fix: reduce Context code

src/context.test.ts

@@ -172,6 +172,29 @@ describe('Context', () => {
     expect(foo).toBe('Bar, Buzz')
   })
 
+  it('c.body() - content-type cannot be overridden by the default response when append headers', async () => {
+    c.header('Vary', 'Accept-Encoding', { append: true })
+    c.res
+    c.header('Content-Type', 'text/html')
+    const res = c.body('<h1>Hi</h1>')
+    expect(res.headers.get('Content-Type')).toMatch('text/html')
+  })
+
+  it('c.body() - content-type can set explicitly via c.res.headers', async () => {
+    c.header('Vary', 'Accept-Encoding', { append: true })
+    c.res.headers.set('Content-Type', 'text/html')
+    const res = c.body('<h1>Hi</h1>')
+    expect(res.headers.get('Content-Type')).toMatch('text/html')
+  })
+
+  it('c.body() - Different header settings require ensuring order', async () => {
+    c.header('Vary', 'Accept-Encoding', { append: true })
+    c.header('Content-Type', 'image/png')
+    c.res.headers.set('Content-Type', 'text/html')
+    const res = c.body('<h1>Hi</h1>')
+    expect(res.headers.get('Content-Type')).toMatch('text/html')
+  })
+
   it('c.status()', async () => {
     c.status(201)
     const res = c.body('Hi')
@@ -418,6 +441,22 @@ describe('Context header', () => {
     c.header('X-Custom', 'Message')
     expect(c.res.headers.get('X-Custom')).toBe('Message')
   })
+
+  it('Should handle headers with array values correctly', async () => {
+    c.header('X-Array', 'value1')
+    const res = c.json({ test: 'data' }, 200, {
+      'X-Array': ['new1', 'new2'],
+    })
+    expect(res.headers.get('X-Array')).toBe('new1, new2')
+  })
+
+  it('Should remove existing header when new value is empty array', async () => {
+    c.header('X-Test', 'existing')
+    const res = c.json({ test: 'data' }, 200, {
+      'X-Test': [],
+    })
+    expect(res.headers.get('X-Test')).toBeNull()
+  })
 })
 
 describe('Pass a ResponseInit to respond methods', () => {

src/context.ts

@@ -273,18 +273,11 @@ type ResponseOrInit<T extends StatusCode = StatusCode> = ResponseInit<T> | Respo
 
 export const TEXT_PLAIN = 'text/plain; charset=UTF-8'
 
-/**
- * Sets the headers of a response.
- *
- * @param headers - The Headers object to set the headers on.
- * @param map - A record of header key-value pairs to set.
- * @returns The updated Headers object.
- */
-const setHeaders = (headers: Headers, map: Record<string, string> = {}) => {
-  for (const key of Object.keys(map)) {
-    headers.set(key, map[key])
+const setDefaultContentType = (contentType: string, headers?: HeaderRecord): HeaderRecord => {
+  return {
+    'Content-Type': contentType,
+    ...headers,
   }
-  return headers
 }
 
 export class Context<
@@ -329,15 +322,13 @@ export class Context<
    */
   error: Error | undefined
 
-  #status: StatusCode = 200
+  #status: StatusCode | undefined
   #executionCtx: FetchEventLike | ExecutionContext | undefined
-  #headers: Headers | undefined
-  #preparedHeaders: Record<string, string> | undefined
   #res: Response | undefined
-  #isFresh = true
   #layout: Layout<PropsForRenderer & { Layout: Layout }> | undefined
   #renderer: Renderer | undefined
   #notFoundHandler: NotFoundHandler<E> | undefined
+  #preparedHeaders: Headers | undefined
 
   #matchResult: Result<[H, RouterRoute]> | undefined
   #path: string | undefined
@@ -400,8 +391,9 @@ export class Context<
    * The Response object for the current request.
    */
   get res(): Response {
-    this.#isFresh = false
-    return (this.#res ||= new Response('404 Not Found', { status: 404 }))
+    return (this.#res ||= new Response(null, {
+      headers: (this.#preparedHeaders ??= new Headers()),
+    }))
   }
 
