diff --git a/.changeset/honest-guests-shout.md b/.changeset/honest-guests-shout.md
new file mode 100644
index 0000000000..9a67a27d4d
--- /dev/null
+++ b/.changeset/honest-guests-shout.md
@@ -0,0 +1,5 @@
+---
+'nextra': patch
+---
+
+fix TypeError: Cannot read properties of undefined (reading 'data')
diff --git a/.eslintrc.cjs b/.eslintrc.cjs
index 8767d37314..2b25ed9e09 100644
--- a/.eslintrc.cjs
+++ b/.eslintrc.cjs
@@ -9,7 +9,7 @@ module.exports = {
   overrides: [
     {
       // TODO: enable for `nextra-theme-blog` also
-      files: 'packages/nextra-theme-docs/**/*.{js,jsx,mjs,cjs,ts,tsx,mts,cts}',
+      files: 'packages/nextra-theme-docs/**/*',
       plugins: ['typescript-sort-keys'],
       rules: {
         'no-restricted-imports': [
@@ -20,6 +20,22 @@ module.exports = {
           }
         ]
       }
+    },
+    {
+      files: 'packages/nextra/src/**/*',
+      rules: {
+        'no-restricted-imports': [
+          'error',
+          {
+            patterns: [
+              {
+                group: ['fs', 'node:fs'],
+                message: 'Use `graceful-fs` instead'
+              }
+            ]
+          }
+        ]
+      }
     }
   ]
 }
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 948d933e87..dbed838e41 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,11 +6,12 @@ on:
 
 jobs:
   test:
-    name: Test
+    name: Test (${{matrix.os}})
     runs-on: ubuntu-latest
     strategy:
       matrix:
         node-version: [16, 18]
+        os: [ubuntu-latest, windows-latest]
 
     steps:
       - name: Checkout Master
diff --git a/examples/swr-site/theme.config.tsx b/examples/swr-site/theme.config.tsx
index a0b1cb180d..71e76585d3 100644
--- a/examples/swr-site/theme.config.tsx
+++ b/examples/swr-site/theme.config.tsx
@@ -102,8 +102,8 @@ const config: DocsThemeConfig = {
     },
   },
   feedback: {
-    labels: "feedback",
     content: "Question? Give us feedback →",
+    labels: "feedback",
   },
   footer: {
     text() {
@@ -121,9 +121,6 @@ const config: DocsThemeConfig = {
     },
   },
   gitTimestamp: "Last updated on",
-  project: {
-    link: "https://github.com/vercel/swr",
-  },
   head() {
     const config = useConfig();
     const description =
@@ -196,6 +193,9 @@ const config: DocsThemeConfig = {
   nextThemes: {
     defaultTheme: "dark",
   },
+  project: {
+    link: "https://github.com/vercel/swr",
+  },
   sidebar: {
     defaultMenuCollapsed: true,
     titleComponent: ({ title }) => (
diff --git a/package.json b/package.json
index 97e769b7f8..b384ce77fb 100644
--- a/package.json
+++ b/package.json
@@ -4,7 +4,7 @@
     "dev": "turbo run dev",
     "build": "turbo run build:tailwind build --filter=./packages/*",
     "types:check": "turbo run types:check",
-    "lint": "eslint --ignore-path .gitignore .",
+    "lint": "eslint --ignore-path .gitignore --ext js,jsx,mjs,cjs,ts,tsx,mts,cts .",
     "dev:core": "turbo run dev --filter=nextra... --filter=!docs",
     "dev:theme-blog": "turbo run dev --filter=blog... --filter=!docs",
     "dev:theme-docs": "turbo run dev --filter=swr-site... --filter=!docs",
diff --git a/packages/nextra/__test__/compile.test.ts b/packages/nextra/__test__/compile.test.ts
index b68289f9f9..f5541b92ca 100644
--- a/packages/nextra/__test__/compile.test.ts
+++ b/packages/nextra/__test__/compile.test.ts
@@ -1,7 +1,8 @@
+import fs from 'node:fs/promises'
+import path from 'node:path'
 import { compileMdx } from '../src/compile'
 import { it, describe, expect } from 'vitest'
-import path from 'path'
-import { promises as fs } from 'fs'
+import { CWD } from '../src/constants'
 
 type Name =
   | 'code-h1.mdx'
@@ -11,13 +12,7 @@ type Name =
   | 'static-h1.mdx'
 
 function loadFixture(name: Name) {
-  const filePath = path.join(
-    process.cwd(),
-    '__test__',
-    'fixture',
-    'headings',
-    name
-  )
+  const filePath = path.join(CWD, '__test__', 'fixture', 'headings', name)
   return fs.readFile(filePath, 'utf8')
 }
 
diff --git a/packages/nextra/__test__/context.test.ts b/packages/nextra/__test__/context.test.ts
index 676d0adce2..b5e2ae1421 100644
--- a/packages/nextra/__test__/context.test.ts
+++ b/packages/nextra/__test__/context.test.ts
@@ -5,11 +5,19 @@ import {
   getPagesUnderRoute
 } from '../src/context'
 import { collectFiles } from '../src/plugin'
+import { CWD } from '../src/constants'
 import path from 'node:path'
 
 describe('context', () => {
   beforeAll(async () => {
-    const PAGES_DIR = path.join(process.cwd(), '../../examples/swr-site/pages')
+    const PAGES_DIR = path.join(
+      CWD,
+      '..',
+      '..',
+      'examples',
+      'swr-site',
+      'pages'
+    )
     const { items } = await collectFiles(PAGES_DIR)
     globalThis.__nextra_internal__ = {
       pageMap: items,
diff --git a/packages/nextra/__test__/page-map.test.ts b/packages/nextra/__test__/page-map.test.ts
index 82307352eb..97e0f18c32 100644
--- a/packages/nextra/__test__/page-map.test.ts
+++ b/packages/nextra/__test__/page-map.test.ts
@@ -5,7 +5,7 @@ import { collectFiles } from '../src/plugin'
 import { FileMap, PageMapItem } from '../src/types'
 import { CWD } from '../src/constants'
 
