can we do this?

example/types/content.ts

@@ -0,0 +1,22 @@
+import { IRequestStrict, IRequest, RequestHandler } from 'types'
+import { IttyRouter } from 'IttyRouter'
+import { withContent } from 'withContent'
+import { HasContent } from 'types'
+
+type User = {
+  user: string
+}
+
+const router = IttyRouter()
+
+router
+  // upstream request sees the request as IRequest (default), so anything goes
+  .post<HasContent<User>>('/', withContent, ({ content }) => {
+    content.user
+  })
+
+  .get('/pollution', (request) => {
+    request.content.user
+  })
+
+export default router

example/types/middleware.ts

@@ -1,4 +1,5 @@
-import { IRequestStrict, IRequest, IttyRouter, RequestHandler } from 'IttyRouter'
+import { IRequestStrict, IRequest, RequestHandler } from 'types'
+import { IttyRouter } from 'IttyRouter'
 
 type UserRequest = {
   user: string

package.json

@@ -76,6 +76,11 @@
       "require": "./text.js",
       "types": "./text.d.ts"
     },
+    "./types": {
+      "import": "./types.mjs",
+      "require": "./types.js",
+      "types": "./types.d.ts"
+    },
     "./webp": {
       "import": "./webp.mjs",
       "require": "./webp.js",

src/IttyRouter.ts

@@ -25,7 +25,6 @@ export const IttyRouter = <
                 .replace(/\./g, '\\.')                              // dot in path
                 .replace(/(\/?)\*/g, '($1.*)?')                     // wildcard
               }/*$`),
-              // @ts-expect-error - fiddly
               handlers,                                             // embed handlers
               path,                                                 // embed clean route path
             ]

src/Router.ts

@@ -25,7 +25,6 @@ export const Router = <
                 .replace(/\./g, '\\.')                              // dot in path
                 .replace(/(\/?)\*/g, '($1.*)?')                     // wildcard
               }/*$`),
-              // @ts-expect-error - fiddly
               handlers,                                             // embed handlers
               path,                                                 // embed clean route path
             ]

src/cors.ts

@@ -1,4 +1,4 @@
-import { IRequest } from 'IttyRouter'
+import { IRequest } from './types'
 
 export type CorsOptions = {
   credentials?: true

src/createResponse.ts

@@ -1,15 +1,9 @@
-export interface ResponseFormatter {
-  (body?: any, options?: ResponseInit): Response
-}
-
-export interface BodyTransformer {
-  (body: any): string
-}
+import { ResponseFormatter } from './types'
 
  export const createResponse =
   (
     format = 'text/plain; charset=utf-8',
-    transform?: BodyTransformer
+    transform?: (body: any) => any,
   ): ResponseFormatter =>
   (body, { ...options } = {}) => {
     if (body === undefined || body instanceof Response) return body

src/error.ts

@@ -1,16 +1,5 @@
 import { json } from './json'
-
-interface ErrorLike extends Error {
-  status?: number
-  [any: string]: any
-}
-
-export type ErrorBody = string | object
-
-export interface ErrorFormatter {
-  (statusCode?: number, body?: ErrorBody): Response
-  (error: ErrorLike): Response
-}
+import { ErrorFormatter } from './types'
 
 const getMessage = (code: number): string => ({
   400: 'Bad Request',
@@ -20,7 +9,7 @@ const getMessage = (code: number): string => ({
   500: 'Internal Server Error',
 })[code] || 'Unknown Error'
 
