vercel · ijjk · Oct 6, 2022 · Oct 4, 2022 · Oct 4, 2022 · Oct 4, 2022
@@ -1964,8 +1964,11 @@ export default async function getBaseWebpackConfig(
         !!config.experimental.sri?.algorithm &&
         new SubresourceIntegrityPlugin(config.experimental.sri.algorithm),
       isClient &&
-        config.experimental.fontLoaders &&
-        new FontLoaderManifestPlugin(),
+        fontLoaderTargets &&
+        new FontLoaderManifestPlugin({
+          appDirEnabled: !!config.experimental.appDir,
+          fontLoaderTargets,
+        }),
       !dev &&
         isClient &&
         new (require('./webpack/plugins/telemetry-plugin').TelemetryPlugin)(

@@ -6,13 +6,41 @@ export type FontLoaderManifest = {
   pages: {
     [path: string]: string[]
   }
+  app: {
+    [moduleRequest: string]: string[]
+  }
 }
 const PLUGIN_NAME = 'FontLoaderManifestPlugin'
 
 // Creates a manifest of all fonts that should be preloaded given a route
 export class FontLoaderManifestPlugin {
+  private appDirEnabled: boolean
+  private fontLoaderTargets: string[]
+
+  constructor(options: {
+    appDirEnabled: boolean
+    fontLoaderTargets: string[]
+  }) {
+    this.appDirEnabled = options.appDirEnabled
+    this.fontLoaderTargets = options.fontLoaderTargets
+  }
+
   apply(compiler: webpack.Compiler) {
     compiler.hooks.make.tap(PLUGIN_NAME, (compilation) => {
+      let fontLoaderModules: webpack.Module[]
+
+      // Get all font loader modules
+      if (this.appDirEnabled) {
+        compilation.hooks.finishModules.tap(PLUGIN_NAME, (modules) => {
+          const modulesArr = Array.from(modules)
+          fontLoaderModules = modulesArr.filter((mod: any) =>
+            this.fontLoaderTargets.some((fontLoaderTarget) =>
+              mod.userRequest?.startsWith(`${fontLoaderTarget}?`)
+            )
+          )
+        })
+      }
+
       compilation.hooks.processAssets.tap(
         {
           name: PLUGIN_NAME,
@@ -21,6 +49,27 @@ export class FontLoaderManifestPlugin {
         (assets: any) => {
           const fontLoaderManifest: FontLoaderManifest = {
             pages: {},
+            app: {},
+          }
+
+          if (this.appDirEnabled) {
+            for (const mod of fontLoaderModules) {
+              const modAssets = Object.keys(mod.buildInfo.assets)
+              const fontFiles: string[] = modAssets.filter((file: string) =>
+                /\.(woff|woff2|eot|ttf|otf)$/.test(file)
+              )
+
+              // Font files ending with .p.(woff|woff2|eot|ttf|otf) are preloaded
+              const preloadedFontFiles: string[] = fontFiles.filter(
+                (file: string) => /\.p.(woff|woff2|eot|ttf|otf)$/.test(file)
+              )
+
+              // Create an entry for the request even if no files should preload. If that's the case a preconnect tag is added.
+              if (fontFiles.length > 0) {
+                fontLoaderManifest.app[(mod as any).userRequest] =
+                  preloadedFontFiles
+              }
+            }
           }
 
           for (const entrypoint of compilation.entrypoints.values()) {

@@ -1,6 +1,7 @@
 import type { IncomingHttpHeaders, IncomingMessage, ServerResponse } from 'http'
 import type { LoadComponentsReturnType } from './load-components'
 import type { ServerRuntime } from '../types'
+import type { FontLoaderManifest } from '../build/webpack/plugins/font-loader-manifest-plugin'
 
 // TODO-APP: change to React.use once it becomes stable
 // @ts-ignore
@@ -139,6 +140,7 @@ export type RenderOptsPartial = {
   runtime?: ServerRuntime
   serverComponents?: boolean
   assetPrefix?: string
+  fontLoaderManifest?: FontLoaderManifest
 }
 
 export type RenderOpts = LoadComponentsReturnType & RenderOptsPartial
@@ -532,6 +534,40 @@ function getCssInlinedLinkTags(
   return [...chunks]
 }
 
+/**
+ * Get inline <link rel="preload" as="font"> tags based on server CSS manifest and font loader manifest. Only used when rendering to HTML.
+ */
+function getPreloadedFontFilesInlineLinkTags(
+  serverComponentManifest: FlightManifest,
+  serverCSSManifest: FlightCSSManifest,
+  fontLoaderManifest: FontLoaderManifest | undefined,
+  filePath?: string
+): string[] {
+  if (!fontLoaderManifest || !filePath) {
+    return []
+  }
+  const layoutOrPageCss =
+    serverCSSManifest[filePath] ||
+    serverComponentManifest.__client_css_manifest__?.[filePath]
+
+  if (!layoutOrPageCss) {
+    return []
+  }
+
+  const fontFiles = new Set<string>()
+
+  for (const css of layoutOrPageCss) {
+    const preloadedFontFiles = fontLoaderManifest.app[css]
+    if (preloadedFontFiles) {
+      for (const fontFile of preloadedFontFiles) {
+        fontFiles.add(fontFile)
+      }
+    }
+  }
+
+  return [...fontFiles]
+}
+
 function getScriptNonceFromHeader(cspHeaderValue: string): string | undefined {
   const directives = cspHeaderValue
     // Directives are split by ';'.
@@ -686,6 +722,7 @@ export async function renderToHTMLOrFlight(
     supportsDynamicHTML,
     ComponentMod,
     dev,
+    fontLoaderManifest,
   } = renderOpts
 
