fix(eslint-plugin): respect pageExtensions in no-html-link-for-pages rule

packages/eslint-plugin-next/src/rules/no-html-link-for-pages.ts

@@ -10,6 +10,56 @@ import {
   getUrlFromAppDirectory,
 } from '../utils/url'
 
+const DEFAULT_PAGE_EXTENSIONS = ['js', 'jsx', 'ts', 'tsx']
+
+/**
+ * Tries to read `pageExtensions` from `next.config.js` (CJS only).
+ * Returns null if the config cannot be loaded or doesn't define pageExtensions.
+ */
+function loadPageExtensionsFromConfig(rootDir: string): string[] | null {
+  const configFiles = ['next.config.js', 'next.config.ts']
+  for (const configFile of configFiles) {
+    const configPath = path.join(rootDir, configFile)
+    if (!fs.existsSync(configPath)) continue
+    try {
+      // eslint-disable-next-line @typescript-eslint/no-var-requires
+      const config = require(configPath)
+      const resolved = config?.default ?? config
+      if (Array.isArray(resolved?.pageExtensions)) {
+        return resolved.pageExtensions
+      }
+    } catch {
+      // Config may use ESM or have side effects — skip silently
+    }
+  }
+  return null
+}
+
+const loadPageExtensionsFromConfigMemo = new Map<string, string[] | null>()
+
+function getPageExtensions(rootDirs: string[], settings: any): string[] {
+  // 1. ESLint settings take highest priority (explicit user override)
+  const fromSettings = settings?.next?.pageExtensions
+  if (Array.isArray(fromSettings) && fromSettings.length > 0) {
+    return fromSettings
+  }
+
+  // 2. Try to read from next.config.js in each root dir
+  for (const rootDir of rootDirs) {
+    if (!loadPageExtensionsFromConfigMemo.has(rootDir)) {
+      loadPageExtensionsFromConfigMemo.set(
+        rootDir,
+        loadPageExtensionsFromConfig(rootDir)
+      )
+    }
+    const fromConfig = loadPageExtensionsFromConfigMemo.get(rootDir)
+    if (fromConfig) return fromConfig
+  }
+
+  // 3. Fall back to Next.js defaults
+  return DEFAULT_PAGE_EXTENSIONS
+}
+
 const pagesDirWarning = execOnce((pagesDirs) => {
   console.warn(
     `Pages directory cannot be found at ${pagesDirs.join(' or ')}. ` +
@@ -32,8 +82,14 @@ const memoize = <T = any>(fn: (...args: any[]) => T) => {
   }
 }
 
-const cachedGetUrlFromPagesDirectories = memoize(getUrlFromPagesDirectories)
-const cachedGetUrlFromAppDirectory = memoize(getUrlFromAppDirectory)
+const cachedGetUrlFromPagesDirectories = memoize(
+  (urlPrefix: string, dirs: string[], exts: string[]) =>
+    getUrlFromPagesDirectories(urlPrefix, dirs, exts)
+)
+const cachedGetUrlFromAppDirectory = memoize(
+  (urlPrefix: string, dirs: string[], exts: string[]) =>
+    getUrlFromAppDirectory(urlPrefix, dirs, exts)
+)
 
 const url = 'https://nextjs.org/docs/messages/no-html-link-for-pages'
 
@@ -73,6 +129,7 @@ export default defineRule({
     const [customPagesDirectory] = ruleOptions
 
     const rootDirs = getRootDirs(context)
+    const pageExtensions = getPageExtensions(rootDirs, context.settings)
 
     const pagesDirs = (
       customPagesDirectory
@@ -107,8 +164,8 @@ export default defineRule({
       return {}
     }
 
-    const pageUrls = cachedGetUrlFromPagesDirectories('/', foundPagesDirs)
-    const appDirUrls = cachedGetUrlFromAppDirectory('/', foundAppDirs)
+    const pageUrls = cachedGetUrlFromPagesDirectories('/', foundPagesDirs, pageExtensions)
+    const appDirUrls = cachedGetUrlFromAppDirectory('/', foundAppDirs, pageExtensions)
     const allUrlRegex = [...pageUrls, ...appDirUrls]
 
     return {

packages/eslint-plugin-next/src/utils/url.ts

@@ -5,28 +5,46 @@ import * as fs from 'fs'
 // Prevent multiple blocking IO requests that have already been calculated.
 const fsReadDirSyncCache = {}
 
