Implementing CSS injection on a Next.js page during server-side rendering - tips and tricks!

Question

Implementing CSS injection on a Next.js page during server-side rendering - tips and tricks!

I recently started working with next js.

In my _app.tsx page, I have the following code:

import '../styles/antd.css'
import '../styles/globals.css'
import type { AppProps } from 'next/app' 

function MyApp({ Component, pageProps }: AppProps) {
  return (
    <> 
      <Component {...pageProps} /> 
    </>
  )
}

export default MyApp

The issue I am facing is that the styles - import '../styles/antd.css' are being loaded as an external request during production run at

/_next/static/css/fffc165f54adb267.css

. This results in a one second lag during the styles loading. Is there a better way to load styles in my base page without making external requests for styles?

css next.js server-side-rendering

Answer 1

Answer №1

Next.JS documentation discusses the process of importing CSS states.

During production, all CSS files are automatically merged into a single minified .css file.

When using SSR, the markup is transmitted to the user's DOM, with a link tag pointing to your styles. The user must fetch and interpret the styles before rendering, causing the flash effect you mentioned.

To prevent this issue, utilize Styled-JSX.

Styled-JSX ensures that the CSS renders on the server along with other content, resulting in instant loading. See an example in their documentation.

function HelloWorld() {
  return (
    <div>
      Hello world
      <p>scoped!</p>
      <style jsx>{`
        p {
          color: blue;
        }
        div {
          background: red;
        }
        @media (max-width: 600px) {
          div {
            background: blue;
          }
        }
      `}</style>
      <style global jsx>{`
        body {
          background: black;
        }
      `}</style>
    </div>
  )
}

export default HelloWorld

Answer 2

Next.JS documentation discusses the process of importing CSS states.

During production, all CSS files are automatically merged into a single minified .css file.

When using SSR, the markup is transmitted to the user's DOM, with a link tag pointing to your styles. The user must fetch and interpret the styles before rendering, causing the flash effect you mentioned.

To prevent this issue, utilize Styled-JSX.

Styled-JSX ensures that the CSS renders on the server along with other content, resulting in instant loading. See an example in their documentation.

function HelloWorld() {
  return (
    <div>
      Hello world
      <p>scoped!</p>
      <style jsx>{`
        p {
          color: blue;
        }
        div {
          background: red;
        }
        @media (max-width: 600px) {
          div {
            background: blue;
          }
        }
      `}</style>
      <style global jsx>{`
        body {
          background: black;
        }
      `}</style>
    </div>
  )
}

export default HelloWorld

Answer 3

Answer №2

In my current setup with Next.js 13, I have shifted from using the pages/ directory to working exclusively within the /app directory. While server-side rendering (SSR) is functioning perfectly, there has been an issue with styling. Interestingly, removing the "use client"; line resolves all other issues except for styles. I have recently added the styles to the root layout located at: /app/(pages)/layout.tsx. The presence of (pages) in the path structure does not seem to be causing any problems, as it is simply used for organizing folders.

Solution

// snippet from 'next.config.js'
const path = require('path');

module.exports = {
  sassOptions: {
    includePaths: [path.join(__dirname, 'src/styles')],
  },
};

Previously, I had included the `styles` folder instead of correctly pointing to the `src` directory.

The key lesson learned here is that before SSR ("use client"), incorrect directory pointers were still functional.

It was quite challenging to identify this issue, as I initially thought SSR/CSR paths would not play a significant role. However, delving into the code abstraction revealed its importance.

In the long run, it is essential to read and comprehend the code of the packages utilized in a project. This practice enhances coding style and fosters efficient utilization of the packages.

Enhances your coding abilities by witnessing diverse problem-solving techniques worldwide
Facilitates more precise and efficient usage of packages

If anyone is encountering difficulties with applying styles such as .css or .scss/.sass, feel free to reach out for further assistance. Your feedback is valued. Thank you.

https://beta.nextjs.org/docs/styling/sass

Answer 4

In my current setup with Next.js 13, I have shifted from using the pages/ directory to working exclusively within the /app directory. While server-side rendering (SSR) is functioning perfectly, there has been an issue with styling. Interestingly, removing the "use client"; line resolves all other issues except for styles. I have recently added the styles to the root layout located at: /app/(pages)/layout.tsx. The presence of (pages) in the path structure does not seem to be causing any problems, as it is simply used for organizing folders.