   patchFetch(ComponentMod)
@@ -896,6 +933,12 @@ export async function renderToHTMLOrFlight(
             layoutOrPagePath
           )
         : []
+      const preloadedFontFiles = getPreloadedFontFilesInlineLinkTags(
+        serverComponentManifest,
+        serverCSSManifest!,
+        fontLoaderManifest,
+        layoutOrPagePath
+      )
       const Template = template
         ? await interopDefault(template())
         : React.Fragment
@@ -1074,6 +1117,19 @@ export async function renderToHTMLOrFlight(
 
           return (
             <>
+              {preloadedFontFiles.map((fontFile) => {
+                const ext = /\.(woff|woff2|eot|ttf|otf)$/.exec(fontFile)![1]
+                return (
+                  <link
+                    key={fontFile}
+                    rel="preload"
+                    href={`/_next/${fontFile}`}
+                    as="font"
+                    type={`font/${ext}`}
+                    crossOrigin="anonymous"
+                  />
+                )
+              })}
               {stylesheets
                 ? stylesheets.map((href) => (
                     <link

@@ -230,4 +230,70 @@ describe('app dir next-font', () => {
       ).toBe('normal')
     })
   })
+
+  describe('preload', () => {
+    it('should preload correctly with server components', async () => {
+      const html = await renderViaHTTP(next.url, '/')
+      const $ = cheerio.load(html)
+
+      // Preconnect
+      expect($('link[rel="preconnect"]').length).toBe(0)
+
+      expect($('link[as="font"]').length).toBe(3)
+      expect($('link[as="font"]').get(0).attribs).toEqual({
+        as: 'font',
+        crossorigin: '',
+        href: '/_next/static/media/e9b9dc0d8ba35f48.p.woff2',
+        rel: 'preload',
+        type: 'font/woff2',
+      })
+      expect($('link[as="font"]').get(1).attribs).toEqual({
+        as: 'font',
+        crossorigin: '',
+        href: '/_next/static/media/b2104791981359ae.p.woff2',
+        rel: 'preload',
+        type: 'font/woff2',
+      })
+      expect($('link[as="font"]').get(2).attribs).toEqual({
+        as: 'font',
+        crossorigin: '',
+        href: '/_next/static/media/b61859a50be14c53.p.woff2',
+        rel: 'preload',
+        type: 'font/woff2',
+      })
+    })
+
+    it('should preload correctly with client components', async () => {
+      const html = await renderViaHTTP(next.url, '/client')
+      const $ = cheerio.load(html)
+
+      // Preconnect
+      expect($('link[rel="preconnect"]').length).toBe(0)
+
+      expect($('link[as="font"]').length).toBe(3)
+      // From root layout
+      expect($('link[as="font"]').get(0).attribs).toEqual({
+        as: 'font',
+        crossorigin: '',
+        href: '/_next/static/media/e9b9dc0d8ba35f48.p.woff2',
+        rel: 'preload',
+        type: 'font/woff2',
+      })
+
+      expect($('link[as="font"]').get(1).attribs).toEqual({
+        as: 'font',
+        crossorigin: '',
+        href: '/_next/static/media/e1053f04babc7571.p.woff2',
+        rel: 'preload',
+        type: 'font/woff2',
+      })
+      expect($('link[as="font"]').get(2).attribs).toEqual({
+        as: 'font',
+        crossorigin: '',
+        href: '/_next/static/media/feab2c68f2a8e9a4.p.woff2',
+        rel: 'preload',
+        type: 'font/woff2',
+      })
+    })
+  })
 })
@@ -1,4 +1,4 @@
-import { font3 } from '../fonts/fonts'
+import font3 from '../fonts/font3'
 
 export default function Component() {
   return (

@@ -1,5 +1,5 @@
 'client'
-import { font6 } from '../../fonts/fonts'
+import font6 from '../../fonts/font6'
 
 export default function Component() {
   return (

@@ -1,5 +1,5 @@
 'client'
-import { font4 } from '../../fonts/fonts'
+import font4 from '../../fonts/font4'
 
 export default function Root({ children }) {
   return (

@@ -1,6 +1,6 @@
 'client'
 import Comp from './Comp'
-import { font5 } from '../../fonts/fonts'
+import font5 from '../../fonts/font5'
 
 export default function HomePage() {
   return (

@@ -1,4 +1,4 @@
-import { font1 } from '../fonts/fonts'
+import font1 from '../fonts/font1'
 
 export default function Root({ children }) {
   return (

@@ -1,5 +1,5 @@
 import Comp from './Comp'
-import { font2 } from '../fonts/fonts'
+import font2 from '../fonts/font2'
 
 export default function HomePage() {
   return (

@@ -0,0 +1,5 @@
+import localFont from '@next/font/local'
+
+const font1 = localFont({ src: './font1.woff2', variable: '--font-1' })
+
+export default font1
@@ -0,0 +1,5 @@
+import localFont from '@next/font/local'
+
+export const font2 = localFont({ src: './font2.woff2', variable: '--font-2' })
+
+export default font2
@@ -0,0 +1,9 @@
+import localFont from '@next/font/local'
+
+export const font3 = localFont({
+  src: './font3.woff2',
+  weight: '900',
+  style: 'italic',
+})
+
+export default font3
@@ -0,0 +1,5 @@
+import localFont from '@next/font/local'
+
+export const font4 = localFont({ src: './font4.woff2', weight: '100' })
+
+export default font4
@@ -0,0 +1,9 @@
+import localFont from '@next/font/local'
+
+export const font5 = localFont({
+  src: './font5.woff2',
+  style: 'italic',
+  preload: false,
+})
+
+export default font5
@@ -0,0 +1,5 @@
+import localFont from '@next/font/local'
+
+export const font6 = localFont({ src: './font6.woff2' })
+
+export default font6