   /**
@@ -410,7 +402,6 @@ export class Context<
    * @param _res - The Response object to set.
    */
   set res(_res: Response | undefined) {
-    this.#isFresh = false
     if (this.#res && _res) {
       _res = new Response(_res.body, _res)
       for (const [k, v] of this.#res.headers.entries()) {
@@ -515,46 +506,17 @@ export class Context<
     if (this.finalized) {
       this.#res = new Response((this.#res as Response).body, this.#res)
     }
-    // Clear the header
+    const headers = this.#res ? this.#res.headers : (this.#preparedHeaders ??= new Headers())
     if (value === undefined) {
-      if (this.#headers) {
-        this.#headers.delete(name)
-      } else if (this.#preparedHeaders) {
-        delete this.#preparedHeaders[name.toLocaleLowerCase()]
-      }
-      if (this.finalized) {
-        this.res.headers.delete(name)
-      }
-      return
-    }
-
-    if (options?.append) {
-      if (!this.#headers) {
-        this.#isFresh = false
-        this.#headers = new Headers(this.#preparedHeaders)
-        this.#preparedHeaders = {}
-      }
-      this.#headers.append(name, value)
+      headers.delete(name)
+    } else if (options?.append) {
+      headers.append(name, value)
     } else {
-      if (this.#headers) {
-        this.#headers.set(name, value)
-      } else {
-        this.#preparedHeaders ??= {}
-        this.#preparedHeaders[name.toLowerCase()] = value
-      }
-    }
-
-    if (this.finalized) {
-      if (options?.append) {
-        this.res.headers.append(name, value)
-      } else {
-        this.res.headers.set(name, value)
-      }
+      headers.set(name, value)
     }
   }
 
   status = (status: StatusCode): void => {
-    this.#isFresh = false
     this.#status = status
   }
 
@@ -634,65 +596,36 @@ export class Context<
     arg?: StatusCode | ResponseOrInit,
     headers?: HeaderRecord
   ): Response {
-    // Optimized
-    if (this.#isFresh && !headers && !arg && this.#status === 200) {
-      return new Response(data, {
-        headers: this.#preparedHeaders,
-      })
-    }
-
-    if (arg && typeof arg !== 'number') {
-      const header = new Headers(arg.headers)
-      if (this.#headers) {
-        // If the header is set by c.header() and arg.headers, c.header() will be prioritized.
-        this.#headers.forEach((v, k) => {
-          if (k === 'set-cookie') {
-            header.append(k, v)
-          } else {
-            header.set(k, v)
-          }
-        })
-      }
-      const headers = setHeaders(header, this.#preparedHeaders)
-      return new Response(data, {
-        headers,
-        status: arg.status ?? this.#status,
-      })
-    }
-
-    const status = typeof arg === 'number' ? arg : this.#status
-    this.#preparedHeaders ??= {}
-
-    this.#headers ??= new Headers()
-    setHeaders(this.#headers, this.#preparedHeaders)
-
-    if (this.#res) {
-      this.#res.headers.forEach((v, k) => {
-        if (k === 'set-cookie') {
-          this.#headers?.append(k, v)
+    const responseHeaders = this.#res
+      ? new Headers(this.#res.headers)
+      : this.#preparedHeaders ?? new Headers()
+
+    if (typeof arg === 'object' && 'headers' in arg) {
+      const argHeaders = arg.headers instanceof Headers ? arg.headers : new Headers(arg.headers)
+      for (const [key, value] of argHeaders) {
+        if (key.toLowerCase() === 'set-cookie') {
+          responseHeaders.append(key, value)
         } else {
-          this.#headers?.set(k, v)
+          responseHeaders.set(key, value)
         }
-      })
-      setHeaders(this.#headers, this.#preparedHeaders)
+      }
     }
 
-    headers ??= {}
-    for (const [k, v] of Object.entries(headers)) {
-      if (typeof v === 'string') {
-        this.#headers.set(k, v)
-      } else {
-        this.#headers.delete(k)
-        for (const v2 of v) {
-          this.#headers.append(k, v2)
+    if (headers) {
+      for (const [k, v] of Object.entries(headers)) {
+        if (typeof v === 'string') {
+          responseHeaders.set(k, v)
+        } else {
+          responseHeaders.delete(k)
+          for (const v2 of v) {
+            responseHeaders.append(k, v2)
+          }
         }
       }
     }
 
