perf(hono-base): don't import HTTPException

[yusukebe]

This is like a refactor but is made a perf since reducing the bundle size for the performance.

With this PR, the hono-base.ts does not need to import the HTTPException class directly. So, the bundle size for the app that does not use HTTPException will be small. To enable it, it does not use instanceOf; it will detect by checking the property named a symbol of IS_HTTP_EXCEPTION.

Result:

It was reduced by 260 bytes. It seems small, but reducing size is important for edge environments such as Cloudflare Workers.

The author should do the following, if applicable

• Add tests
• Run tests
• bun run format:fix && bun run lint:fix to format the code
• Add TSDoc/JSDoc to document the code

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.88%. Comparing base (320b945) to head (afb729e).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2885   +/-   ##
=======================================
  Coverage   87.88%   87.88%           
=======================================
  Files         139      139           
  Lines       14208    14215    +7     
  Branches     2314     2338   +24     
=======================================
+ Hits        12486    12493    +7     
  Misses       1722     1722           

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[yusukebe]

Hey @usualoma. I want to know your thoughts on this.

[usualoma]

@yusukebe
Ah I see, this is very nice!

Alternatively, how about the following. It simplifies the definition and opens up the possibility for users themselves to use "errors implementing getResponse()", other than hono’s HTTPException. The behaviour would change if an existing application used "errors implementing getResponse()", but, well, there would be no such application.

diff --git a/src/hono-base.ts b/src/hono-base.ts
index f3e9ad03..858d65db 100644
--- a/src/hono-base.ts
+++ b/src/hono-base.ts
@@ -7,7 +7,6 @@
 import { compose } from './compose'
 import { Context } from './context'
 import type { ExecutionContext } from './context'
-import { HTTPException } from './http-exception'
 import { HonoRequest } from './request'
 import type { Router } from './router'
 import { METHODS, METHOD_NAME_ALL, METHOD_NAME_ALL_LOWERCASE } from './router'
@@ -21,6 +20,7 @@ import type {
   MergeSchemaPath,
   MiddlewareHandler,
   MiddlewareHandlerInterface,
+  HTTPResponseError,
   Next,
   NotFoundHandler,
   OnHandlerInterface,
@@ -38,8 +38,8 @@ const notFoundHandler = (c: Context) => {
   return c.text('404 Not Found', 404)
 }
 
-const errorHandler = (err: Error, c: Context) => {
-  if (err instanceof HTTPException) {
+const errorHandler = (err: Error | HTTPResponseError, c: Context) => {
+  if ('getResponse' in err) {
     return err.getResponse()
   }
   console.error(err)
diff --git a/src/types.ts b/src/types.ts
index 2178e5c1..87691b01 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -91,8 +91,12 @@ export type H<
 > = Handler<E, P, I, R> | MiddlewareHandler<E, P, I>
 
 export type NotFoundHandler<E extends Env = any> = (c: Context<E>) => Response | Promise<Response>
+
+export interface HTTPResponseError extends Error {
+  getResponse: () => Response
+}
 export type ErrorHandler<E extends Env = any> = (
-  err: Error,
+  err: Error | HTTPResponseError,
   c: Context<E>
 ) => Response | Promise<Response>

[yusukebe]

@usualoma Thank you for the suggestion!

I also thought it was okay to check getResponse only first. As you said, we can ignore other applications that have "errors implementing getResponse()" since they are very rare or do not exist. So, I'll follow your idea.

[yusukebe]

@usualoma

Can you create the new PR with your patch?

[usualoma]

@yusukebe Created! #2898

[yusukebe]

This is not necessary now since #2898 has been merged.