Custom Page Extensions

Aimed at modules like @next/mdx, which adds support for pages ending with .mdx. You can configure the extensions looked for in the pages directory when resolving pages.

Open next.config.js and add the pageExtensions config:

  1. module.exports = {
  2.   pageExtensions: ['mdx', 'md', 'jsx', 'js', 'tsx', 'ts'],
  3. }

Note: The default value of pageExtensions is [‘tsx’, ‘ts’, ‘jsx’, ‘js’].

Note: configuring pageExtensions also affects _document.js, _app.js, middleware.js as well as files under pages/api/. For example, setting pageExtensions: ['page.tsx', 'page.ts'] means the following files: _document.tsx, _app.tsx, middleware.ts, pages/users.tsx and pages/api/users.ts will have to be renamed to _document.page.tsx, _app.page.tsx, middleware.page.ts, pages/users.page.tsx and pages/api/users.page.ts respectively.

Including non-page files in the pages directory

To colocate test files, generated files, or other files used by components in the pages directory, you can prefix the extensions with something like page.

Open next.config.js and add the pageExtensions config:

  1. module.exports = {
  2.   pageExtensions: ['page.tsx', 'page.ts', 'page.jsx', 'page.js'],
  3. }

Then rename your pages to have a file extension that includes .page (ex. rename MyPage.tsx to MyPage.page.tsx).

Note: Make sure you also rename _document.js, _app.js, middleware.js, as well as files under pages/api/.

Without this config, Next.js assumes every tsx/ts/jsx/js file in the pages directory is a page or API route, and may expose unintended routes vulnerable to denial of service attacks, or throw an error like the following when building the production bundle:

  1. Build error occurred
  2. Error: Build optimization failed: found pages without a React Component as default export in
  3. pages/MyPage.generated
  4. pages/MyPage.test
  6. See https://nextjs.org/docs/messages/page-without-valid-component for more info.

Introduction to next.config.jsLearn more about the configuration file used by Next.js.