Fix bug with decorators not being generated in `export default class` (#3577)

* Fix bug with decorators not being generated in `export default class`

* Update decorator-export-default-class-fixture.ts

---------

Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>

3 files changed, 27 insertions, 1 deletions

diff --git a/src/js_parser.zig b/src/js_parser.zig
index 230a09fd0..df5c84294 100644
--- a/src/js_parser.zig
+++ b/src/js_parser.zig
@@ -18146,7 +18146,18 @@ fn NewParser_(
                                         data.default_name = createDefaultName(p, stmt.loc) catch unreachable;
                                     }
 
-                                    stmts.append(stmt.*) catch unreachable;
+                                    var class_stmts = p.lowerClass(.{ .stmt = s2 });
+
+                                    if (class_stmts.len > 1) {
+                                        std.debug.assert(class_stmts[0].data == .s_class);
+                                        data.value.stmt = class_stmts[0];
+                                        stmts.append(stmt.*) catch {};
+                                        stmts.appendSlice(class_stmts[1..]) catch {};
+                                    } else {
+                                        data.value.stmt = class_stmts[0];
+                                        stmts.append(stmt.*) catch {};
+                                    }
+
                                     return;
                                 },
                                 else => {},
diff --git a/test/transpiler/decorator-export-default-class-fixture.ts b/test/transpiler/decorator-export-default-class-fixture.ts
new file mode 100644
index 000000000..901c17718
--- /dev/null
+++ b/test/transpiler/decorator-export-default-class-fixture.ts
@@ -0,0 +1,10 @@
+function decorator(target: any, propertyKey: any) {
+  target[propertyKey + "decorated"] = true;
+}
+
+export default class DecoratedClass {
+  @decorator
+  method() {
+    return 42;
+  }
+}
diff --git a/test/transpiler/decorators.test.ts b/test/transpiler/decorators.test.ts
index 8769ea2bc..ad0980930 100644
--- a/test/transpiler/decorators.test.ts
+++ b/test/transpiler/decorators.test.ts
@@ -1,5 +1,6 @@
 // @ts-nocheck
 import { test, expect, describe } from "bun:test";
+import DecoratedClass from "./decorator-export-default-class-fixture";
 
 test("decorator order of evaluation", () => {
   let counter = 0;
@@ -988,3 +989,7 @@ describe("constructor statements", () => {
     expect(a.v2).toBe(0);
   });
 });
+
+test("export default class works", () => {
+  expect(new DecoratedClass()["methoddecorated"]).toBe(true);
+});