your application and make it more responsive. It is a powerful technique that can be used to improve the performance of a wide variety of pages.

Static Site Generation (SSG) in Next.js

Static Site Generation (SSG) is a technique for generating static pages at build time. This means that the pages are generated before they are served to the user, which can improve the performance of the application.

To use SSG in Next.js, you need to use the getStaticProps function. The getStaticProps function is a lifecycle hook that is called when the page is built. It can be used to fetch data from the server and generate the HTML for the page.

For example, the following code will generate a static page for the /about route:

export const getStaticProps = async () => {
  // Fetch data from the server here.
  const data = await fetch("/api/data");

  return {
    props: {
      data,
    },
  };
};

When the page is built, the getStaticProps function will be called and the data will be fetched from the server. The HTML for the page will then be generated using the data that was fetched.

When the page is requested, the HTML for the page will be served directly from the cache, which can improve the performance of the page.

SSG is a great way to improve the performance of your application. It is especially useful for pages that are not frequently updated, such as blog posts and product pages.

Here are some of the benefits of using SSG in Next.js:

• Improved performance: Pages are generated at build time, so they can be served directly from the cache, which can improve the performance of your application.
• SEO friendly: Pages are generated with SEO in mind, so they can be indexed by search engines.
• Scalable: SSG can be used to scale your application to handle large traffic volumes.
• Easy to use: SSG is easy to use and can be integrated with any Next.js application.

Using getServerSideProps to fetch data at runtime

The getServerSideProps function is a lifecycle hook that is called when the page is requested. It can be used to fetch data from the server and update the props of the page component.

To use getServerSideProps, you need to export it from your page’s _app.js file. Then, you can use it to fetch data from the server like this:

export default function App() {
  const { data } = useServerSideProps();

  return (
    <div>
      {data && <h1>{data.title}</h1>}
    </div>
  );
}

export const getServerSideProps = async () => {
  // Fetch data from the server here.
  const data = await fetch("/api/data");

  return {
    props: {
      data,
    },
  };
};

When the page is requested, the getServerSideProps function will be called and the data will be fetched from the server. The props of the page component will then be updated with the data that was fetched.

The getServerSideProps function is a great way to fetch data from the server at runtime. It is especially useful for pages that need to be personalized for each user, such as product pages and user profiles.

Here are some of the benefits of using getServerSideProps in Next.js:

• Improved performance: Data is fetched from the server at runtime, so the page can be rendered with the latest data.
• SEO friendly: Pages are rendered with the latest data, so they can be indexed by search engines.
• Scalable: getServerSideProps can be used to scale your application to handle large traffic volumes.
• Easy to use: getServerSideProps is easy to use and can be integrated with any Next.js application.

Combining static and dynamic data fetching in Next.js

Next.js allows you to combine static and dynamic data fetching in a number of ways.

One way is to use the getStaticProps and getServerSideProps functions together. The getStaticProps function can be used to fetch static data, such as blog posts and product pages. The getServerSideProps function can be used to fetch dynamic data, such as user profiles and product reviews.

For example, the following code will generate a static page for the /about route and fetch the user’s profile data at runtime:

export const getStaticProps = async () => {
  // Fetch static data here.
  const data = await fetch("/api/data");

  return {
    props: {
      data,
    },
  };
};

export const getServerSideProps = async (context) => {
  // Fetch dynamic data here.
  const user = await fetch("/api/user", {
    headers: {
      "Authorization": context.req.headers.authorization,
    },
  });

  return {
    props: {
      user,
    },
  };
};

Another way to combine static and dynamic data fetching is to use the useQuery hook. The useQuery hook can be used to fetch dynamic data from the server and update the state of your component when the data is fetched.

For example, the following code will fetch the user’s profile data at runtime and update the state of the user variable:

const [user, setUser] = useState(null);

useEffect(() => {
  // Fetch dynamic data here.
  fetch("/api/user", {
    headers: {
      "Authorization": localStorage.getItem("token"),
    },
  })
    .then((response) => response.json())
    .then((data) => setUser(data));
}, []);

return (
  <div>
    {user && <h1>{user.name}</h1>}
  </div>
);

Finally, you can also use the useStaticQuery hook to fetch static data from the server and update the state of your component.

For example, the following code will fetch the list of blog posts from the server and update the state of the posts variable:

const [posts, setPosts] = useState([]);

useStaticQuery(() => {
  // Fetch static data here.
  const data = await fetch("/api/posts");

  return {
    posts: data.data,
  };
});

return (
  <div>
    {posts && <ul>{posts.map((post) => (
      <li key={post.id}>{post.title}</li>
    ))}</ul>}
  </div>
);

By combining static and dynamic data fetching, you can create applications that are both performant and responsive.

Handling loading and error states while fetching data in Next.js

Next.js provides a number of ways to handle loading and error states while fetching data.

One way is to use the useQuery hook. The useQuery hook provides a number of methods for handling loading and error states, including:

• isLoading: A boolean that indicates whether the query is currently loading.
• error: An error object that is returned if the query fails.
• data: The data that is returned by the query.

For example, the following code will fetch the list of blog posts from the server and display a loading indicator while the data is loading:

const [posts, setPosts, isLoading] = useQuery("posts");

return (
  <div>
    {isLoading && <div>Loading...</div>}
    {posts && <ul>{posts.map((post) => (
      <li key={post.id}>{post.title}</li>
    ))}</ul>}
  </div>
);

Another way to handle loading and error states is to use the useEffect hook. The useEffect hook can be used to run code when a component is mounted or updates, and it can be used to fetch data from the server.

For example, the following code will fetch the user’s profile data at runtime and display an error message if the request fails:

const [user, setUser] = useState(null);

useEffect(() => {
  // Fetch user data here.
  fetch("/api/user", {
    headers: {
      "Authorization": localStorage.getItem("token"),
    },
  })
    .then((response) => response.json())
    .then((data) => setUser(data))
    .catch((error) => {
      setUser(null);
      alert("Error fetching user data: " + error.message);
    });
}, []);

return (
  <div>
    {user && <h1>{user.name}</h1>}
  </div>
);

By handling loading and error states, you can create applications that are more user-friendly and reliable.

Using the SWR library to handle data fetching and caching in Next.js

SWR is a React hook library that makes it easy to fetch data from the server and cache it in the browser. It is a great way to improve the performance of your application by reducing the number of requests that are made to the server.

To use SWR in Next.js, you need to import the useSWR hook from the swr package. Then, you can use it to fetch data from the server and update the state of your component when the data is fetched.

For example, the following code will fetch the list of blog posts from the server and update the state of the posts variable:

import { useSWR } from "swr";

const [posts, setPosts] = useState([]);

const fetchPosts = () => {
  // Fetch posts from the server.
  return fetch("/api/posts").then((response) => response.json());
};

const { data, error } = useSWR("posts", fetchPosts);

setPosts(data);

return (
  <div>
    {posts && <ul>{posts.map((post) => (
      <li key={post.id}>{post.title}</li>
    ))}</ul>}
    {error && <div>Error fetching posts: {error.message}</div>}
  </div>
);

SWR is a powerful library that can be used to improve the performance of your application. It is easy to use and can be integrated with any Next.js application.

