From efc8a461c0ed9164e7811cb40b593c7eec6f313e Mon Sep 17 00:00:00 2001
From: Yusuke Wada <yusuke@kamawada.com>
Date: Sat, 28 Dec 2024 11:04:20 +0900
Subject: [PATCH] feat(context): `ResponseInit` accepts generics `StatusCode`
 for `status` (#3770)

---
 src/context.ts    | 30 +++++++++++++++++-------------
 src/types.test.ts | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 13 deletions(-)

diff --git a/src/context.ts b/src/context.ts
index c5aa68e77..0c86d3dd8 100644
--- a/src/context.ts
+++ b/src/context.ts
@@ -108,7 +108,7 @@ interface Set<E extends Env> {
  */
 interface NewResponse {
   (data: Data | null, status?: StatusCode, headers?: HeaderRecord): Response
-  (data: Data | null, init?: ResponseInit): Response
+  (data: Data | null, init?: ResponseOrInit): Response
 }
 
 /**
@@ -118,7 +118,8 @@ interface BodyRespond {
   // if we return content, only allow the status codes that allow for returning the body
   (data: Data, status?: ContentfulStatusCode, headers?: HeaderRecord): Response
   (data: null, status?: StatusCode, headers?: HeaderRecord): Response
-  (data: Data | null, init?: ResponseInit): Response
+  (data: Data, init?: ResponseOrInit<ContentfulStatusCode>): Response
+  (data: null, init?: ResponseOrInit): Response
 }
 
 /**
@@ -142,7 +143,7 @@ interface TextRespond {
   ): Response & TypedResponse<T, U, 'text'>
   <T extends string, U extends ContentfulStatusCode = ContentfulStatusCode>(
     text: T,
-    init?: ResponseInit
+    init?: ResponseOrInit<U>
   ): Response & TypedResponse<T, U, 'text'>
 }
 
@@ -173,7 +174,7 @@ interface JSONRespond {
     U extends ContentfulStatusCode = ContentfulStatusCode
   >(
     object: T,
-    init?: ResponseInit
+    init?: ResponseOrInit<U>
   ): JSONRespondReturn<T, U>
 }
 
@@ -213,9 +214,10 @@ interface HTMLRespond {
     status?: ContentfulStatusCode,
     headers?: HeaderRecord
   ): T extends string ? Response : Promise<Response>
-  <T extends string | Promise<string>>(html: T, init?: ResponseInit): T extends string
-    ? Response
-    : Promise<Response>
+  <T extends string | Promise<string>>(
+    html: T,
+    init?: ResponseOrInit<ContentfulStatusCode>
+  ): T extends string ? Response : Promise<Response>
 }
 
 /**
@@ -257,12 +259,14 @@ type ResponseHeadersInit =
   | Record<string, string>
   | Headers
 
-interface ResponseInit {
+interface ResponseInit<T extends StatusCode = StatusCode> {
   headers?: ResponseHeadersInit
-  status?: number
+  status?: T
   statusText?: string
 }
 
+type ResponseOrInit<T extends StatusCode = StatusCode> = ResponseInit<T> | Response
+
 export const TEXT_PLAIN = 'text/plain; charset=UTF-8'
 
 /**
@@ -632,7 +636,7 @@ export class Context<
 
   #newResponse(
     data: Data | null,
-    arg?: StatusCode | ResponseInit,
+    arg?: StatusCode | ResponseOrInit,
     headers?: HeaderRecord
   ): Response {
     // Optimized
@@ -739,7 +743,7 @@ export class Context<
    */
   text: TextRespond = (
     text: string,
-    arg?: ContentfulStatusCode | ResponseInit,
+    arg?: ContentfulStatusCode | ResponseOrInit,
     headers?: HeaderRecord
   ): ReturnType<TextRespond> => {
     // If the header is empty, return Response immediately.
@@ -777,7 +781,7 @@ export class Context<
     U extends ContentfulStatusCode = ContentfulStatusCode
   >(
     object: T,
-    arg?: U | ResponseInit,
+    arg?: U | ResponseOrInit<U>,
     headers?: HeaderRecord
   ): JSONRespondReturn<T, U> => {
     const body = JSON.stringify(object)
@@ -791,7 +795,7 @@ export class Context<
 
   html: HTMLRespond = (
     html: string | Promise<string>,
-    arg?: ContentfulStatusCode | ResponseInit,
+    arg?: ContentfulStatusCode | ResponseOrInit<ContentfulStatusCode>,
     headers?: HeaderRecord
   ): Response | Promise<Response> => {
     this.#preparedHeaders ??= {}
diff --git a/src/types.test.ts b/src/types.test.ts
index 5118d3212..bad8ab2ca 100644
--- a/src/types.test.ts
+++ b/src/types.test.ts
@@ -2247,6 +2247,7 @@ describe('Returning type from `app.use(path, mw)`', () => {
     type verify = Expect<Equal<Expected, Actual>>
   })
 })
+
 describe('generic typed variables', () => {
   const okHelper = (c: Context) => {
     return <TData>(data: TData) => c.json({ data })
@@ -2271,6 +2272,7 @@ describe('generic typed variables', () => {
     expectTypeOf<Actual>().toEqualTypeOf<Expected>()
   })
 })
+
 describe('status code', () => {
   const app = new Hono()
 
@@ -2279,14 +2281,51 @@ describe('status code', () => {
     type Actual = ExtractSchema<typeof route>['/']['$get']['status']
     expectTypeOf<Actual>().toEqualTypeOf<ContentfulStatusCode>()
   })
+
   it('should only allow to return .body(null) with all status codes', async () => {
     const route = app.get('/', async (c) => c.body(null))
     type Actual = ExtractSchema<typeof route>['/']['$get']['status']
     expectTypeOf<Actual>().toEqualTypeOf<StatusCode>()
   })
+
   it('should only allow to return .text() with contentful status codes', async () => {
     const route = app.get('/', async (c) => c.text('whatever'))
     type Actual = ExtractSchema<typeof route>['/']['$get']['status']
     expectTypeOf<Actual>().toEqualTypeOf<ContentfulStatusCode>()
   })
+
+  it('should throw type error when .json({}) is used with contentless status codes', async () => {
+    // @ts-expect-error 204 is not contentful status code
+    app.get('/', async (c) => c.json({}, 204))
+    app.get('/', async (c) =>
+      c.json(
+        {},
+        // @ts-expect-error 204 is not contentful status code
+        {
+          status: 204,
+        }
+      )
+    )
+  })
+
+  it('should throw type error when .body(content) is used with contentless status codes', async () => {
+    // @ts-expect-error 204 is not contentful status code
+    app.get('/', async (c) => c.body('content', 204))
+    // @ts-expect-error 204 is not contentful status code
+    app.get('/', async (c) => c.body('content', { status: 204 }))
+  })
+
+  it('should throw type error when .text(content) is used with contentless status codes', async () => {
+    // @ts-expect-error 204 is not contentful status code
+    app.get('/', async (c) => c.text('content', 204))
+    // @ts-expect-error 204 is not contentful status code
+    app.get('/', async (c) => c.text('content', { status: 204 }))
+  })
+
+  it('should throw type error when .html(content) is used with contentless status codes', async () => {
+    // @ts-expect-error 204 is not contentful status code
+    app.get('/', async (c) => c.html('<h1>title</h1>', 204))
+    // @ts-expect-error 204 is not contentful status code
+    app.get('/', async (c) => c.html('<h1>title</h1>', { status: 204 }))
+  })
 })