feat: expose HttpError for clients (#3080)

This PR exposes the `HttpError` class for clients. 

To do that I needed to make the error message optional to avoid bloating
up the bundle with lots of status strings.

Fixes #2995

---------

Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>

Author: marvinhagemeister

packages/fresh/src/app.ts

@@ -12,6 +12,7 @@ import { mergePath, type Method, UrlPatternRouter } from "./router.ts";
 import type { FreshConfig, ResolvedFreshConfig } from "./config.ts";
 import type { BuildCache } from "./build_cache.ts";
 import { HttpError } from "./error.ts";
+import { STATUS_TEXT } from "@std/http/status";
 import type { LayoutConfig, MaybeLazy, Route, RouteConfig } from "./types.ts";
 import type { RouteComponent } from "./segments.ts";
 import {
@@ -55,7 +56,8 @@ const DEFAULT_ERROR_HANDLER = async <State>(ctx: Context<State>) => {
       // deno-lint-ignore no-console
       console.error(error);
     }
-    return new Response(error.message, { status: error.status });
+    const message = error.message || STATUS_TEXT[error.status];
+    return new Response(message, { status: error.status });
   }
 
   // deno-lint-ignore no-console

packages/fresh/src/error.ts

@@ -1,4 +1,4 @@
-import { type ErrorStatus, STATUS_TEXT } from "@std/http/status";
+import type { ErrorStatus } from "@std/http/status";
 
 export type { ErrorStatus };
 
@@ -68,7 +68,7 @@ export class HttpError extends Error {
    */
   constructor(
     status: ErrorStatus,
-    message: string = STATUS_TEXT[status],
+    message?: string,
     options?: ErrorOptions,
   ) {
     super(message, options);

packages/fresh/src/error_test.ts

@@ -4,11 +4,20 @@ import { HttpError } from "./error.ts";
 Deno.test("HttpError", () => {
   const err = new HttpError(404);
   expect(err.status).toEqual(404);
-  expect(err.message).toEqual("Not Found");
   expect(typeof err.stack).toEqual("string");
 
   const err2 = new HttpError(500);
   expect(err2.status).toEqual(500);
-  expect(err2.message).toEqual("Internal Server Error");
   expect(typeof err2.stack).toEqual("string");
 });
+
+Deno.test("HttpError - message", () => {
+  const err = new HttpError(500, "foo");
+  expect(err.message).toEqual("foo");
+});
+
+Deno.test("HttpError - cause", () => {
+  const causeErr = new Error();
+  const err = new HttpError(500, "foo", { cause: causeErr });
+  expect(err.cause).toEqual(causeErr);
+});

packages/fresh/src/runtime/shared.ts

@@ -2,6 +2,8 @@ import type { ComponentChildren, VNode } from "preact";
 import { BUILD_ID } from "@fresh/build-id";
 import { assetInternal, assetSrcSetInternal } from "./shared_internal.ts";
 
+export { HttpError } from "../error.ts";
+
 /**
  * Returns true when the current runtime is the browser and false otherwise. This is used for guard runtime-dependent code.
  * Shorthand for the following: