From db53184e1d67a0b6428e812af4e42106f5b0693f Mon Sep 17 00:00:00 2001
From: Hunter Tunnicliff <hunter@tunnicliff.co>
Date: Sat, 16 Jul 2022 08:38:09 -0700
Subject: [PATCH] Remove `ExpressMiddleware`

---
 EXAMPLES.md  |  6 ++---
 README.md    | 64 +++++++++++-----------------------------------------
 lib/types.ts | 33 +++++++++++----------------
 3 files changed, 29 insertions(+), 74 deletions(-)

diff --git a/EXAMPLES.md b/EXAMPLES.md
index d489175..d7fa6b2 100644
--- a/EXAMPLES.md
+++ b/EXAMPLES.md
@@ -5,9 +5,9 @@
 Middleware that does work before a request:
 
 ```ts
-import type { NextMiddleware } from "next-api-middleware";
+import type { Middleware } from "next-api-middleware";
 
-export const addRequestUUID: NextMiddleware = async (req, res, next) => {
+export const addRequestUUID: Middleware = async (req, res, next) => {
   // Set a custom header
   res.setHeader("X-Response-ID", uuid());
 
@@ -34,7 +34,7 @@ export const addRequestTiming = async (req, res, next) => {
 Middleware that catches errors that occur in remaining middleware _and_ the request:
 
 ```ts
-export const logErrorsWithACME: NextMiddleware = async (req, res, next) => {
+export const logErrorsWithACME: Middleware = async (req, res, next) => {
   try {
     // Catch any errors that are thrown in remaining
     // middleware and the API route handler
diff --git a/README.md b/README.md
index 9e803c5..277a29f 100644
--- a/README.md
+++ b/README.md
@@ -36,20 +36,18 @@ This library attempts to provide minimal, clean, composable middleware patterns
 - [Advanced](#advanced)
   - [Debugging](#debugging)
   - [Middleware Factories](#middleware-factories)
-  - [Middleware Types](#middleware-types)
-    - [`NextMiddleware`](#nextmiddleware-preferred)
-    - [`ExpressMiddleware`](#expressmiddleware-compatibility)
+  - [Middleware Signature](#middleware-types)
 
 ## Quick Start
 
 ```ts
-import { label, NextMiddleware } from "next-api-middleware";
+import { label, Middleware } from "next-api-middleware";
 import * as Sentry from "@sentry/nextjs";
 import nanoid from "nanoid";
 
 // 1 – Create middleware functions
 
-const captureErrors: NextMiddleware = async (req, res, next) => {
+const captureErrors: Middleware = async (req, res, next) => {
   try {
     // Catch any errors that are thrown in remaining
     // middleware and the API route handler
@@ -62,7 +60,7 @@ const captureErrors: NextMiddleware = async (req, res, next) => {
   }
 };
 
-const addRequestId: NextMiddleware = async (req, res, next) => {
+const addRequestId: Middleware = async (req, res, next) => {
   // Let remaining middleware and API route execute
   await next();
 
@@ -293,11 +291,11 @@ Since `use` and `label` accept values that evaluate to middleware functions, thi
 Here's an example of a factory that generates a middleware function to only allow requests with a given HTTP method:
 
 ```ts
-import { NextMiddleware } from "next-api-middleware";
+import { Middleware } from "next-api-middleware";
 
 const httpMethod = (
   allowedHttpMethod: "GET" | "POST" | "PATCH"
-): NextMiddleware => {
+): Middleware => {
   return async function (req, res, next) {
     if (req.method === allowedHttpMethod || req.method == "OPTIONS") {
       await next();
@@ -311,50 +309,14 @@ const httpMethod = (
 export const postRequestsOnlyMiddleware = httpMethod("POST");
 ```
 
-### Middleware Types
+### Middleware Signature
 
-`next-api-middleware` supports two middleware signatures, `NextMiddleware` and `ExpressMiddleware`.
-
-#### `NextMiddleware`
-
-`NextMiddleware` is inspired by the asyncronous middleware style popularized by Koa.js. Prefer this style when writing your own middleware.
+`Middleware` is inspired by the asyncronous middleware style popularized by Koa.js.
 
 ```ts
-interface NextMiddleware {
-  (
-    req: NextApiRequest,
-    res: NextApiResponse,
-    next: () => Promise<void>
-  ): Promise<void>;
-}
-```
-
-#### `ExpressMiddleware` (compatibility)
-
-`ExpressMiddleware` roughly matches the signature used by Express/Connect style middleware. This type can be used when importing third-party libraries such as `cors`.
-
-```ts
-interface ExpressMiddleware<
-  Request = IncomingMessage,
-  Response = ServerResponse
-> {
-  (
-    req: Request,
-    res: Response,
-    next: (error?: any) => void | Promise<void>
-  ): void;
-}
-```
-
-An example using `cors`:
-
-```ts
-import { use } from "next-api-middleware";
-import cors from "cors";
-
-export const withMiddleware = use(
-  // Asserting express/connect middleware as an `ExpressMiddleware` interface
-  // can resolve type conflicts by libraries that provide their own types.
-  cors() as ExpressMiddleware
-);
+type Middleware<Request = NextApiRequest, Response = NextApiResponse> = (
+  req: Request,
+  res: Response,
+  next: () => Promise<void>
+) => Promise<void>;
 ```
diff --git a/lib/types.ts b/lib/types.ts
index 082e472..fd355ed 100644
--- a/lib/types.ts
+++ b/lib/types.ts
@@ -1,23 +1,16 @@
 import type { NextApiRequest, NextApiResponse } from "next";
 
-export interface NextMiddleware {
-  (
-    req: NextApiRequest,
-    res: NextApiResponse,
-    next: () => Promise<void>
-  ): Promise<void>;
-}
+export type Middleware<Request = NextApiRequest, Response = NextApiResponse> = (
+  req: Request,
+  res: Response,
+  next: () => Promise<void>
+) => Promise<void>;
 
-export interface ExpressMiddleware<Request = any, Response = any> {
-  (
-    req: Request,
-    res: Response,
-    next: (error?: any) => void | Promise<void>
-  ): void;
-}
-
-export type Middleware = NextMiddleware | ExpressMiddleware;
-
-export interface LabeledMiddleware {
-  [name: string]: Middleware | Middleware[];
-}
+export type LabeledMiddleware<
+  Request = NextApiRequest,
+  Response = NextApiResponse
+> = {
+  [name: string]:
+    | Middleware<Request, Response>
+    | Array<Middleware<Request, Response>>;
+};