Optimizing data fetching performance in Next.js

There are a number of things you can do to optimize data fetching performance in Next.js.

• Use static site generation (SSG) for pages that are not frequently updated. SSG is a technique for generating static pages at build time. This means that the pages are generated before they are served to the user, which can improve the performance of the application.

• Use incremental static regeneration (ISR) for pages that are updated frequently. ISR is a technique for generating static pages on demand. This means that the pages are generated when they are requested, but only the parts of the page that have changed are regenerated. This can improve the performance of the application by reducing the amount of work that the server has to do.

• Use dynamic imports for components that are not used on every page. Dynamic imports allow you to import components only when they are needed. This can improve the performance of the application by reducing the amount of code that is loaded on every page.

• Use the useQuery hook to fetch data from the server at runtime. The useQuery hook provides a number of methods for handling loading and error states, including:

  • isLoading: A boolean that indicates whether the query is currently loading.
  • error: An error object that is returned if the query fails.
  • data: The data that is returned by the query.

• Use the useSWR hook to fetch data from the server and cache it in the browser. SWR is a React hook library that makes it easy to fetch data from the server and cache it in the browser. It is a great way to improve the performance of your application by reducing the number of requests that are made to the server.

• Use a CDN for static assets. A CDN is a network of servers that are distributed around the world. Using a CDN for static assets can improve the performance of your application by delivering those assets from servers that are closer to the user.

• Optimize your images. Images can be a major source of performance problems in web applications. There are a number of things you can do to optimize your images, such as:

  • Reducing the file size of your images.
  • Using lazy loading for images.
  • Using a CDN for images.

• Use a content delivery network (CDN). A CDN is a network of servers that are distributed around the world. Using a CDN for static assets, such as images and CSS files, can improve the performance of your application by delivering those assets from servers that are closer to the user.

• Minify your code. Minifying your code can reduce the file size of your application, which can improve the performance of your application.

• Combine and compress your CSS and JavaScript files. Combining and compressing your CSS and JavaScript files can reduce the number of requests that are made to the server, which can improve the performance of your application.

• Use a caching strategy. A caching strategy can help to improve the performance of your application by storing frequently accessed data in the browser’s cache. This can reduce the number of requests that are made to the server, which can improve the performance of your application.

• Use a performance monitoring tool. A performance monitoring tool can help you to identify performance bottlenecks in your application. This can help you to improve the performance of your application by fixing the bottlenecks that you identify.

By following these tips, you can improve the performance of your Next.js application and make it more responsive to users.

Using GraphQL with Next.js for efficient data fetching and caching

GraphQL is a query language and a runtime for executing queries against a data source. It is designed to be efficient and scalable, and it can be used to fetch data from a variety of sources, including databases, APIs, and file systems.

Next.js is a React framework that can be used to build server-rendered and static web applications. It provides a number of features that make it easy to use GraphQL, including:

• Automatic GraphQL server generation: Next.js can automatically generate a GraphQL server for you. This can save you a lot of time and effort, and it can help you to get started with GraphQL quickly.
• Integration with Apollo Client: Next.js integrates with Apollo Client, a popular GraphQL client library. This makes it easy to use GraphQL in your Next.js application.
• Built-in caching: Next.js provides built-in caching for GraphQL queries. This can improve the performance of your application by reducing the number of requests that are made to the server.

To use GraphQL with Next.js, you need to install the graphql and apollo-client packages. Then, you can create a GraphQL schema and define your queries.

For example, the following code defines a GraphQL schema for a simple blog application:

type Query {
  posts: [Post]
  post(id: Int!): Post
}

type Post {
  id: Int!
  title: String!
  body: String!
}

Once you have defined your GraphQL schema, you can use the useQuery hook to fetch data from the server.

For example, the following code uses the useQuery hook to fetch the list of posts from the server:

const { data, loading, error } = useQuery("posts");

if (loading) {
  return <div>Loading...</div>;
} else if (error) {
  return <div>Error fetching posts: {error.message}</div>;
} else {
  return (
    <ul>
      {data.posts.map((post) => (
        <li key={post.id}>{post.title}</li>
      ))}
    </ul>
  );
}

By using GraphQL with Next.js, you can improve the performance of your application by reducing the number of requests that are made to the server. You can also use GraphQL to fetch data from a variety of sources, including databases, APIs, and file systems.

Integrating with external data sources and APIs in Next.js

Next.js makes it easy to integrate with external data sources and APIs. There are a few different ways to do this, depending on your needs.

Using the getStaticProps and getServerSideProps hooks

The getStaticProps and getServerSideProps hooks are a great way to fetch data from external sources when your page is first loaded. This can improve the performance of your application by reducing the number of requests that are made to the server when a user visits your page.

To use the getStaticProps or getServerSideProps hooks, you need to export them from your page’s _app.js file. Then, you can use them to fetch data from the server and update the props of the page component.

For example, the following code uses the getStaticProps hook to fetch the list of blog posts from an external API:

export const getStaticProps = async () => {
  // Fetch blog posts from the API.
  const posts = await fetch("/api/posts");

  // Update the props of the page component.
  return {
    props: {
      posts,
    },
  };
};

Using the useQuery hook

The useQuery hook is a great way to fetch data from external sources at runtime. This can be useful for pages that need to be personalized for each user, such as product pages and user profiles.

To use the useQuery hook, you need to import it from the react-query package. Then, you can use it to fetch data from the server and update the state of your component when the data is fetched.

For example, the following code uses the useQuery hook to fetch the user’s profile data from an external API:

import { useQuery } from "react-query";

const [user, setUser] = useState(null);

// Fetch user data from the API.
const { data, loading, error } = useQuery("user", () => {
  return fetch("/api/user");
});

// Update the state of the component when the data is fetched.
setUser(data);

// Display an error message if the request fails.
if (error) {
  return <div>Error fetching user data: {error.message}</div>;
}

// Display the user's profile data.
return (
  <div>
    <h1>{user.name}</h1>
    <p>{user.email}</p>
  </div>
);

Using the useSWR hook

The useSWR hook is a great way to fetch data from external sources and cache it in the browser. This can improve the performance of your application by reducing the number of requests that are made to the server.

To use the useSWR hook, you need to import it from the swr package. Then, you can use it to fetch data from the server and update the state of your component when the data is fetched.

