@next/next/no-page-custom-font

A font <link> in one page only loads for that page. Other pages that use the font show a fallback instead. In pages/_document.js, the same <link> is part of every page.

The rule looks at <link> elements with an href that starts with https://fonts.googleapis.com/css. It reports them in every file that isn't named _document.*. In _document.*, it reports them if they aren't inside the default export.

Configure#

Off by default. To turn it on:

bunfig.toml

[lint.rules]
"@next/next/no-page-custom-font" = "error" # or "warn"

Examples#

pages/index.jsx1 problem

import Head from "next/head";

export default function Home() {
  return (
    <Head>
      <link href="https://fonts.googleapis.com/css2?family=Inter&display=optional" rel="stylesheet" />
    </Head>
  );
}

Here the file is pages/_document.jsx, but the element is in a helper, not in the exported document:

pages/_document.jsx1 problem

import { Head, Html, Main, NextScript } from "next/document";

function Fonts() {
  return <link href="https://fonts.googleapis.com/css2?family=Inter&display=optional" rel="stylesheet" />;
}

export default function Document() {
  return (
    <Html>
      <Head>
        <Fonts />
      </Head>
      <body>
        <Main />
        <NextScript />
      </body>
    </Html>
  );
}

pages/_document.jsxNo problems

import { Head, Html, Main, NextScript } from "next/document";

export default function Document() {
  return (
    <Html>
      <Head>
        <link href="https://fonts.googleapis.com/css2?family=Inter&display=optional" rel="stylesheet" />
      </Head>
      <body>
        <Main />
        <NextScript />
      </body>
    </Html>
  );
}

When not to use it#

The App Router has no _document.js, so a font <link> in app/layout.js is reported too. Load the font with next/font, or turn the rule off.

app/layout.jsx1 problem

export default function RootLayout({ children }) {
  return (
    <html lang="en">
      <head>
        <link href="https://fonts.googleapis.com/css2?family=Inter&display=optional" rel="stylesheet" />
      </head>
      <body>{children}</body>
    </html>
  );
}