feat: add typescript types

.github/workflows/ci.yml

@@ -38,6 +38,9 @@ jobs:
       - name: Lint code
         run: npm run lint
 
+      - name: Check types
+        run: npm run test-types
+
       - name: Upload code coverage
         uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
         with:

.gitignore

@@ -3,3 +3,4 @@ coverage/
 node_modules/
 npm-debug.log
 package-lock.json
+*.lock

index.d.ts

@@ -0,0 +1,53 @@
+import type { IncomingMessage, ServerResponse } from 'node:http'
+import type {
+  Handler,
+  NextFunction,
+  RequestHandler,
+  Route as IRoute
+} from './lib/route'
+import Route = require('./lib/route')
+
+export type RouterMethod<T> = <F extends Handler = RequestHandler>(path: Path, handler: F) => T
+
+export type Path = string | RegExp | Array<string | RegExp>
+
+interface RouterOptions {
+  caseSensitive?: boolean
+  mergeParams?: boolean
+  strict?: boolean
+}
+
+interface Router extends RequestHandler {
+  params: Record<string, any>
+  stack: any[]
+  caseSensitive: boolean
+  mergeParams: boolean
+  strict: boolean
+
+  handle(req: IncomingMessage, res: ServerResponse, callback: NextFunction): void
+  param(name: string, fn: (req: any, res: any, next: NextFunction, value: any, name: string) => void): this
+  route(path: Path): IRoute
+
+  use: {
+    <F extends Handler = RequestHandler>(path: Path, handler: F): Router
+    <F extends Handler = RequestHandler>(handler: F): Router
+  }
+
+  all: RouterMethod<this>
+  get: RouterMethod<this>
+  post: RouterMethod<this>
+  put: RouterMethod<this>
+  delete: RouterMethod<this>
+  patch: RouterMethod<this>
+  options: RouterMethod<this>
+  head: RouterMethod<this>
+}
+
+interface RouterConstructor {
+  (options?: RouterOptions): Router
+  new (options?: RouterOptions): Router
+  Route: typeof Route
+}
+
+declare const router: RouterConstructor
+export = router

lib/route.d.ts

@@ -0,0 +1,37 @@
+import type { IncomingMessage, ServerResponse } from 'node:http'
+
+export type NextFunction = (err?: any) => void
+
+export type RequestHandler = (req: IncomingMessage, res: ServerResponse, next: NextFunction) => void
+export type ErrorRequestHandler = (err: Error, req: IncomingMessage, res: ServerResponse, next: NextFunction) => void
+
+export type Handler = RequestHandler | ErrorRequestHandler
+
+export type RouteMethod<T> = <F extends Handler = RequestHandler>(handler: F) => T
+
+export interface Route {
+  path: string
+  stack: any[]
+  methods: Record<string, boolean>
+
+  _handlesMethod(method: string): boolean
+  _methods(): string[]
+  dispatch(req: IncomingMessage, res: ServerResponse, done: NextFunction): void
+
+  all: RouteMethod<this>
+  get: RouteMethod<this>
+  post: RouteMethod<this>
+  put: RouteMethod<this>
+  delete: RouteMethod<this>
+  patch: RouteMethod<this>
+  options: RouteMethod<this>
+  head: RouteMethod<this>
+}
+
+interface RouteConstructor {
+  (path: string): Route
+  new (path: string): Route
+}
+
+declare const Route: RouteConstructor
+export = Route

package.json

@@ -8,6 +8,9 @@
   ],
   "license": "MIT",
   "repository": "pillarjs/router",
+  "type": "commonjs",
+  "main": "index.js",
+  "types": "index.d.ts",
   "funding": {
     "type": "opencollective",
     "url": "https://opencollective.com/express"
@@ -20,7 +23,11 @@
     "path-to-regexp": "^8.0.0"
   },
   "devDependencies": {
+    "@arethetypeswrong/cli": "0.18.5",
+    "@tsconfig/node18": "18.2.6",
+    "@types/node": "18.19.130",
     "finalhandler": "^2.1.0",
+    "expect-type": "1.4.0",
     "mocha": "10.2.0",
     "nyc": "15.1.0",
     "run-series": "^1.1.9",
@@ -32,7 +39,8 @@
     "LICENSE",
     "HISTORY.md",
     "README.md",
-    "index.js"
+    "index.js",
+    "index.d.ts"
   ],
   "engines": {
     "node": ">= 18"
@@ -43,6 +51,7 @@
     "test:debug": "mocha --reporter spec --check-leaks test/ --inspect --inspect-brk",
     "test-ci": "nyc --reporter=lcov --reporter=text npm test",
     "test-cov": "nyc --reporter=text npm test",
-    "version": "node scripts/version-history.js && git add HISTORY.md"
+    "version": "node scripts/version-history.js && git add HISTORY.md",
+    "test-types": "tsc --noEmit && attw --pack"
   }
 }

test/types.ts

@@ -0,0 +1,25 @@
+import { IncomingMessage, ServerResponse } from "node:http";
+import { expectTypeOf } from "expect-type";
+import Router from "..";
+import { ErrorRequestHandler } from "../lib/route";
+
+const router = Router();
+
+router.get("/", function (req, res) {
+  expectTypeOf(req).toEqualTypeOf<IncomingMessage>();
+  expectTypeOf(res).toEqualTypeOf<ServerResponse>();
+});
+
+router.get("/", function (req, res, next) {
+  expectTypeOf(req).toEqualTypeOf<IncomingMessage>();
+  expectTypeOf(res).toEqualTypeOf<ServerResponse>();
+  expectTypeOf(next).toBeFunction();
+});
+
+// typescript has no way to infer the types automatically
+router.get<ErrorRequestHandler>("/", function (err, req, res, next) {
+  expectTypeOf(err).toEqualTypeOf<Error>();
+  expectTypeOf(req).toEqualTypeOf<IncomingMessage>();
+  expectTypeOf(res).toEqualTypeOf<ServerResponse>();
+  expectTypeOf(next).toBeFunction();
+});

tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "extends": "@tsconfig/node18/tsconfig.json",
+  "include": ["index.d.ts", "lib/route.d.ts", "test/types.ts"],
+  "compilerOptions": {
+    "types": ["node"]
+  }
+}