[docs] Add precision about pageExtensions (#40016)

yoannmoinet · ijjk · web-flow · commit 1b61d1f5df3e · 2022-08-28T21:34:59.000Z
Adding a precision because when you change the `pageExtensions` configuration in `next.config.js`, `middleware.ts` isn't recognized anymore. Took me some time to debug this one, not sure if it should be considered a bug or just lack of documentation. I'll let you be the judge of that. ## Documentation / Examples - [x] Make sure the linting passes by running `pnpm lint` - [x] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples) Co-authored-by: JJ Kasper <22380829+ijjk@users.noreply.github.com>
diff --git a/docs/advanced-features/middleware.md b/docs/advanced-features/middleware.md
@@ -50,6 +50,8 @@ export const config = {
 }
 ```
 
+> **Note** the `pageExtensions` config affects middleware as well, [see related documentation here](/docs/api-reference/next.config.js/custom-page-extensions.md).
+
 ## Matching Paths
 
 Middleware will be invoked for **every route in your project**. The following is the execution order:

Original file line number	Diff line number	Diff line change
`@@ -50,6 +50,8 @@ export const config = {`
`50`	`50`	`}`
`51`	`51`	```
`52`	`52`
	`53`	+> Note the `pageExtensions` config affects middleware as well, [see related documentation here](/docs/api-reference/next.config.js/custom-page-extensions.md).
	`54`	`+`
`53`	`55`	`## Matching Paths`
`54`	`56`
`55`	`57`	`Middleware will be invoked for every route in your project. The following is the execution order:`