feat: add output: export support for appDir

packages/next/src/build/index.ts

@@ -1282,6 +1282,7 @@ export default async function build(
               enableUndici: config.experimental.enableUndici,
               locales: config.i18n?.locales,
               defaultLocale: config.i18n?.defaultLocale,
+              nextConfigOutput: config.output,
             })
         )
 
@@ -1466,6 +1467,7 @@ export default async function build(
                           isrFlushToDisk: config.experimental.isrFlushToDisk,
                           maxMemoryCacheSize:
                             config.experimental.isrMemoryCacheSize,
+                          nextConfigOutput: config.output,
                         })
                       }
                     )

packages/next/src/build/utils.ts

@@ -1329,6 +1329,7 @@ export async function isPageStatic({
   isrFlushToDisk,
   maxMemoryCacheSize,
   incrementalCacheHandlerPath,
+  nextConfigOutput,
 }: {
   page: string
   distDir: string
@@ -1347,6 +1348,7 @@ export async function isPageStatic({
   isrFlushToDisk?: boolean
   maxMemoryCacheSize?: number
   incrementalCacheHandlerPath?: string
+  nextConfigOutput: 'standalone' | 'export'
 }): Promise<{
   isStatic?: boolean
   isAmpOnly?: boolean
@@ -1480,6 +1482,16 @@ export async function isPageStatic({
           {}
         )
 
+        if (nextConfigOutput === 'export') {
+          if (!appConfig.dynamic || appConfig.dynamic === 'auto') {
+            appConfig.dynamic = 'error'
+          } else if (appConfig.dynamic === 'force-dynamic') {
+            throw new Error(
+              `export const dynamic = "force-dynamic" on page "${page}" cannot be used with "output: export". See more info here: https://nextjs.org/docs/advanced-features/static-html-export`
+            )
+          }
+        }
+
         if (appConfig.dynamic === 'force-dynamic') {
           appConfig.revalidate = 0
         }

packages/next/src/build/webpack-config.ts

@@ -319,6 +319,7 @@ export function getDefineEnv({
     }),
     'process.env.__NEXT_ROUTER_BASEPATH': JSON.stringify(config.basePath),
     'process.env.__NEXT_HAS_REWRITES': JSON.stringify(hasRewrites),
+    'process.env.__NEXT_CONFIG_OUTPUT': JSON.stringify(config.output),
     'process.env.__NEXT_I18N_SUPPORT': JSON.stringify(!!config.i18n),
     'process.env.__NEXT_I18N_DOMAINS': JSON.stringify(config.i18n?.domains),
     'process.env.__NEXT_ANALYTICS_ID': JSON.stringify(config.analyticsId),

packages/next/src/client/components/router-reducer/fetch-server-response.ts

@@ -35,7 +35,16 @@ export async function fetchServerResponse(
   }
 
   try {
-    const res = await fetch(url.toString(), {
+    let fetchUrl = url
+    if (process.env.__NEXT_CONFIG_OUTPUT === 'export') {
+      fetchUrl = new URL(url) // clone
+      if (fetchUrl.pathname.endsWith('/')) {
+        fetchUrl.pathname += 'index.txt'
+      } else {
+        fetchUrl.pathname += '.txt'
+      }
+    }
+    const res = await fetch(fetchUrl, {
       // Backwards compat for older browsers. `same-origin` is the default in modern browsers.
       credentials: 'same-origin',
       headers,
@@ -44,8 +53,14 @@ export async function fetchServerResponse(
       ? urlToUrlWithoutFlightMarker(res.url)
       : undefined
 
-    const isFlightResponse =
-      res.headers.get('content-type') === RSC_CONTENT_TYPE_HEADER
+    const contentType = res.headers.get('content-type') || ''
+    let isFlightResponse = contentType === RSC_CONTENT_TYPE_HEADER
+
+    if (process.env.__NEXT_CONFIG_OUTPUT === 'export') {
+      if (!isFlightResponse) {
+        isFlightResponse = contentType.startsWith('text/plain')
+      }
+    }
 
