Fix Utility Types (vercel#11077)

packages/next/build/plugins/collect-plugins.ts

@@ -134,11 +134,6 @@ async function collectPluginMeta(
   }
 }
 
-type SeparatedPlugins = {
-  appMiddlewarePlugins: PluginMetaData[]
-  documentMiddlewarePlugins: PluginMetaData[]
-}
-
 // clean package name so it can be used as variable
 export const getPluginId = (pkg: string): string => {
   pkg = pkg.replace(/\W/g, '')
@@ -254,6 +249,4 @@ async function _collectPlugins(
 
 // only execute it once between server/client configs
 // since the plugins need to match
-export const collectPlugins = execOnce(
-  _collectPlugins
-) as typeof _collectPlugins
+export const collectPlugins = execOnce(_collectPlugins)

packages/next/next-server/lib/utils.ts

@@ -239,17 +239,19 @@ export type NextApiHandler<T = any> = (
 /**
  * Utils
  */
-export function execOnce(this: any, fn: (...args: any) => any) {
+export function execOnce<T extends (...args: any[]) => ReturnType<T>>(
+  fn: T
+): T {
   let used = false
-  let result: any = null
+  let result: ReturnType<T>
 
-  return (...args: any) => {
+  return ((...args: any[]) => {
     if (!used) {
       used = true
-      result = fn.apply(this, args)
+      result = fn(...args)
     }
     return result
-  }
+  }) as T
 }
 
 export function getLocationOrigin() {
@@ -263,7 +265,7 @@ export function getURL() {
   return href.substring(origin.length)
 }
 
-export function getDisplayName(Component: ComponentType<any>) {
+export function getDisplayName<P>(Component: ComponentType<P>) {
   return typeof Component === 'string'
     ? Component
     : Component.displayName || Component.name || 'Unknown'
@@ -296,7 +298,7 @@ export async function loadGetInitialProps<
         pageProps: await loadGetInitialProps(ctx.Component, ctx.ctx),
       }
     }
-    return {} as any
+    return {} as IP
   }
 
   const props = await App.getInitialProps(ctx)
@@ -356,7 +358,7 @@ export function formatWithValidation(
     }
   }
 
-  return format(url as any, options)
+  return format(url as URL, options)
 }
 
 export const SP = typeof performance !== 'undefined'