-export const error: ErrorFormatter = (a = 500, b?: ErrorBody) => {
+export const error: ErrorFormatter = (a = 500, b?) => {
   // handle passing an Error | StatusError directly in
   if (a instanceof Error) {
     const { message, ...err } = a

src/types.ts

@@ -0,0 +1,26 @@
+// routers
+export * from './types/AutoRouterOptions'
+export * from './types/CustomRoutes'
+export * from './types/ErrorHandler'
+export * from './types/IRequest'
+export * from './types/IRequestStrict'
+export * from './types/IttyRouterOptions'
+export * from './types/IttyRouterType'
+export * from './types/RequestHandler'
+export * from './types/ResponseHandler'
+export * from './types/RequestLike'
+export * from './types/ResponseHandler'
+export * from './types/Route'
+export * from './types/RouteEntry'
+export * from './types/RouterOptions'
+export * from './types/RouterType'
+
+// withContent
+export * from './types/HasContent'
+
+// createResponse
+export * from './types/ResponseFormatter'
+
+// errors
+export * from './types/ErrorFormatter'
+

src/types/AutoRouterOptions.ts

@@ -0,0 +1,8 @@
+import { RequestHandler } from './RequestHandler'
+import { ResponseHandler } from './ResponseHandler'
+import { RouterOptions } from './RouterOptions'
+
+export type AutoRouterOptions = {
+  missing?: RequestHandler
+  format?: ResponseHandler
+} & RouterOptions

src/types/CustomRoutes.ts

@@ -0,0 +1,5 @@
+import { Route } from './Route'
+
+export type CustomRoutes<R = Route> = {
+  [key: string]: R
+}

src/types/ErrorFormatter.ts

@@ -0,0 +1,11 @@
+interface ErrorLike extends Error {
+  status?: number
+  [any: string]: any
+}
+
+type ErrorBody = string | object
+
+export interface ErrorFormatter {
+  (statusCode?: number, body?: ErrorBody): Response
+  (error: ErrorLike): Response
+}

src/types/ErrorHandler.ts

@@ -0,0 +1,4 @@
+import { IRequest } from './IRequest'
+
+export type ErrorHandler<ErrorType = Error, RequestType = IRequest, Args extends any[] = any[]> =
+    (response: ErrorType, request: RequestType, ...args: Args) => any

src/types/GenericTraps.ts

@@ -0,0 +1 @@
+export type GenericTraps = Record<string, any>

src/types/HasContent.ts

@@ -0,0 +1,5 @@
+import { IRequestStrict } from './IRequestStrict'
+
+export type HasContent<ContentType> = {
+  content: ContentType
+} & IRequestStrict

src/types/IRequest.ts

@@ -0,0 +1,4 @@
+import { GenericTraps } from './GenericTraps'
+import { IRequestStrict } from './IRequestStrict'
+
+export type IRequest = IRequestStrict & GenericTraps

src/types/IRequestStrict.ts

@@ -0,0 +1,12 @@
+export type IRequestStrict = {
+  method: string
+  url: string
+  route: string
+  params: {
+    [key: string]: string
+  }
+  query: {
+    [key: string]: string | string[] | undefined
+  }
+  proxy?: any
+} & Request

src/types/IttyRouterOptions.ts

@@ -0,0 +1,6 @@
+import { RouteEntry } from './RouteEntry'
+
+export type IttyRouterOptions = {
+  base?: string
+  routes?: RouteEntry[]
+} & Record<string, any>

src/types/IttyRouterType.ts

@@ -0,0 +1,19 @@
+import { CustomRoutes } from './CustomRoutes'
+import { IRequest } from './IRequest'
+import { RequestLike } from './RequestLike'
+import { Route } from './Route'
+import { RouteEntry } from './RouteEntry'
+
+export type IttyRouterType<R = IRequest, A extends any[] = any[], Output = any> = {
+  __proto__: IttyRouterType<R>
+  routes: RouteEntry[]
+  fetch: <Args extends any[] = A>(request: RequestLike, ...extra: Args) => Promise<Output>
+  all: Route<R, A>
+  delete: Route<R, A>
+  get: Route<R, A>
+  head: Route<R, A>
+  options: Route<R, A>
+  patch: Route<R, A>
+  post: Route<R, A>
+  put: Route<R, A>
+} & CustomRoutes<Route<R, A>>