-const PAGES_DIR = path.join(CWD, '../../examples/swr-site/pages')
+const PAGES_DIR = path.join(CWD, '..', '..', 'examples', 'swr-site', 'pages')
 const filePath = (name: string) => path.join(PAGES_DIR, name)
 
 const defaultLocale = 'en-US'
@@ -26,7 +26,11 @@ describe('Page Process', () => {
       fileMap,
       defaultLocale
     })
-    expect([indexData.pageMap, indexData.route, indexData.title]).toMatchSnapshot()
+    expect([
+      indexData.pageMap,
+      indexData.route,
+      indexData.title
+    ]).toMatchSnapshot()
 
     const gettingStartData = await getPageMap({
       filePath: filePath('docs/getting-started.en-US.mdx'),
@@ -44,7 +48,11 @@ describe('Page Process', () => {
       fileMap,
       defaultLocale
     })
-    expect([indexData.pageMap, indexData.route, indexData.title]).toMatchSnapshot()
+    expect([
+      indexData.pageMap,
+      indexData.route,
+      indexData.title
+    ]).toMatchSnapshot()
 
     const gettingStartData = await getPageMap({
       filePath: filePath('docs/getting-started.zh-CN.mdx'),
diff --git a/packages/nextra/src/constants.ts b/packages/nextra/src/constants.ts
index fffd624052..42e297b6b6 100644
--- a/packages/nextra/src/constants.ts
+++ b/packages/nextra/src/constants.ts
@@ -21,8 +21,8 @@ export const MARKDOWN_EXTENSIONS = ['md', 'mdx'] as const
 
 export const PUBLIC_DIR = path.join(CWD, 'public')
 
-export const CACHE_DIR = path.join(CWD, '.next/cache')
+export const CACHE_DIR = path.join(CWD, '.next', 'cache')
 
-export const ASSET_DIR = path.join(CWD, '.next/static/chunks')
+export const ASSET_DIR = path.join(CWD, '.next', 'static', 'chunks')
 
 export const EXTERNAL_URL_REGEX = /^https?:\/\//
diff --git a/packages/nextra/src/loader.ts b/packages/nextra/src/loader.ts
index b711ea6eec..248c2b2b2d 100644
--- a/packages/nextra/src/loader.ts
+++ b/packages/nextra/src/loader.ts
@@ -17,8 +17,9 @@ import {
   DEFAULT_LOCALE,
   OFFICIAL_THEMES,
   MARKDOWN_EXTENSION_REGEX,
-  CWD,
+  CWD
 } from './constants'
+
 const PAGES_DIR = findPagesDir(CWD).pages
 
 // TODO: create this as a webpack plugin.
@@ -179,7 +180,7 @@ export default MDXContent`.trimStart()
 
   const pageOpts: Omit<PageOpts, 'title'> = {
     filePath: slash(path.relative(CWD, mdxPath)),
-    route: slash(route),
+    route,
     frontMatter,
     pageMap,
     headings,
diff --git a/packages/nextra/src/page-map.ts b/packages/nextra/src/page-map.ts
index 99bdedfd4d..4ae185ccc6 100644
--- a/packages/nextra/src/page-map.ts
+++ b/packages/nextra/src/page-map.ts
@@ -24,13 +24,13 @@ export function getPageMap({
   const { locale } = parseFileName(filePath)
   const pageItem = fileMap[filePath as MdxPath]
 
-  const metaPath = path.dirname(filePath)
   const metaFilename = locale
     ? META_FILENAME.replace('.', `.${locale}.`)
     : META_FILENAME
+  const metaDir = path.dirname(filePath)
+  const metaPath = path.join(metaDir, metaFilename) as MetaJsonPath
 
-  const pageMeta =
-    fileMap[`${metaPath}/${metaFilename}` as MetaJsonPath].data[pageItem.name]
+  const pageMeta = fileMap[metaPath].data[pageItem.name]
 
   return {
     pageMap: locale
diff --git a/packages/nextra/src/plugin.ts b/packages/nextra/src/plugin.ts
index 31fdd7441d..1fa5c4e104 100644
--- a/packages/nextra/src/plugin.ts
+++ b/packages/nextra/src/plugin.ts
@@ -49,7 +49,7 @@ export async function collectFiles(
   const files = await readdir(dir, { withFileTypes: true })
 
   const promises = files.map(async f => {
-    const filePath = path.resolve(dir, f.name)
+    const filePath = path.join(dir, f.name)
     const { name, locale, ext } = parseFileName(filePath)
     const fileRoute = slash(path.join(route, name.replace(/^index$/, '')))
 
diff --git a/packages/nextra/src/utils.ts b/packages/nextra/src/utils.ts
index 48f825a2b0..097995a35f 100644
--- a/packages/nextra/src/utils.ts
+++ b/packages/nextra/src/utils.ts
@@ -1,5 +1,4 @@
 import path from 'node:path'
-import fs from 'graceful-fs'
 import { LOCALE_REGEX } from './constants'
 import { Meta } from './types'