fix: make console error for thrown unkown errors

src/app.ts

@@ -1,7 +1,7 @@
 import type http from 'http'
 import { withoutTrailingSlash } from 'ufo'
 import { defineLazyEventHandler, toEventHandler, createEvent, isEventHandler, defineEventHandler } from './event'
-import { createError, sendError } from './error'
+import { createError, sendError, isError } from './error'
 import { send, sendStream, isStream, MIMES } from './utils'
 import type { Handler, LazyHandler, Middleware } from './types'
 import type { EventHandler, CompatibilityEvent, CompatibilityEventHandler, LazyEventHandler } from './event'
@@ -62,6 +62,9 @@ export function createApp (options: AppOptions = {}): App {
       if (options.onError) {
         await options.onError(err as Error, event)
       }
+      if (!isError(err)) {
+        console.error('[h3]', err) // eslint-disable-line no-console
+      }
       await sendError(event, err as Error, !!options.debug)
     }
   }

src/error.ts

@@ -56,13 +56,7 @@ export function createError (input: Partial<H3Error>): H3Error {
  *  In the debug mode the stack trace of errors will be return in response.
  */
 export function sendError (event: CompatibilityEvent, error: Error | H3Error, debug?: boolean) {
-  let h3Error: H3Error
-  if (error instanceof H3Error) {
-    h3Error = error
-  } else {
-    console.error('[h3]', error) // eslint-disable-line no-console
-    h3Error = createError(error)
-  }
+  const h3Error = isError(error) ? error : createError(error)
 
   if (event.res.writableEnded) {
     return
@@ -85,3 +79,7 @@ export function sendError (event: CompatibilityEvent, error: Error | H3Error, de
   event.res.setHeader('Content-Type', MIMES.json)
   event.res.end(JSON.stringify(responseBody, null, 2))
 }
+
+export function isError (input: any): input is H3Error {
+  return input instanceof H3Error
+}