For example, the following code uses the useSWR hook to fetch the list of blog posts from an external API and cache it in the browser:

import { useSWR } from "swr";

const [posts, setPosts] = useState([]);

// Fetch blog posts from the API and cache them in the browser.
const fetchPosts = () => {
  return fetch("/api/posts").then((response) => response.json());
};

const { data, error } = useSWR("posts", fetchPosts);

// Update the state of the component when the data is fetched.
setPosts(data);

// Display an error message if the request fails.
if (error) {
  return <div>Error fetching blog posts: {error.message}</div>;
}

// Display the list of blog posts.
return (
  <ul>
    {posts.map((post) => (
      <li key={post.id}>{post.title}</li>
    ))}
  </ul>
);

By using the getStaticProps and getServerSideProps hooks, the useQuery hook, and the useSWR hook, you can easily integrate with external data sources and APIs in Next.js.

Handling data mutations with Next.js and backend APIs

Next.js makes it easy to handle data mutations with backend APIs. There are a few different ways to do this, depending on your needs.

Using the useMutation hook

The useMutation hook is a great way to make stateful mutations to your data. It is similar to the useQuery hook, but it allows you to make changes to your data, rather than just fetching it.

To use the useMutation hook, you need to import it from the react-query package. Then, you can use it to make stateful mutations to your data.

For example, the following code uses the useMutation hook to create a new blog post:

import { useMutation } from "react-query";

const [createPost, { data, loading, error }] = useMutation(async () => {
  // Make a request to the backend API to create a new blog post.
  const response = await fetch("/api/posts", {
    method: "POST",
    body: JSON.stringify({
      title: "My new blog post",
      body: "This is my new blog post.",
    }),
  });

  // Check the response status code.
  if (response.status !== 201) {
    throw new Error("Error creating blog post");
  }

  // Return the data from the response.
  return response.json();
});

// Use the `createPost` mutation to create a new blog post.
const handleSubmit = (e) => {
  e.preventDefault();

  // Create a new blog post.
  createPost({
    title: e.target.title.value,
    body: e.target.body.value,
  });
};

return (
  <form onSubmit={handleSubmit}>
    <input type="text" name="title" placeholder="Title" />
    <input type="text" name="body" placeholder="Body" />
    <button type="submit">Create</button>
  </form>
);

Using the useSWR hook

The useSWR hook is a great way to make stateful mutations to your data and cache them in the browser. This can improve the performance of your application by reducing the number of requests that are made to the server.

To use the useSWR hook, you need to import it from the swr package. Then, you can use it to make stateful mutations to your data and cache them in the browser.

For example, the following code uses the useSWR hook to create a new blog post and cache it in the browser:

import { useSWR } from "swr";

const [createPost, { data, loading, error }] = useSWR(
  "/api/posts",
  async () => {
    // Make a request to the backend API to create a new blog post.
    const response = await fetch("/api/posts", {
      method: "POST",
      body: JSON.stringify({
        title: "My new blog post",
        body: "This is my new blog post.",
      }),
    });

    // Check the response status code.
    if (response.status !== 201) {
      throw new Error("Error creating blog post");
    }

    // Return the data from the response.
    return response.json();
  }
);

// Use the `createPost` mutation to create a new blog post.
const handleSubmit = (e) => {
  e.preventDefault();

  // Create a new blog post.
  createPost({
    title: e.target.title.value,
    body: e.target.body.value,
  });
};

return (
  <form onSubmit={handleSubmit}>
    <input type="text" name="title" placeholder="Title" />
    <input type="text" name="body" placeholder="Body" />
    <button type="submit">Create</button>
  </form>
);

By using the useMutation hook and the useSWR hook, you can easily handle data mutations with backend APIs in Next.js.

Implementing pagination and infinite scrolling in Next.js with server-side rendering

Here are the steps on how to implement pagination and infinite scrolling in Next.js with server-side rendering:

1. Create a pagination component. This component will be responsible for displaying the pagination links.
2. Create a function that fetches the next page of data. This function will be called when the user clicks on a pagination link.
3. Use the getStaticProps hook to fetch the initial data. The getStaticProps hook is a Next.js hook that is used to fetch data at build time.
4. Use the useEffect hook to fetch the next page of data when the user scrolls to the bottom of the page. The useEffect hook is a React hook that is used to run code when a component is mounted or updates.
5. Use the useQuery hook to fetch the data for the current page. The useQuery hook is a React hook that is used to fetch data from the server.
6. Use the useRef hook to store the current page number. The useRef hook is a React hook that is used to store a reference to a variable.
7. Use the useState hook to store the state of the pagination component. The useState hook is a React hook that is used to store the state of a component.
8. Render the pagination component. The pagination component will be responsible for displaying the pagination links.
9. Fetch the next page of data when the user clicks on a pagination link. The function that fetches the next page of data will be called when the user clicks on a pagination link.
10. Use the useQuery hook to fetch the data for the current page. The useQuery hook will be used to fetch the data for the current page.
11. Use the useRef hook to store the current page number. The useRef hook will be used to store the current page number.
12. Use the useState hook to store the state of the pagination component. The useState hook will be used to store the state of the pagination component.
13. Render the pagination component. The pagination component will be responsible for displaying the pagination links.

Here is an example of how to implement pagination and infinite scrolling in Next.js with server-side rendering:

import React, { useEffect, useRef, useState } from "react";
import { getStaticProps } from "next";
import Pagination from "./Pagination";

const Posts = ({ posts }) => {
  const [currentPage, setCurrentPage] = useState(1);
  const [totalPages, setTotalPages] = useState(1);

  useEffect(() => {
    setTotalPages(Math.ceil(posts.length / 10));
  }, [posts]);

  return (
    <div>
      <ul>
        {posts.slice((currentPage - 1) * 10, currentPage * 10).map((post, i) => (
          <li key={i}>{post.title}</li>
        ))}
      </ul>
      <Pagination
        currentPage={currentPage}
        totalPages={totalPages}
        setCurrentPage={setCurrentPage}
      />
    </div>
  );
};

export const getStaticProps = async () => {
  const posts = await fetch("/api/posts").then((response) => response.json());

  return {
    props: {
      posts,
    },
  };
};

export default Posts;

This code will fetch the first 10 posts from the API and display them on the page. When the user scrolls to the bottom of the page, the next 10 posts will be fetched from the API. The user can click on the pagination links to navigate to different pages.

Using serverless functions in Next.js for server-side data processing and integration with third-party APIs

Serverless functions in Next.js are a great way to process data on the server and integrate with third-party APIs. They are lightweight and scalable, and they can be used to perform a variety of tasks, such as:

• Processing and transforming data
• Calling third-party APIs
• Sending emails
• Creating and updating records in a database
• Sending push notifications

To use serverless functions in Next.js, you need to create a file in the pages/api directory. The file name should be the same as the function name, and it should have the .js extension. For example, to create a function called helloWorld, you would create a file called helloWorld.js in the pages/api directory.

The code in the serverless function can be written in any language that is supported by Node.js. For example, you could use JavaScript, TypeScript, or Python.

Once you have created the serverless function, you can call it from your React components using the useSWR hook. The useSWR hook is a React hook that is used to fetch data from the server and cache it in the browser.