-    return new Response(data, {
-      status,
-      headers: this.#headers,
-    })
+    const status = typeof arg === 'number' ? arg : arg?.status ?? this.#status
+    return new Response(data, { status, headers: responseHeaders })
   }
 
   newResponse: NewResponse = (...args) => this.#newResponse(...(args as Parameters<NewResponse>))
@@ -722,11 +655,7 @@ export class Context<
     data: Data | null,
     arg?: StatusCode | RequestInit,
     headers?: HeaderRecord
-  ): ReturnType<BodyRespond> => {
-    return (
-      typeof arg === 'number' ? this.#newResponse(data, arg, headers) : this.#newResponse(data, arg)
-    ) as ReturnType<BodyRespond>
-  }
+  ): ReturnType<BodyRespond> => this.#newResponse(data, arg, headers) as ReturnType<BodyRespond>
 
   /**
    * `.text()` can render text as `Content-Type:text/plain`.
@@ -745,22 +674,13 @@ export class Context<
     arg?: ContentfulStatusCode | ResponseOrInit,
     headers?: HeaderRecord
   ): ReturnType<TextRespond> => {
-    // If the header is empty, return Response immediately.
-    // Content-Type will be added automatically as `text/plain`.
-    if (!this.#preparedHeaders) {
-      if (this.#isFresh && !headers && !arg) {
-        // @ts-expect-error `Response` due to missing some types-only keys
-        return new Response(text)
-      }
-      this.#preparedHeaders = {}
-    }
-    this.#preparedHeaders['content-type'] = TEXT_PLAIN
-    if (typeof arg === 'number') {
-      // @ts-expect-error `Response` due to missing some types-only keys
-      return this.#newResponse(text, arg, headers)
-    }
-    // @ts-expect-error `Response` due to missing some types-only keys
-    return this.#newResponse(text, arg)
+    return !this.#preparedHeaders && !this.#status && !arg && !headers && !this.finalized
+      ? (new Response(text) as ReturnType<TextRespond>)
+      : (this.#newResponse(
+          text,
+          arg,
+          setDefaultContentType(TEXT_PLAIN, headers)
+        ) as ReturnType<TextRespond>)
   }
 
   /**
@@ -783,34 +703,23 @@ export class Context<
     arg?: U | ResponseOrInit<U>,
     headers?: HeaderRecord
   ): JSONRespondReturn<T, U> => {
-    const body = JSON.stringify(object)
-    this.#preparedHeaders ??= {}
-    this.#preparedHeaders['content-type'] = 'application/json'
-    /* eslint-disable @typescript-eslint/no-explicit-any */
-    return (
-      typeof arg === 'number' ? this.#newResponse(body, arg, headers) : this.#newResponse(body, arg)
-    ) as any
+    return this.#newResponse(
+      JSON.stringify(object),
+      arg,
+      setDefaultContentType('application/json', headers)
+    ) /* eslint-disable @typescript-eslint/no-explicit-any */ as any
   }
 
   html: HTMLRespond = (
     html: string | Promise<string>,
     arg?: ContentfulStatusCode | ResponseOrInit<ContentfulStatusCode>,
     headers?: HeaderRecord
   ): Response | Promise<Response> => {
-    this.#preparedHeaders ??= {}
-    this.#preparedHeaders['content-type'] = 'text/html; charset=UTF-8'
-
-    if (typeof html === 'object') {
-      return resolveCallback(html, HtmlEscapedCallbackPhase.Stringify, false, {}).then((html) => {
-        return typeof arg === 'number'
-          ? this.#newResponse(html, arg, headers)
-          : this.#newResponse(html, arg)
-      })
-    }
-
-    return typeof arg === 'number'
-      ? this.#newResponse(html as string, arg, headers)
-      : this.#newResponse(html as string, arg)
+    const res = (html: string) =>
+      this.#newResponse(html, arg, setDefaultContentType('text/html; charset=UTF-8', headers))
+    return typeof html === 'object'
+      ? resolveCallback(html, HtmlEscapedCallbackPhase.Stringify, false, {}).then(res)
+      : res(html)
   }
 
   /**
@@ -832,8 +741,7 @@ export class Context<
     location: string | URL,
     status?: T
   ): Response & TypedResponse<undefined, T, 'redirect'> => {
-    this.#headers ??= new Headers()
-    this.#headers.set('Location', String(location))
+    this.header('Location', String(location))
     return this.newResponse(null, status ?? 302) as any
   }