fix: application errors dispatched after default logic

Fixes #630

application.test.ts

@@ -691,6 +691,27 @@ Deno.test({
   },
 });
 
+Deno.test({
+  name: "errors call event handler properly",
+  async fn() {
+    const [serverConstructor, responseStack] = setup([]);
+    const app = new Application({ serverConstructor, logErrors: false });
+    app.use((ctx) => {
+      ctx.throw(400, "Bad Request");
+    });
+    const errStatusStack: (Status | undefined)[] = [];
+    app.addEventListener("error", (evt) => {
+      errStatusStack.push(evt.context?.response.status);
+    });
+    await app.listen({ port: 8000 });
+    const [response] = responseStack;
+    assertEquals(response.status, 400);
+    assertEquals(errStatusStack.length, 1);
+    assertEquals(errStatusStack[0], Status.BadRequest);
+    teardown();
+  },
+});
+
 Deno.test({
   name: "caught errors don't dispatch error events",
   async fn() {

application.ts

@@ -418,8 +418,10 @@ export class Application<AS extends State = Record<string, any>>
       error = new Error(`non-error thrown: ${JSON.stringify(error)}`);
     }
     const { message } = error;
-    this.dispatchEvent(new ApplicationErrorEvent({ context, message, error }));
     if (!context.response.writable) {
+      this.dispatchEvent(
+        new ApplicationErrorEvent({ context, message, error }),
+      );
       return;
     }
     for (const key of [...context.response.headers.keys()]) {
@@ -438,6 +440,7 @@ export class Application<AS extends State = Record<string, any>>
         ? error.status
         : 500;
     context.response.body = error.expose ? error.message : STATUS_TEXT[status];
+    this.dispatchEvent(new ApplicationErrorEvent({ context, message, error }));
   }
 
   /** Processing registered middleware on each request. */