For example, the following code uses the useSWR hook to call the helloWorld serverless function and display the result in the browser:

import React, { useSWR } from "react";

const HelloWorld = () => {
  const { data, error } = useSWR("/api/helloWorld");

  if (error) {
    return <div>Error calling serverless function: {error.message}</div>;
  } else {
    return <div>Hello, {data.name}</div>;
  }
};

export default HelloWorld;

This code will call the helloWorld serverless function and display the result in the browser. If the serverless function fails, an error message will be displayed.

Serverless functions in Next.js are a powerful tool that can be used to process data on the server and integrate with third-party APIs. They are lightweight and scalable, and they can be used to perform a variety of tasks.

Building real-time applications with Next.js and WebSockets

Next.js and WebSockets can be used to build real-time applications. WebSockets are a type of persistent connection that allows for two-way communication between the server and the client. This makes them ideal for applications that need to update the user interface in real time, such as chat applications, stock tickers, and live video streaming.

To use WebSockets in Next.js, you need to import the ws package from next/websocket. Then, you can create a WebSocket connection using the createSocket() function. The createSocket() function takes two arguments: the URL of the WebSocket server and a callback function. The callback function will be called when the connection is opened, closed, or an error occurs.

For example, the following code creates a WebSocket connection to a chat server:

import { createSocket } from "next/websocket";

const Chat = () => {
  const [socket, setSocket] = useState();

  useEffect(() => {
    const url = "ws://localhost:8080/chat";
    setSocket(createSocket(url, () => {
      console.log("Socket opened");
    }, () => {
      console.log("Socket closed");
    }, (error) => {
      console.log("Socket error:", error);
    }));
  }, []);

  return (
    <div>
      <input
        type="text"
        placeholder="Enter message"
        onChange={(e) => {
          socket.send(e.target.value);
        }}
      />
    </div>
  );
};

export default Chat;

This code will create a WebSocket connection to a chat server. When the user enters a message and presses Enter, the message will be sent to the server. The server will then broadcast the message to all connected clients.

Next.js and WebSockets can be used to build a variety of real-time applications. By using WebSockets, you can keep your users updated in real time with the latest information.

Securing data fetching in Next.js with authentication and authorization techniques

Next.js provides a number of features that can be used to secure data fetching.

Authentication

Authentication is the process of verifying the identity of a user. Next.js supports a variety of authentication methods, including:

• Basic authentication: Basic authentication is a simple and secure way to authenticate users. It uses a username and password to verify the identity of the user.
• OAuth 2.0: OAuth 2.0 is a popular authorization framework that allows users to grant access to their data to third-party applications without having to share their passwords.
• JWT: JWT (JSON Web Tokens) are a secure way to transmit information between a server and a client. They can be used to store user information, such as username, password, and role.

Authorization

Authorization is the process of determining what a user is allowed to do. Next.js supports a variety of authorization methods, including:

• Role-based access control (RBAC): RBAC is a popular authorization model that allows you to define permissions for users based on their role.
• Access control lists (ACLs): ACLs are a simple way to define permissions for users based on the resources they are trying to access.

Data security

Next.js also provides a number of features that can be used to secure data at rest and in transit.

Data at rest

Data at rest is data that is stored on a server. Next.js supports a variety of methods for securing data at rest, including:

• Encryption: Encryption is the process of converting data into an unreadable format. This can help to protect data from unauthorized access.
• Access control: Access control can be used to restrict who has access to data at rest.

Data in transit

Data in transit is data that is being transmitted between a server and a client. Next.js supports a variety of methods for securing data in transit, including:

• HTTPS: HTTPS is a secure protocol that encrypts data in transit.
• Firewalls: Firewalls can be used to block unauthorized access to data in transit.
• IDS/IPS: IDS/IPS (intrusion detection systems/intrusion prevention systems) can be used to detect and prevent attacks on data in transit.

By using the features provided by Next.js, you can secure your data fetching and protect your users’ data.

Using Next.js with state management libraries like Redux and MobX.

Next.js is a great framework for building React applications. It provides a number of features that can make development easier and faster. However, Next.js does not provide any state management out of the box. This is where state management libraries like Redux and MobX come in.

State management libraries provide a way to manage the state of your application. This can be helpful for applications with a lot of state, or for applications that need to share state between components.

There are a number of state management libraries available, but Redux and MobX are two of the most popular. Redux is a global state management library, while MobX is a local state management library.

Redux

Redux is a global state management library. This means that there is only one store in your application, and all of the state is stored in that store. Redux is a popular choice for applications with a lot of state, or for applications that need to share state between components.

To use Redux in your Next.js application, you need to install the Redux package and create a store. The store is the object that holds the state of your application.

Once you have created a store, you can use it to manage the state of your application. To do this, you need to use the dispatch() method to dispatch actions to the store. Actions are objects that describe changes to the state of your application.

For example, the following code dispatches an action to the store to change the value of a state variable:

import { createStore } from "redux";

const store = createStore(reducer);

const action = {
  type: "INCREMENT",
};

store.dispatch(action);

The reducer function is a function that takes the current state and an action as arguments and returns the new state.

MobX

MobX is a local state management library. This means that each component can have its own store. MobX is a popular choice for applications with a small amount of state, or for applications that do not need to share state between components.

To use MobX in your Next.js application, you need to install the MobX package and import the observable and observer functions.

The observable function is used to create an observable variable. Observable variables are variables that can be observed by other components.

The observer function is used to create an observer component. Observer components can observe observable variables and update their state when the observable variable changes.

For example, the following code creates an observable variable and an observer component:

import { observable } from "mobx";
import { observer } from "mobx-react";

const counter = observable({
  value: 0,
});

const Counter = observer(() => {
  return (
    <div>
      The counter is {counter.value}.
    </div>
  );
});

export default Counter;

The counter variable is an observable variable that stores the value of the counter. The Counter component is an observer component that observes the counter variable and updates its state when the counter variable changes.

By using state management libraries like Redux and MobX, you can manage the state of your application more easily and efficiently. This can help to improve the performance of your application and make it easier to develop and maintain.

Chapter 4: Styling in Next.js

CSS modules in Next.js

CSS modules are a way to scope CSS to specific components. This can help to avoid CSS conflicts and make your code more maintainable.

To use CSS modules in Next.js, you need to add the css-modules package to your project. Then, you can use the ` property to import CSS modules into your components.

For example, the following code imports a CSS module into a component:

import React from "react";
import css from "css-modules";

const MyComponent = () => {
  return (
    <div css={css(".my-component", {
      color: "red",
    })}>
      This is my component.
    </div>
  );
};

export default MyComponent;

The ` function takes two arguments: the name of the CSS module and an object of CSS properties. The CSS properties will be applied to the component.

CSS modules are a great way to scope CSS to specific components. This can help to avoid CSS conflicts and make your code more maintainable.

Here are some benefits of using CSS modules:

• Scoped CSS: CSS modules scope CSS to specific components, which helps to avoid CSS conflicts.
• Maintainable code: CSS modules make code more maintainable by making it easier to find and edit CSS styles.
• Smaller bundle sizes: CSS modules can help to reduce the size of your bundle by only including the CSS that is used by each component.

If you are using Next.js, I recommend using CSS modules to scope your CSS. It is a great way to improve the maintainability and performance of your code.

Using third-party CSS libraries in Next.js

Next.js makes it easy to use third-party CSS libraries. To use a third-party CSS library, you need to install the library and import it into your project.

For example, to use Bootstrap, you would need to install the Bootstrap package and import it into your project.

npm install bootstrap

import 'bootstrap/dist/css/bootstrap.min.css';

Once you have installed and imported the library, you can use it in your code. For example, to use the Bootstrap card component, you would use the following code:

<div class="card">
  <div class="card-body">
    This is a card.
  </div>
</div>

Next.js will automatically compile the CSS for the library and include it in your bundle. This means that you don’t need to worry about loading the CSS yourself.

Here are some popular third-party CSS libraries that you can use with Next.js:

• Bootstrap
• Material UI
• Tailwind CSS
• Bulma
• Foundation

If you are using a third-party CSS library, I recommend reading the library’s documentation to learn how to use it.

Global CSS in Next.js

Global CSS is CSS that is applied to all pages in your Next.js application. It is typically used to style the layout of your application, such as the header, footer, and navigation bar.

To add global CSS to your Next.js application, you can create a file called `styles. in the root directory of your project. Then, you can add your CSS to the file.

For example, the following code adds a global CSS rule to change the font color of the body element:

body {
  color: red;
}

Once you have added your CSS to the styles. file, you need to import it into your application. To do this, you can add the following code to the pages/_app.js` file:

import './styles.css';

This will import the `styles. file into your application and apply the CSS to all pages.

Note: Global CSS can be used to style the layout of your application, but it is not recommended for styling individual components. For styling individual components, you should use CSS modules.

Styling with Sass and LESS

Sass and LESS are both CSS preprocessors. They allow you to write more powerful and maintainable CSS code.

Sass is a superset of CSS, which means that any valid CSS is also valid Sass. Sass adds features such as variables, mixins, and functions, which can make your CSS code more concise and reusable.

LESS is another CSS preprocessor that is similar to Sass. LESS also adds features such as variables, mixins, and functions, but it has a different syntax than Sass.

To use Sass or LESS with Next.js, you need to install the corresponding package. For Sass, you would install the sass package. For LESS, you would install the ` package.

Once you have installed the package, you can start using Sass or LESS in your Next.js application. To do this, you need to add the . or . extension to your CSS files.

For example, the following code is a Sass file:

.my-component {
  color: $color;
}

$color: red;

This code defines a variable called $color and sets it to the value red. It then defines a rule for the .my-component selector and sets the color to $color.

When you compile your Sass or LESS files, Next.js will convert them to CSS. This means that you can use Sass or LESS in your Next.js application without having to worry about the underlying CSS.

Here are some benefits of using Sass or LESS:

• More powerful CSS: Sass and LESS add features such as variables, mixins, and functions, which can make your CSS code more powerful and maintainable.
• More maintainable CSS: Sass and LESS can help you to write more maintainable CSS code by making it easier to organize and reuse your CSS code.
• Better performance: Sass and LESS can improve the performance of your application by compiling your CSS code into a single file.

If you are looking for a way to improve the power, maintainability, and performance of your CSS code, I recommend using Sass or LESS.

Using Tailwind CSS in Next.js

Tailwind CSS is a utility-first CSS framework that provides a set of classes that can be used to style your components. It is a great way to keep your CSS code DRY (don’t repeat yourself) and to make it easier to write responsive code.

To use Tailwind CSS in Next.js, you need to install the Tailwind CSS package and add the tailwind.config.js file to your project.

npm install tailwindcss

touch tailwind.config.js

The tailwind.config.js file is where you can configure Tailwind CSS. For example, you can set the default font family, colors, and spacing.

Once you have installed Tailwind CSS and configured it, you can start using it in your Next.js application. To do this, you need to import the Tailwind CSS classes into your components.

For example, the following code imports the Tailwind CSS text-center class into a component:

import { textCenter } from "tailwindcss";

const MyComponent = () => {
  return (
    <div className={textCenter}>
      This is my component.
    </div>
  );
};

export default MyComponent;

The textCenter class will center the text inside the div element.

Here are some benefits of using Tailwind CSS:

• DRY CSS: Tailwind CSS provides a set of classes that can be used to style your components. This can help you to keep your CSS code DRY (don’t repeat yourself).
• Responsive CSS: Tailwind CSS provides classes that can be used to make your code responsive. This can help you to make sure that your website looks good on all devices.
• Concise CSS: Tailwind CSS classes are concise and easy to read. This can help you to write more maintainable CSS code.

If you are looking for a way to improve the DRYness, responsiveness, and conciseness of your CSS code, I recommend using Tailwind CSS.

Theming and styling with CSS variables in Next.js

CSS variables are a great way to keep your CSS code DRY (don’t repeat yourself). They can also be used to create themes for your application.

To use CSS variables in Next.js, you need to define them in your CSS file. For example, the following code defines a CSS variable called color:

:root {
  --color: red;
}

You can then use the CSS variable in your CSS code. For example, the following code sets the color of the h1 element to the value of the color variable:

h1 {
  color: var(--color);
}

CSS variables can also be used to create themes for your application. For example, you could create a light theme and a dark theme. You could then use the CSS variables to set the colors for each theme.

To create a theme, you need to define the CSS variables for the theme in a separate CSS file. For example, the following code defines the CSS variables for a light theme:

:root {
  --color-primary: #fff;
  --color-secondary: #000;
}

You can then import the theme CSS file into your application. To do this, you can add the following code to your pages/_app.js file:

import "theme/light.css";

Once you have imported the theme CSS file, you can use the CSS variables in your CSS code. For example, the following code sets the color of the h1 element to the value of the color-primary variable:

h1 {
  color: var(--color-primary);
}

CSS variables are a great way to keep your CSS code DRY and to create themes for your application.

Dynamic styling with styled-components in Next.js

Dynamic styling with styled-components in Next.js is a great way to add interactivity to your website. It allows you to change the style of your components based on user input or other data.

To use dynamic styling with styled-components, you need to use the ` prop to pass in a function that returns the CSS for the component. The function can access the props of the component and the state of the application.

For example, the following code uses dynamic styling to change the color of a button based on the value of the isDisabled prop:

const Button = styled.button`
  color: ${(props) => (props.isDisabled ? "red" : "blue")};
`;

const MyComponent = () => {
  return (
    <Button isDisabled={true}>
      Click me!
    </Button>
  );
};

export default MyComponent;

In this example, the Button component uses the prop to pass in a function that returns the CSS for the component. The function accesses theisDisabled` prop of the component and returns the color red if the prop is true, or blue if the prop is false.

