chore(next): export/lib/next-server missing types (#13320)

packages/next/export/index.ts

@@ -90,7 +90,7 @@ export default async function (
   options: any,
   configuration?: any
 ): Promise<void> {
-  function log(message: string) {
+  function log(message: string): void {
     if (options.silent) {
       return
     }

packages/next/lib/recursive-copy.ts

@@ -23,7 +23,7 @@ export async function recursiveCopy(
 
   const sema = new Sema(concurrency)
 
-  async function _copy(item: string) {
+  async function _copy(item: string): Promise<void> {
     const target = item.replace(from, to)
     const stats = await promises.stat(item)
 

packages/next/lib/verifyTypeScriptSetup.ts

@@ -30,7 +30,7 @@ async function checkDependencies({
 }: {
   dir: string
   isYarn: boolean
-}) {
+}): Promise<string> {
   const requiredPackages = [
     { file: 'typescript', pkg: 'typescript' },
     { file: '@types/react/index.d.ts', pkg: '@types/react' },

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

@@ -5,11 +5,11 @@ export function isInAmpMode({
   ampFirst = false,
   hybrid = false,
   hasQuery = false,
-} = {}) {
+} = {}): boolean {
   return ampFirst || (hybrid && hasQuery)
 }
 
-export function useAmp() {
+export function useAmp(): boolean {
   // Don't assign the context value to a variable to save bytes
   return isInAmpMode(React.useContext(AmpStateContext))
 }

packages/next/next-server/lib/dynamic.tsx

@@ -52,7 +52,7 @@ export type LoadableComponent<P = {}> = React.ComponentType<P>
 export function noSSR<P = {}>(
   LoadableInitializer: LoadableFn<P>,
   loadableOptions: LoadableOptions<P>
-) {
+): React.ComponentType<P> {
   // Removing webpack and modules means react-loadable won't try preloading
   delete loadableOptions.webpack
   delete loadableOptions.modules

packages/next/next-server/lib/head.tsx

@@ -8,7 +8,7 @@ type WithInAmpMode = {
   inAmpMode?: boolean
 }
 
-export function defaultHead(inAmpMode = false) {
+export function defaultHead(inAmpMode = false): JSX.Element[] {
   const head = [<meta charSet="utf-8" />]
   if (!inAmpMode) {
     head.push(<meta name="viewport" content="width=device-width" />)

packages/next/next-server/lib/runtime-config.ts

@@ -4,6 +4,6 @@ export default () => {
   return runtimeConfig
 }
 
-export function setConfig(configValue: any) {
+export function setConfig(configValue: any): void {
   runtimeConfig = configValue
 }

packages/next/next-server/lib/side-effect.tsx

@@ -17,7 +17,7 @@ export default () => {
   const mountedInstances: Set<any> = new Set()
   let state: State
 
-  function emitChange(component: React.Component<SideEffectProps>) {
+  function emitChange(component: React.Component<SideEffectProps>): void {
     state = component.props.reduceComponentsToState(
       [...mountedInstances],
       component.props

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

@@ -347,7 +347,7 @@ export const urlObjectKeys = [
 export function formatWithValidation(
   url: UrlObject,
   options?: URLFormatOptions
-) {
+): string {
   if (process.env.NODE_ENV === 'development') {
     if (url !== null && typeof url === 'object') {
       Object.keys(url).forEach((key) => {