Solution

// snippet from 'next.config.js'
const path = require('path');

module.exports = {
  sassOptions: {
    includePaths: [path.join(__dirname, 'src/styles')],
  },
};

Previously, I had included the `styles` folder instead of correctly pointing to the `src` directory.

The key lesson learned here is that before SSR ("use client"), incorrect directory pointers were still functional.

It was quite challenging to identify this issue, as I initially thought SSR/CSR paths would not play a significant role. However, delving into the code abstraction revealed its importance.

In the long run, it is essential to read and comprehend the code of the packages utilized in a project. This practice enhances coding style and fosters efficient utilization of the packages.

Enhances your coding abilities by witnessing diverse problem-solving techniques worldwide
Facilitates more precise and efficient usage of packages

If anyone is encountering difficulties with applying styles such as .css or .scss/.sass, feel free to reach out for further assistance. Your feedback is valued. Thank you.

https://beta.nextjs.org/docs/styling/sass

Answer 5

Answer №3

If you're working with the _app.jsx (or .tsx) file in the pages/ directory, and you're trying to load CSS, keep in mind that it will always be Client-Side Rendered (CSR), not Server-Side Rendered (SSR).

To enable SSR, you need to wrap your Component with a SSRProvider within the pages/ directory.

One popular library for this is from the Adobe team, which you can find here:

Incorporate it like this:

import {SSRProvider, useIsSSR} from 'react-aria'
import type { AppProps } from 'next/app'

import '../styles/antd.css'
import '../styles/globals.css'

function MyApp({ Component, pageProps }: AppProps) {
  return (
    <SSRProvider> 
      <Component {...pageProps} /> 
    </SSRProvider>
  )
}

export default MyApp

In my opinion, the app/ directory is quite reliable. Unless you're working on a critical project with zero downtime requirements affecting thousands of users, consider the switch carefully. Adequate testing can ensure reliability.

For example, using the useIsSSR() hook for testing/debugging purposes:

useOnServer.ts (hook)

import { useIsSSR } from "@react-aria/ssr";

export default function useOnServer() {
  const isServer = useIsSSR();

  console.log(isServer ? "Server" : "Client");
}

This will provide appropriate console.log outputs for both server and client environments, demonstrating isomorphic code capabilities across both sides.

Answer 6

If you're working with the _app.jsx (or .tsx) file in the pages/ directory, and you're trying to load CSS, keep in mind that it will always be Client-Side Rendered (CSR), not Server-Side Rendered (SSR).

To enable SSR, you need to wrap your Component with a SSRProvider within the pages/ directory.

One popular library for this is from the Adobe team, which you can find here:

Incorporate it like this:

import {SSRProvider, useIsSSR} from 'react-aria'
import type { AppProps } from 'next/app'

import '../styles/antd.css'
import '../styles/globals.css'

function MyApp({ Component, pageProps }: AppProps) {
  return (
    <SSRProvider> 
      <Component {...pageProps} /> 
    </SSRProvider>
  )
}

export default MyApp

In my opinion, the app/ directory is quite reliable. Unless you're working on a critical project with zero downtime requirements affecting thousands of users, consider the switch carefully. Adequate testing can ensure reliability.

For example, using the useIsSSR() hook for testing/debugging purposes:

useOnServer.ts (hook)

import { useIsSSR } from "@react-aria/ssr";

export default function useOnServer() {
  const isServer = useIsSSR();

  console.log(isServer ? "Server" : "Client");
}

This will provide appropriate console.log outputs for both server and client environments, demonstrating isomorphic code capabilities across both sides.

Implementing CSS injection on a Next.js page during server-side rendering - tips and tricks!

Answer №1

To prevent this issue, utilize Styled-JSX.

Answer №2

Answer №3

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