Dynamic styling with styled-components is a powerful way to add interactivity to your website. It allows you to change the style of your components based on user input or other data.

Creating responsive layouts in Next.js with CSS Grid and Flexbox

CSS Grid and Flexbox are two powerful CSS layout systems that can be used to create responsive layouts in Next.js.

CSS Grid is a two-dimensional layout system that allows you to create complex layouts with rows and columns. Flexbox is a one-dimensional layout system that allows you to align and distribute elements on a line.

To use CSS Grid in Next.js, you need to add the grid property to the element that you want to use as the grid container. For example, the following code creates a grid container with two rows and three columns:

<div class="grid">
  <div class="row">
    <div class="column"></div>
    <div class="column"></div>
    <div class="column"></div>
  </div>
  <div class="row">
    <div class="column"></div>
    <div class="column"></div>
    <div class="column"></div>
  </div>
</div>

The grid property can also be used to specify the size and alignment of the grid cells. For example, the following code specifies that the grid cells should be 100px wide and that they should be aligned to the center of the grid container:

<div class="grid">
  <div class="row">
    <div class="column" style="width: 100px; align-self: center;">
      This is a grid cell.
    </div>
    <div class="column" style="width: 100px; align-self: center;">
      This is another grid cell.
    </div>
    <div class="column" style="width: 100px; align-self: center;">
      This is a third grid cell.
    </div>
  </div>
  <div class="row">
    <div class="column" style="width: 100px; align-self: center;">
      This is a fourth grid cell.
    </div>
    <div class="column" style="width: 100px; align-self: center;">
      This is a fifth grid cell.
    </div>
    <div class="column" style="width: 100px; align-self: center;">
      This is a sixth grid cell.
    </div>
  </div>
</div>

To use Flexbox in Next.js, you need to add the flex property to the element that you want to use as the flex container. For example, the following code creates a flex container with two flex items:

<div class="flex">
  <div class="flex-item"></div>
  <div class="flex-item"></div>
</div>

The flex property can also be used to specify the direction of the flex container, the alignment of the flex items, and the flex properties of the flex items. For example, the following code specifies that the flex container should be in the row direction, that the flex items should be aligned to the center of the flex container, and that the flex items should be of equal size:

<div class="flex flex-direction-row">
  <div class="flex-item" style="flex: 1 0 0;">
    This is a flex item.
  </div>
  <div class="flex-item" style="flex: 1 0 0;">
    This is another flex item.
  </div>
</div>

CSS Grid and Flexbox are powerful tools that can be used to create responsive layouts in Next.js. They allow you to create complex layouts with ease and to make sure that your website looks good on all devices.

Using media queries and breakpoints in Next.js for responsive design

Media queries are a powerful way to control the appearance of your website on different devices. They allow you to specify different CSS rules for different screen sizes, orientations, and other factors.

Breakpoints are points at which your website will switch between different media queries. For example, you might have a breakpoint at 768px, which is the width of a typical laptop screen. At this breakpoint, you might want to change the layout of your website so that it is more suited to a larger screen.

To use media queries and breakpoints in Next.js, you need to add the media attribute to your CSS rules. The media attribute takes a media query as its value. For example, the following code specifies that the following CSS rule should be applied to screens that are at least 768px wide:

@media (min-width: 768px) {
  .my-class {
    width: 100%;
  }
}

You can also use media queries to target specific devices, such as phones, tablets, and desktops. For example, the following code specifies that the following CSS rule should be applied to phones:

@media (max-width: 767px) {
  .my-class {
    display: block;
  }
}

Media queries and breakpoints are a powerful way to create responsive websites. They allow you to make sure that your website looks good on all devices, regardless of their size or orientation.

Server-side rendering of CSS in Next.js

Server-side rendering (SSR) is a technique for rendering web pages on the server before they are sent to the client. This has several benefits, including:

• Improved SEO: Search engines can index pages that are rendered on the server.
• Faster loading times: Pages that are rendered on the server are loaded faster than pages that are rendered on the client.
• Improved security: Pages that are rendered on the server are less vulnerable to attacks.

Next.js supports SSR out of the box. To use SSR, you need to add the getServerSideProps() function to your pages. The getServerSideProps() function is called by the server before the page is rendered. It can be used to fetch data from the server and to generate the HTML for the page.

For example, the following code shows how to use SSR to render a page with a list of products:

export default function Home() {
  const products = await getServerSideProps();
  return (
    <div>
      <h1>Home</h1>
      <ul>
        {products.map((product) => (
          <li key={product.id}>{product.name}</li>
        ))}
      </ul>
    </div>
  );
}

async function getServerSideProps() {
  const products = await fetch("/api/products");
  const productsData = await products.json();
  return {
    props: {
      products: productsData,
    },
  };
}

In this example, the getServerSideProps() function fetches the list of products from the /api/products endpoint. It then returns the list of products as props to the Home component.

When the page is rendered, the server will first fetch the list of products from the database. It will then render the page with the list of products. This ensures that the page is always up-to-date, even if the products in the database change.

Server-side rendering is a powerful technique that can be used to improve the performance, SEO, and security of your website. If you are using Next.js, you should consider using SSR for your pages.

Performance optimization for CSS in Next.js

There are a number of things you can do to optimize the performance of CSS in Next.js. Here are a few tips:

• Use CSS modules. CSS modules are a great way to keep your CSS code DRY and to improve performance. They allow you to scope your CSS to specific components, which can help to reduce the size of the CSS bundle.
• Use minification. Minification is the process of removing unnecessary characters from CSS code. This can help to reduce the size of the CSS bundle and improve performance.
• Use caching. Caching is the process of storing CSS code in memory so that it does not need to be downloaded from the server each time the page is loaded. This can help to improve performance by reducing the number of requests that are made to the server.
• Use lazy loading. Lazy loading is the process of loading CSS code only when it is needed. This can help to improve performance by reducing the amount of CSS code that is loaded on each page load.
• Use critical path CSS. Critical path CSS is the CSS code that is essential for the layout and appearance of your website. It is a good idea to minify and cache critical path CSS to improve performance.
• Use a CDN. A CDN (content delivery network) is a network of servers that are distributed around the world. Using a CDN can help to improve the performance of your website by delivering CSS code from a server that is close to the user.

By following these tips, you can improve the performance of CSS in Next.js and make your website load faster.

Styling specific components in Next.js with CSS-in-JS techniques

CSS-in-JS is a technique for writing CSS code inside JavaScript code. This can be useful for styling specific components in your Next.js application.

There are a number of CSS-in-JS libraries available, such as styled-components, Emotion, and Stitches. Each library has its own strengths and weaknesses, so it’s important to choose the library that’s right for your project.

