The best way to load and use Google Fonts in Next.js + Tailwind
Tags: nextjs, css, javascript, performance
Published: 2021-02-15 19:06:20

I was setting up a new project today with Next.js and tailwindcss, and I had to use Roboto as a font. 

Since it's a Google Font, I was looking into the best way to load a font from an external URL (since the fonts are available through a CDN, I don't bother hosting them myself).

The following article explains this very thoroughly: https://csswizardry.com/2020/05/the-fastest-google-fonts.

From this article you can derive the following snippet:
```html
<link rel="preconnect"
      href="https://fonts.gstatic.com"
      crossorigin />

<!-- [2] -->
<link rel="preload"
      as="style"
      href="https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap" />

<!-- [3] -->
<link rel="stylesheet"
      href="https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap"
      media="print" onload="this.media='all'" />

<!-- [4] -->
<noscript>
  <link rel="stylesheet"
        href="https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap" />
</noscript>
``` 

<b>Also note how I only include the weights I'm going to be using (400 & 700) to reduce the size of the font we're loading.</b>

So, how do we implement the above snippet into our Next.js application?
That's quite simple! 
In your `/pages` folder, you should have a `_document.js/.tsx` file. 
In this file, we can easily adapt the `<head>` section using the `next/head` module. This will be applied on every page by Next.js.

```tsx
import Document, {
  DocumentContext,
  Html,
  Head,
  Main,
  NextScript,
} from 'next/document'

class MyDocument extends Document {
  static async getInitialProps(ctx: DocumentContext) {
    const initialProps = await Document.getInitialProps(ctx)

    return initialProps
  }

  render() {
    return (
      <Html>
        <Head>
          <link
            rel="preconnect"
            href="https://fonts.gstatic.com"
            crossOrigin="true"
          />
          <link
            rel="preload"
            as="style"
            href="https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap"
          />
          <link
            rel="stylesheet"
            href="https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap"
            media="print"
            onLoad="this.media='all'"
          />
          <noscript>
            <link
              rel="stylesheet"
              href="https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap"
            />
          </noscript>
        </Head>
        <body>
          <Main />
          <NextScript />
        </body>
      </Html>
    )
  }
}

export default MyDocument
```

Now the Next.js part is done. The font is being loaded, yay!
The next and final part is actually using the font in Tailwind, and applying it to all our sans-serif text (since Roboto is a sans-serif font).

This is super easy in Tailwind, this just requires an extension of the default theme:

```javascript
const defaultTheme = require('tailwindcss/defaultTheme')

module.exports = {
  theme: {
    extend: {
      fontFamily: {
        sans: ['Roboto', ...defaultTheme.fontFamily.sans],
      },
    },
  },
  variants: {
    extend: {},
  },
  plugins: [],
}
```

I only needed to add the `sans` property of the `fontFamily` object to include the Roboto font, and add the other sans-serif fonts from the default theme as fallbacks.

There you have it! Optimized font loading in your Next.js application with Tailwind :-) 
Enjoy.