From f9e6ea73821b3c5c79eca20bc01f81c832a31f2c Mon Sep 17 00:00:00 2001
From: Yusuke Wada <yusuke@kamawada.com>
Date: Tue, 15 Oct 2024 11:54:31 +0900
Subject: [PATCH] fix(factory): revert PR #3498 (#3515)

---
 src/helper/factory/index.test.ts | 50 +++++++++++++++-----------------
 src/helper/factory/index.ts      | 17 ++---------
 2 files changed, 26 insertions(+), 41 deletions(-)

diff --git a/src/helper/factory/index.test.ts b/src/helper/factory/index.test.ts
index b636c8b6..f807f7cf 100644
--- a/src/helper/factory/index.test.ts
+++ b/src/helper/factory/index.test.ts
@@ -37,34 +37,30 @@ describe('createMiddleware', () => {
     expect(url.pathname).toBe('/message')
   })
 
-  describe('Relax types for Bindings and Variables', () => {
-    it('Should not throw a type error', () => {
-      type Bindings = {
-        MY_VAR_IN_BINDINGS: string
+  it('Should pass generics types to chained handlers', () => {
+    type Bindings = {
+      MY_VAR_IN_BINDINGS: string
+    }
+
+    type Variables = {
+      MY_VAR: string
+    }
+
+    const app = new Hono<{ Bindings: Bindings }>()
+
+    app.get(
+      '/',
+      createMiddleware<{ Variables: Variables }>(async (c, next) => {
+        await next()
+      }),
+      createMiddleware(async (c, next) => {
+        await next()
+      }),
+      async (c) => {
+        const v = c.get('MY_VAR')
+        expectTypeOf(v).toEqualTypeOf<string>()
       }
-
-      const app = new Hono<{ Bindings: Bindings }>()
-
-      type Variables = {
-        MY_VAR: string
-      }
-
-      const middleware = (_variable: string) =>
-        createMiddleware<{ Variables: Variables }>(async (c, next) => {
-          await next()
-        })
-
-      app.get(
-        '/',
-        createMiddleware<{ Bindings: Bindings }>(async (c, next) => {
-          const mw = middleware(c.env.MY_VAR_IN_BINDINGS)
-          await mw(c, next) // `c` does not throw an error
-        }),
-        (c) => {
-          return c.json({})
-        }
-      )
-    })
+    )
   })
 })
 
diff --git a/src/helper/factory/index.ts b/src/helper/factory/index.ts
index 9680c939..c5fe7a86 100644
--- a/src/helper/factory/index.ts
+++ b/src/helper/factory/index.ts
@@ -6,7 +6,6 @@
 /* eslint-disable @typescript-eslint/no-explicit-any */
 import { Hono } from '../../hono'
 import type { Env, H, HandlerResponse, Input, MiddlewareHandler } from '../../types'
-import type { Simplify } from '../../utils/types'
 
 type InitApp<E extends Env = Env> = (app: Hono<E>) => void
 
@@ -238,20 +237,10 @@ export const createFactory = <E extends Env = any, P extends string = any>(init?
   initApp?: InitApp<E>
 }): Factory<E, P> => new Factory<E, P>(init)
 
-// Add `any` if it's undefined to relax types
-// { Variables: Variables } => { Bindings: any, Variables: any }
-// { Bindings: Bindings } => { Bindings: Bindings, Variables: any }
-
-type AddAnyToEnv<T extends { Variables?: object; Bindings?: object }> = {
-  Bindings: undefined extends T['Bindings'] ? any : T['Bindings']
-  Variables: undefined extends T['Variables'] ? any : T['Variables']
-}
-
 export const createMiddleware = <
   E extends Env = any,
   P extends string = string,
-  I extends Input = {},
-  E2 extends Env = Simplify<AddAnyToEnv<E>>
+  I extends Input = {}
 >(
-  middleware: MiddlewareHandler<E2, P, I>
-): MiddlewareHandler<E2, P, I> => createFactory<E2, P>().createMiddleware<I>(middleware)
+  middleware: MiddlewareHandler<E, P, I>
+): MiddlewareHandler<E, P, I> => createFactory<E, P>().createMiddleware<I>(middleware)