Once you’ve chosen a CSS-in-JS library, you can start styling your components. For example, the following code shows how to use styled-components to style a button component:

import styled from "styled-components";

const Button = styled.button`
  color: red;
  background-color: blue;
  padding: 10px;
  cursor: pointer;
`;

export default function Home() {
  return (
    <div>
      <Button>Click me!</Button>
    </div>
  );
}

In this example, the Button component is styled using styled-components. The color, background-color, padding, and cursor properties are all set to specific values.

When the Home component is rendered, the Button component will be styled according to the properties that have been set. This allows you to style specific components in your Next.js application without having to write any CSS code.

CSS-in-JS is a powerful technique that can be used to improve the maintainability and performance of your Next.js application. If you’re not already using CSS-in-JS, I encourage you to give it a try.

Creating animations and transitions in Next.js with CSS and JavaScript

There are a number of ways to create animations and transitions in Next.js. Here are a few examples:

Using CSS transitions

CSS transitions allow you to animate the changes in CSS properties over time. For example, the following code shows how to animate the opacity of an element from 0 to 1 over 1 second:

.my-element {
  opacity: 0;
  transition: opacity 1s;
}

.my-element.active {
  opacity: 1;
}

When the element is clicked, it will be animated from being invisible to being visible.

Using CSS animations

CSS animations allow you to create more complex animations than transitions. For example, the following code shows how to create a bouncing animation for an element:

.my-element {
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%, 20%, 60%, 80%, 100% {
    transform: translateY(0);
  }
  20% {
    transform: translateY(-20px);
  }
  40% {
    transform: translateY(10px);
  }
  60% {
    transform: translateY(-10px);
  }
}

When the element is clicked, it will start bouncing up and down.

Using JavaScript animations

JavaScript animations allow you to create even more complex animations than CSS animations. For example, the following code shows how to create a spinning animation for an element:

import React, { useState } from "react";

const SpinningElement = () => {
  const [isSpinning, setIsSpinning] = useState(false);

  const handleClick = () => {
    setIsSpinning(!isSpinning);
  };

  return (
    <div
      onClick={handleClick}
      style={{
        animation: isSpinning ? "spin 1s linear infinite" : "",
      }}
    >
      <h1>Spinning!</h1>
    </div>
  );
};

export default SpinningElement;

When the element is clicked, it will start spinning.

These are just a few examples of how to create animations and transitions in Next.js. There are many other ways to do it, so experiment and find what works best for you.

Using Next.js with design systems like Material UI and Ant Design

Next.js is a great framework for building web applications, and design systems can help you to create consistent and high-quality user interfaces. Here are a few things to keep in mind when using Next.js with design systems:

• Choose the right design system. There are many different design systems available, so it’s important to choose one that’s right for your project. Consider the size and complexity of your project, as well as the specific features that you need.
• Import the design system into your Next.js project. Once you’ve chosen a design system, you need to import it into your Next.js project. This can be done using a package manager like npm or yarn.
• Use the design system components in your Next.js code. Once the design system is imported, you can start using its components in your Next.js code. The components will be styled according to the design system’s guidelines, so you don’t need to worry about styling them yourself.
• Customize the design system to meet your needs. Most design systems are highly customizable, so you can tweak them to meet your specific needs. This might involve changing the colors, fonts, or other aspects of the design system.

By following these tips, you can use Next.js with design systems to create consistent and high-quality user interfaces.

Here are some examples of design systems that can be used with Next.js:

• Material UI is a popular design system that is based on Google’s Material Design guidelines.
• Ant Design is another popular design system that is based on Alibaba’s design language.
• Bootstrap is a more traditional design system that is based on HTML and CSS.

Each design system has its own strengths and weaknesses, so it’s important to choose the one that’s right for your project.

Using custom fonts and icons in Next.js

Next.js makes it easy to use custom fonts and icons in your application. Here are a few ways to do it:

Using Google Fonts

Google Fonts is a great way to add custom fonts to your website. To use Google Fonts in Next.js, you can use the @import rule in your CSS file. For example, the following code imports the Roboto font:

@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500;700&display=swap');

Once the font is imported, you can use it in your CSS code. For example, the following code sets the font family of the h1 element to Roboto:

h1 {
  font-family: Roboto;
}

Using Font Awesome

Font Awesome is a great way to add custom icons to your website. To use Font Awesome in Next.js, you can use the <i> tag. For example, the following code adds the “home” icon to the h1 element:

<h1><i class="fas fa-home"></i> My Website</h1>

The fas class refers to the Font Awesome Solid icon set. There are also other icon sets available, such as far (Font Awesome Regular) and fab (Font Awesome Brands).

Using Custom Fonts and Icons

If you want to use custom fonts and icons that are not hosted by Google Fonts or Font Awesome, you can host them yourself and import them into your Next.js application. To do this, you need to first host the fonts and icons on a web server. Once they are hosted, you can import them into your Next.js application using the @import rule in your CSS file. For example, the following code imports a custom font that is hosted on my website:

@import url('https://example.com/fonts/my-font.css');

Once the font is imported, you can use it in your CSS code. For example, the following code sets the font family of the h1 element to my custom font:

h1 {
  font-family: my-font;
}

The same process can be used to import custom icons.

Image optimization and lazy loading in Next.js with CSS

Here are some tips on how to optimize images and lazy load them in Next.js with CSS:

• Use the right image format. Not all image formats are created equal. Some formats, such as JPEG and PNG, are better suited for photographs, while others, such as GIF and SVG, are better suited for graphics. Choose the right image format for your content to optimize file size.
• Reduce the image size. You can reduce the size of an image by using a tool like ImageOptim or TinyPNG. These tools will compress the image without sacrificing quality.
• Lazy load images. Lazy loading is a technique that defers the loading of images until they are visible on the screen. This can help to improve the loading performance of your website. Next.js makes it easy to lazy load images using the next/image component.
• Use a CDN. A CDN (content delivery network) is a network of servers that are distributed around the world. Using a CDN can help to improve the performance of your website by delivering images from a server that is close to the user.

By following these tips, you can optimize images and lazy load them in Next.js with CSS to improve the performance of your website.

Styling forms in Next.js with CSS and form libraries like Formik and react-hook-form

Here are some tips on how to style forms in Next.js with CSS and form libraries like Formik and react-hook-form:

• Use CSS classes to style your forms. This will make it easier to maintain your code and to make changes to your forms in the future.
• Use a consistent naming convention for your CSS classes. This will make it easier to find and understand the CSS code that styles your forms.
• Use a form library like Formik or react-hook-form to handle the state and validation of your forms. This will free you up to focus on styling your forms.
• Use a CSS framework like Bootstrap or Material UI to style your forms. This will give you a head start on styling your forms and will help you to create consistent and high-quality forms.

By following these tips, you can style forms in Next.js with CSS and form libraries like Formik and react-hook-form to create forms that are both stylish and functional.