     // If fetch returns something different than flight response handle it like a mpa navigation
     if (!isFlightResponse) {

packages/next/src/export/index.ts

@@ -31,6 +31,7 @@ import {
   PRERENDER_MANIFEST,
   SERVER_DIRECTORY,
   SERVER_REFERENCE_MANIFEST,
+  APP_PATH_ROUTES_MANIFEST,
 } from '../shared/lib/constants'
 import loadConfig from '../server/config'
 import { ExportPathMap, NextConfigComplete } from '../server/config-shared'
@@ -51,6 +52,9 @@ import {
   overrideBuiltInReactPackages,
 } from '../build/webpack/require-hook'
 import { MiddlewareManifest } from '../build/webpack/plugins/middleware-plugin'
+import { isAppRouteRoute } from '../lib/is-app-route-route'
+import { isAppPageRoute } from '../lib/is-app-page-route'
+import isError from '../lib/is-error'
 
 loadRequireHook()
 if (process.env.NEXT_PREBUNDLED_REACT) {
@@ -238,6 +242,23 @@ export default async function exportApp(
       prerenderManifest = require(join(distDir, PRERENDER_MANIFEST))
     } catch (_) {}
 
+    let appRoutePathManifest: Record<string, string> | undefined = undefined
+    try {
+      appRoutePathManifest = require(join(distDir, APP_PATH_ROUTES_MANIFEST))
+    } catch (err) {
+      if (
+        isError(err) &&
+        (err.code === 'ENOENT' || err.code === 'MODULE_NOT_FOUND')
+      ) {
+        // the manifest doesn't exist which will happen when using
+        // "pages" dir instead of "app" dir.
+        appRoutePathManifest = undefined
+      } else {
+        // the manifest is malformed (invalid json)
+        throw err
+      }
+    }
+
     const excludedPrerenderRoutes = new Set<string>()
     const pages = options.pages || Object.keys(pagesManifest)
     const defaultPathMap: ExportPathMap = {}
@@ -269,6 +290,25 @@ export default async function exportApp(
       defaultPathMap[page] = { page }
     }
 
+    const mapAppRouteToPage = new Map<string, string>()
+    if (!options.buildExport && appRoutePathManifest) {
+      for (const [pageName, routePath] of Object.entries(
+        appRoutePathManifest
+      )) {
+        mapAppRouteToPage.set(routePath, pageName)
+        if (
+          isAppPageRoute(pageName) &&
+          !prerenderManifest?.routes[routePath] &&
+          !prerenderManifest?.dynamicRoutes[routePath]
+        ) {
+          defaultPathMap[routePath] = {
+            page: pageName,
+            _isAppDir: true,
+          }
+        }
+      }
+    }
+
     // Initialize the output directory
     const outDir = options.outdir
 
@@ -711,7 +751,10 @@ export default async function exportApp(
       await Promise.all(
         Object.keys(prerenderManifest.routes).map(async (route) => {
           const { srcRoute } = prerenderManifest!.routes[route]
-          const pageName = srcRoute || route
+          const appPageName = mapAppRouteToPage.get(srcRoute || '')
+          const pageName = appPageName || srcRoute || route
+          const isAppPath = Boolean(appPageName)
+          const isAppRouteHandler = appPageName && isAppRouteRoute(appPageName)
 
           // returning notFound: true from getStaticProps will not
           // output html/json files during the build
@@ -720,7 +763,7 @@ export default async function exportApp(
           }
           route = normalizePagePath(route)
 
-          const pagePath = getPagePath(pageName, distDir, undefined, false)
+          const pagePath = getPagePath(pageName, distDir, undefined, isAppPath)
           const distPagesDir = join(
             pagePath,
             // strip leading / and then recurse number of nested dirs
@@ -733,6 +776,15 @@ export default async function exportApp(
           )
 
           const orig = join(distPagesDir, route)
+          const handlerSrc = `${orig}.body`
+          const handlerDest = join(outDir, route)
+
+          if (isAppRouteHandler && (await exists(handlerSrc))) {
+            await promises.mkdir(dirname(handlerDest), { recursive: true })
+            await promises.copyFile(handlerSrc, handlerDest)
+            return
+          }
+
           const htmlDest = join(
             outDir,
             `${route}${
@@ -743,13 +795,20 @@ export default async function exportApp(
             outDir,
             `${route}.amp${subFolders ? `${sep}index` : ''}.html`
           )
-          const jsonDest = join(pagesDataDir, `${route}.json`)
+          const jsonDest = isAppPath
+            ? join(
+                outDir,
+                `${route}${
+                  subFolders && route !== '/index' ? `${sep}index` : ''
+                }.txt`
+              )
+            : join(pagesDataDir, `${route}.json`)
 
           await promises.mkdir(dirname(htmlDest), { recursive: true })
           await promises.mkdir(dirname(jsonDest), { recursive: true })
 
           const htmlSrc = `${orig}.html`
-          const jsonSrc = `${orig}.json`
+          const jsonSrc = `${orig}${isAppPath ? '.rsc' : '.json'}`
 
           await promises.copyFile(htmlSrc, htmlDest)
           await promises.copyFile(jsonSrc, jsonDest)

packages/next/src/server/config-shared.ts

@@ -240,7 +240,11 @@ export interface ExperimentalConfig {
 }
 
 export type ExportPathMap = {
-  [path: string]: { page: string; query?: Record<string, string | string[]> }
+  [path: string]: {
+    page: string
+    query?: Record<string, string | string[]>
+    _isAppDir?: boolean
+  }
 }
 
 /**

test/integration/app-dir-export/app/another/[slug]/page.js

@@ -0,0 +1,20 @@
+import Link from 'next/link'
+
+export const dynamic = 'force-static'
+
+export function generateStaticParams() {
+  return [{ slug: 'first' }, { slug: 'second' }]
+}
+
+export default function Page({ params }) {
+  return (
+    <main>
+      <h1>{params.slug}</h1>
+      <ul>
+        <li>
+          <Link href="/another">Visit another page</Link>
+        </li>
+      </ul>
+    </main>
+  )
+}

test/integration/app-dir-export/app/another/page.js

@@ -0,0 +1,26 @@
+import Link from 'next/link'
+
+export default function Another() {
+  return (
+    <main>
+      <h1>Another</h1>
+      <ul>
+        <li>
+          <Link href="/">Visit the home page</Link>
+        </li>
+        <li>
+          <Link href="/another">another page</Link>
+        </li>
+        <li>
+          <Link href="/another/first">another first page</Link>
+        </li>
+        <li>
+          <Link href="/another/second">another second page</Link>
+        </li>
+        <li>
+          <Link href="/image-import">image import page</Link>
+        </li>
+      </ul>
+    </main>
+  )
+}

test/integration/app-dir-export/app/api/json/route.js

@@ -0,0 +1,3 @@
+export async function GET() {
+  return Response.json({ answer: 42 })
+}

test/integration/app-dir-export/app/api/txt/route.js

@@ -0,0 +1,3 @@
+export async function GET() {
+  return new Response('this is plain text')
+}

test/integration/app-dir-export/app/image-import/page.js

@@ -0,0 +1,18 @@
+import Link from 'next/link'
+import img from './test.png'
+
+export default function ImageImport() {
+  return (
+    <main>
+      <h1>Image Import</h1>
+      <ul>
+        <li>
+          <Link href="/">Visit the home page</Link>
+        </li>
+        <li>
+          <a href={img.src}>View the image</a>
+        </li>
+      </ul>
+    </main>
+  )
+}

test/integration/app-dir-export/app/layout.js

@@ -0,0 +1,7 @@
+export default function RootLayout({ children }) {
+  return (
+    <html lang="en">
+      <body>{children}</body>
+    </html>
+  )
+}

test/integration/app-dir-export/app/page.js

@@ -0,0 +1,26 @@
+import Link from 'next/link'
+
+export default function Home() {
+  return (
+    <main>
+      <h1>Home</h1>
+      <ul>
+        <li>
+          <Link href="/another">another no trailingslash</Link>
+        </li>
+        <li>
+          <Link href="/another/">another has trailingslash</Link>
+        </li>
+        <li>
+          <Link href="/another/first">another first page</Link>
+        </li>
+        <li>
+          <Link href="/another/second">another second page</Link>
+        </li>
+        <li>
+          <Link href="/image-import">image import page</Link>
+        </li>
+      </ul>
+    </main>
+  )
+}

test/integration/app-dir-export/app/robots.txt

@@ -0,0 +1,2 @@
+User-agent: *
+Allow: /

test/integration/app-dir-export/next.config.js

@@ -0,0 +1,13 @@
+/** @type {import('next').NextConfig} */
+const nextConfig = {
+  output: 'export',
+  trailingSlash: true,
+  experimental: {
+    appDir: true,
+  },
+  generateBuildId() {
+    return 'test-build-id'
+  },
+}
+
+module.exports = nextConfig