src/types/RequestHandler.ts

@@ -0,0 +1,4 @@
+import { IRequest } from './IRequest'
+
+export type RequestHandler<R = IRequest, Args extends Array<any> = any[]> =
+  (request: R, ...args: Args) => any

src/types/RequestLike.ts

@@ -0,0 +1,6 @@
+import { GenericTraps } from './GenericTraps'
+
+export type RequestLike = {
+  method: string
+  url: string
+} & GenericTraps

src/types/ResponseFormatter.ts

@@ -0,0 +1,3 @@
+export interface ResponseFormatter {
+  (body?: any, options?: ResponseInit): Response
+}

src/types/ResponseHandler.ts

@@ -0,0 +1,4 @@
+import { IRequest } from './IRequest'
+
+export type ResponseHandler<ResponseType = Response, RequestType = IRequest, Args extends any[] = any[]> =
+    (response: ResponseType & any, request: RequestType & any, ...args: Args) => any

src/types/Route.ts

@@ -0,0 +1,8 @@
+import { IRequest } from './IRequest'
+import { IttyRouterType } from './IttyRouterType'
+import { RequestHandler } from './RequestHandler'
+
+export type Route<R = IRequest, A extends Array<any> = any[]> = <RequestType = R, Args extends Array<any> = A>(
+  path: string,
+  ...handlers: RequestHandler<RequestType, Args>[]
+) => IttyRouterType<RequestType, Args>

src/types/RouteEntry.ts

@@ -0,0 +1,8 @@
+import { RequestHandler } from './RequestHandler'
+
+export type RouteEntry = [
+  httpMethod: string,
+  match: RegExp,
+  handlers: RequestHandler[],
+  path?: string,
+]

src/types/RouterOptions.ts

@@ -0,0 +1,10 @@
+import { ErrorHandler } from './ErrorHandler'
+import { IttyRouterOptions } from './IttyRouterOptions'
+import { RequestHandler } from './RequestHandler'
+import { ResponseHandler } from './ResponseHandler'
+
+export type RouterOptions = {
+  before?: RequestHandler<any>[]
+  catch?: ErrorHandler
+  finally?: ResponseHandler[]
+} & IttyRouterOptions

src/types/RouterType.ts

@@ -0,0 +1,11 @@
+import { ErrorHandler } from './ErrorHandler'
+import { IRequest } from './IRequest'
+import { IttyRouterType } from './IttyRouterType'
+import { RequestHandler } from './RequestHandler'
+import { ResponseHandler } from './ResponseHandler'
+
+export type RouterType<R = IRequest, Args extends any[] = any[]> = {
+  before?: RequestHandler<any>[]
+  catch?: ErrorHandler
+  finally?: ResponseHandler[]
+} & IttyRouterType<R, Args>

src/withContent.ts

@@ -1,8 +1,4 @@
-import { IRequest, IRequestStrict } from './IttyRouter'
-
-export type HasContent<ContentType> = {
-  content: ContentType
-} & IRequestStrict
+import { IRequest } from './types'
 
 // withContent - embeds any request body as request.content
 export const withContent = async (request: IRequest): Promise<void> => {

src/withCookies.ts

@@ -1,4 +1,4 @@
-import { IRequest } from './IttyRouter'
+import { IRequest } from './types'
 
 type KVPair = [string, string?]
 

src/withParams.ts

@@ -1,4 +1,4 @@
-import { IRequest } from './IttyRouter'
+import { IRequest } from './types'
 
 export const withParams = (request: IRequest): void => {
   request.proxy = new Proxy(request.proxy || request, {

vitest.config.ts

@@ -10,7 +10,8 @@ export default defineConfig({
         '**/example/**',
         '**/lib/**',
         'src/index.ts',
-        'src/types.d.ts',
+        'src/types',
+        'src/types.ts',
         'src/websocket.ts',
       ],
     },