Here are some additional tips:

• Use labels for all of your form fields. This will help users to understand what information is being requested.
• Use placeholder text for all of your form fields. This will give users an idea of what kind of information is expected.
• Use error messages to indicate any errors in a user’s form submission. This will help users to correct any errors and to submit their form successfully.
• Use a clear and concise layout for your forms. This will make it easy for users to find and enter the information that is being requested.
• Use a consistent design for all of your forms. This will help users to learn how to use your forms and to find the information that they need.

By following these tips, you can create forms that are both user-friendly and stylish.

Debugging and troubleshooting CSS issues in Next.js

Here are some tips on how to debug and troubleshoot CSS issues in Next.js:

• Use the Chrome DevTools. The Chrome DevTools are a powerful tool that can be used to debug CSS issues. To use the Chrome DevTools, open the Chrome browser and navigate to the page that you are having trouble with. Then, open the Chrome DevTools by pressing Ctrl+Shift+I (on Windows and Linux) or Cmd+Option+I (on macOS). Once the Chrome DevTools are open, you can use the Elements panel to inspect the HTML and CSS of the page. You can also use the Sources panel to view the JavaScript code that is running on the page.
• Use the console. The console is a powerful tool that can be used to debug CSS issues. To use the console, open the Chrome DevTools and click on the Console tab. Then, type in a CSS selector and press Enter. The console will display the CSS rules that apply to the selected element. You can also use the console to run JavaScript code.
• Use the Network panel. The Network panel can be used to debug CSS issues that are caused by slow loading of CSS files. To use the Network panel, open the Chrome DevTools and click on the Network tab. Then, refresh the page. The Network panel will display a list of all of the resources that were loaded when the page was refreshed. You can use the Network panel to identify any CSS files that are taking a long time to load.
• Use the Performance panel. The Performance panel can be used to debug CSS issues that are causing performance problems. To use the Performance panel, open the Chrome DevTools and click on the Performance tab. Then, start recording a performance trace by clicking on the Record button. Once you have recorded a performance trace, you can use the Performance panel to identify any CSS rules that are causing performance problems.

By following these tips, you can debug and troubleshoot CSS issues in Next.js.

Optimizing CSS performance in Next.js with code splitting and critical CSS techniques.

Here are some tips on how to optimize CSS performance in Next.js with code splitting and critical CSS techniques:

• Use code splitting. Code splitting is a technique that allows you to split your CSS code into smaller chunks. This can help to improve the loading performance of your website by reducing the amount of CSS code that needs to be loaded upfront. Next.js makes it easy to use code splitting with the next/dynamic component.
• Use critical CSS. Critical CSS is a technique that allows you to load only the CSS that is essential for the initial rendering of your website. This can help to improve the loading performance of your website by reducing the amount of CSS code that needs to be loaded upfront. Next.js makes it easy to use critical CSS with the next/critical component.
• Minify your CSS. Minifying your CSS can help to reduce the size of your CSS files, which can improve the loading performance of your website.
• Combine your CSS files. Combining your CSS files can help to reduce the number of HTTP requests that are made, which can improve the loading performance of your website.
• Use a CDN. A CDN (content delivery network) is a network of servers that are distributed around the world. Using a CDN can help to improve the performance of your website by delivering CSS files from a server that is close to the user.

By following these tips, you can optimize CSS performance in Next.js with code splitting and critical CSS techniques to improve the performance of your website.

Chapter 5: API Routes in Next.js

What are API routes?

API routes are a feature of Next.js that allow you to create server-side APIs. They are located in the pages/api directory and are mapped to the /api route. API routes can be used to serve data to other applications, such as mobile apps or other web applications.

To create an API route, you need to create a file in the pages/api directory. The file name must match the route that you want to create. For example, to create a route for /api/users, you would create a file called users.js.

The code in the API route file is executed on the server. This means that the data is not sent to the client until it has been processed by the server. This can improve performance and security.

API routes can be used to serve any type of data. For example, you could use them to serve JSON, XML, or even HTML.

Here is an example of an API route that serves JSON data:

export default function (req, res) {
  const users = [
    {
      name: "John Doe",
      email: "johndoe@example.com"
    },
    {
      name: "Jane Doe",
      email: "janedoe@example.com"
    }
  ];

  res.json(users);
}

This route will return a JSON object with two users.

API routes are a powerful feature of Next.js that can be used to create server-side APIs. They are easy to use and can be used to serve any type of data.

Creating API routes in Next.js

Here are the steps on how to create API routes in Next.js:

1. Create a new Next.js project using the create-next-app command.
2. Create a new file in the pages/api directory. The file name must match the route that you want to create. For example, to create a route for /api/users, you would create a file called users.js.
3. In the API route file, export a function that takes two parameters: req and res.
4. The req parameter is an object that contains information about the request, such as the method, the headers, and the body.
5. The res parameter is an object that allows you to send a response to the request.
6. To send a response, use the res.json() method to send JSON data, the res.send() method to send a string, or the res.redirect() method to redirect the request to a new URL.
7. Once you have finished writing the API route, start the development server using the npm run dev command.
8. You can now test the API route by making a request to the URL. For example, to test the route for /api/users, you would make a request to http://localhost:3000/api/users.

Here is an example of an API route that serves JSON data:

export default function (req, res) {
  const users = [
    {
      name: "John Doe",
      email: "johndoe@example.com"
    },
    {
      name: "Jane Doe",
      email: "janedoe@example.com"
    }
  ];

  res.json(users);
}

This route will return a JSON object with two users.

API routes are a powerful feature of Next.js that can be used to create server-side APIs. They are easy to use and can be used to serve any type of data.

Handling HTTP requests in Next.js

Next.js makes it easy to handle HTTP requests. You can use the next/fetch or fetch functions to make requests to any HTTP endpoint.

The next/fetch function is a wrapper around the fetch function that provides some additional features, such as automatic caching and error handling.

To use the next/fetch function, you need to import it from the next package. Then, you can use it to make requests to any HTTP endpoint.

For example, the following code makes a request to the /api/users endpoint and displays the results in the browser:

import { fetch } from "next";

export default function Home() {
  const { data } = await fetch("/api/users");

  return (
    <div>
      <h1>Users</h1>
      {data.map((user) => (
        <p key={user.id}>{user.name}</p>
      ))}
    </div>
  );
}

The fetch function is a standard JavaScript function that can be used to make requests to any HTTP endpoint.

To use the fetch function, you need to import it from the fetch package. Then, you can use it to make requests to any HTTP endpoint.

For example, the following code makes a request to the /api/users endpoint and displays the results in the browser:

import fetch from "fetch";

export default function Home() {
  const response = await fetch("/api/users");
  const data = await response.json();

  return (
    <div>
      <h1>Users</h1>
      {data.map((user) => (
        <p key={user.id}>{user.name}</p>
      ))}
    </div>
  );
}