+const DEFAULT_PAGE_EXTENSIONS = ['js', 'jsx', 'ts', 'tsx']
+
+/**
+ * Builds a RegExp that matches filenames with the given extensions.
+ */
+function buildExtensionsRegex(pageExtensions: string[]): RegExp {
+  const escaped = pageExtensions.map((ext) =>
+    ext.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
+  )
+  return new RegExp(`\\.(${escaped.join('|')})$`)
+}
+
 /**
  * Recursively parse directory for page URLs.
  */
-function parseUrlForPages(urlprefix: string, directory: string) {
+function parseUrlForPages(
+  urlprefix: string,
+  directory: string,
+  pageExtensions: string[] = DEFAULT_PAGE_EXTENSIONS
+) {
   fsReadDirSyncCache[directory] ??= fs.readdirSync(directory, {
     withFileTypes: true,
   })
+  const extRegex = buildExtensionsRegex(pageExtensions)
+  const indexRegex = new RegExp(
+    `^index\\.(${pageExtensions.map((e) => e.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')).join('|')})$`
+  )
   const res = []
   fsReadDirSyncCache[directory].forEach((dirent) => {
-    // TODO: this should account for all page extensions
-    // not just js(x) and ts(x)
-    if (/(\.(j|t)sx?)$/.test(dirent.name)) {
-      if (/^index(\.(j|t)sx?)$/.test(dirent.name)) {
-        res.push(
-          `${urlprefix}${dirent.name.replace(/^index(\.(j|t)sx?)$/, '')}`
-        )
+    if (extRegex.test(dirent.name)) {
+      if (indexRegex.test(dirent.name)) {
+        res.push(`${urlprefix}${dirent.name.replace(indexRegex, '')}`)
       }
-      res.push(`${urlprefix}${dirent.name.replace(/(\.(j|t)sx?)$/, '')}`)
+      res.push(`${urlprefix}${dirent.name.replace(extRegex, '')}`)
     } else {
       const dirPath = path.join(directory, dirent.name)
       if (dirent.isDirectory() && !dirent.isSymbolicLink()) {
-        res.push(...parseUrlForPages(urlprefix + dirent.name + '/', dirPath))
+        res.push(
+          ...parseUrlForPages(urlprefix + dirent.name + '/', dirPath, pageExtensions)
+        )
       }
     }
   })
@@ -36,24 +54,35 @@ function parseUrlForPages(urlprefix: string, directory: string) {
 /**
  * Recursively parse app directory for URLs.
  */
-function parseUrlForAppDir(urlprefix: string, directory: string) {
+function parseUrlForAppDir(
+  urlprefix: string,
+  directory: string,
+  pageExtensions: string[] = DEFAULT_PAGE_EXTENSIONS
+) {
   fsReadDirSyncCache[directory] ??= fs.readdirSync(directory, {
     withFileTypes: true,
   })
+  const extRegex = buildExtensionsRegex(pageExtensions)
+  const pageRegex = new RegExp(
+    `^page\\.(${pageExtensions.map((e) => e.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')).join('|')})$`
+  )
+  const layoutRegex = new RegExp(
+    `^layout\\.(${pageExtensions.map((e) => e.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')).join('|')})$`
+  )
   const res = []
   fsReadDirSyncCache[directory].forEach((dirent) => {
-    // TODO: this should account for all page extensions
-    // not just js(x) and ts(x)
-    if (/(\.(j|t)sx?)$/.test(dirent.name)) {
-      if (/^page(\.(j|t)sx?)$/.test(dirent.name)) {
-        res.push(`${urlprefix}${dirent.name.replace(/^page(\.(j|t)sx?)$/, '')}`)
-      } else if (!/^layout(\.(j|t)sx?)$/.test(dirent.name)) {
-        res.push(`${urlprefix}${dirent.name.replace(/(\.(j|t)sx?)$/, '')}`)
+    if (extRegex.test(dirent.name)) {
+      if (pageRegex.test(dirent.name)) {
+        res.push(`${urlprefix}${dirent.name.replace(pageRegex, '')}`)
+      } else if (!layoutRegex.test(dirent.name)) {
+        res.push(`${urlprefix}${dirent.name.replace(extRegex, '')}`)
       }
     } else {
       const dirPath = path.join(directory, dirent.name)
       if (dirent.isDirectory(dirPath) && !dirent.isSymbolicLink()) {
-        res.push(...parseUrlForPages(urlprefix + dirent.name + '/', dirPath))
+        res.push(
+          ...parseUrlForPages(urlprefix + dirent.name + '/', dirPath, pageExtensions)
+        )
       }
     }
   })
@@ -136,13 +165,16 @@ export function normalizeAppPath(route: string) {
  */
 export function getUrlFromPagesDirectories(
   urlPrefix: string,
-  directories: string[]
+  directories: string[],
+  pageExtensions: string[] = DEFAULT_PAGE_EXTENSIONS
 ) {
   return Array.from(
     // De-duplicate similar pages across multiple directories.
     new Set(
       directories
-        .flatMap((directory) => parseUrlForPages(urlPrefix, directory))
+        .flatMap((directory) =>
+          parseUrlForPages(urlPrefix, directory, pageExtensions)
+        )
         .map(
           // Since the URLs are normalized we add `^` and `$` to the RegExp to make sure they match exactly.
           (url) => `^${normalizeURL(url)}$`
@@ -156,13 +188,16 @@ export function getUrlFromPagesDirectories(
 
 export function getUrlFromAppDirectory(
   urlPrefix: string,
-  directories: string[]
+  directories: string[],
+  pageExtensions: string[] = DEFAULT_PAGE_EXTENSIONS
 ) {
   return Array.from(
     // De-duplicate similar pages across multiple directories.
     new Set(
       directories
-        .map((directory) => parseUrlForAppDir(urlPrefix, directory))
+        .map((directory) =>
+          parseUrlForAppDir(urlPrefix, directory, pageExtensions)
+        )
         .flat()
         .map(
           // Since the URLs are normalized we add `^` and `$` to the RegExp to make sure they match exactly.