docs(errors): update invalid page config

errors/invalid-page-config.md

@@ -1,12 +1,13 @@
-# Invalid Page Config
+# Invalid Page / API Route Config
 
 #### Why This Error Occurred
 
-In one of your pages you did `export const config` with an invalid value.
+In one of your pages or API Routes you did `export const config` with an invalid value.
 
 #### Possible Ways to Fix It
 
 The page's config must be an object initialized directly when being exported and not modified dynamically.
+The config object must only contains static constant literals without expressions.
 
 This is not allowed
 
@@ -23,17 +24,50 @@ config.amp = true
 
 This is not allowed
 
+```js
+export const config = {
+  amp: 1 + 1 > 2,
+}
+```
+
+This is not allowed
+
 ```js
 export { config } from '../config'
 ```
 
+This is not allowed
+
+```js
+export const config = {
+  runtime: `n${'od'}ejs`,
+}
+```
+
 This is allowed
 
 ```js
 export const config = { amp: true }
 ```
 
+This is allowed
+
+```js
+export const config = {
+  runtime: 'nodejs',
+}
+```
+
+This is allowed
+
+```js
+export const config = {
+  runtime: `nodejs`,
+}
+```
+
 ### Useful Links
 
 - [Enabling AMP Support](https://nextjs.org/docs/advanced-features/amp-support/introduction)
 - [API Middlewares](https://nextjs.org/docs/api-routes/api-middlewares)
+- [Switchable Runtime](https://nextjs.org/docs/advanced-features/react-18/switchable-runtime)

packages/next/build/analysis/get-page-static-info.ts

@@ -243,7 +243,7 @@ function warnAboutUnsupportedValue(
   Log.warn(
     `You have exported a \`config\` field in ${
       page ? `route "${page}"` : `"${pageFilePath}"`
-    } that Next.js can't recognize, so it will be ignored`
+    } that Next.js can't recognize, so it will be ignored. See: https://nextjs.org/docs/messages/invalid-page-config`
   )
   warnedUnsupportedValueMap.set(pageFilePath, true)
 }