From 38ed8680cb1e8089c3749d7d1949b88a9dcf4e52 Mon Sep 17 00:00:00 2001
From: Chen Kai <281165273grape@gmail.com>
Date: Mon, 13 Jul 2026 09:47:28 -0400
Subject: [PATCH] fix(dsl): support class pointer arguments

---
 examples/js_dsl/mod.test.ts | 13 +++++++++++++
 examples/js_dsl/mod.zig     |  5 +++++
 src/js/wrap_function.zig    |  2 +-
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/examples/js_dsl/mod.test.ts b/examples/js_dsl/mod.test.ts
index a09f71b..42db759 100644
--- a/examples/js_dsl/mod.test.ts
+++ b/examples/js_dsl/mod.test.ts
@@ -227,6 +227,19 @@ describe("Counter class", () => {
 		expect(c.getCount()).toEqual(2);
 	});
 
+	it("passes class pointers to exported functions", () => {
+		const c = new mod.Counter(3);
+		mod.incrementCounter(c);
+		expect(c.getCount()).toEqual(4);
+	});
+
+	it("rejects the wrong class for pointer arguments", () => {
+		expectTypeErrorWithMessage(
+			() => mod.incrementCounter(new mod.Buffer(4)),
+			"Argument 1 must be an instance of mod.Counter",
+		);
+	});
+
 	it("isAbove returns boolean", () => {
 		const c = new mod.Counter(10);
 		expect(c.isAbove(5)).toBe(true);
diff --git a/examples/js_dsl/mod.zig b/examples/js_dsl/mod.zig
index 25b6326..99f5438 100644
--- a/examples/js_dsl/mod.zig
+++ b/examples/js_dsl/mod.zig
@@ -272,6 +272,11 @@ pub const Counter = struct {
     }
 };
 
+/// Increment a counter passed as a class pointer argument.
+pub fn incrementCounter(counter: *Counter) void {
+    counter.count += 1;
+}
+
 /// A resource-owning buffer class demonstrating deinit.
 pub const Buffer = struct {
     pub const js_meta = js.class(.{});
diff --git a/src/js/wrap_function.zig b/src/js/wrap_function.zig
index a3a36bb..fcaf689 100644
--- a/src/js/wrap_function.zig
+++ b/src/js/wrap_function.zig
@@ -167,7 +167,7 @@ pub fn convertArg(comptime T: type, raw: napi.c.napi_value, env: napi.c.napi_env
     }
     switch (@typeInfo(T)) {
         .pointer => |ptr| {
-            if (ptr.size == .one and class_meta.isClassType(ptr.child)) {
+            if (comptime ptr.size == .one and class_meta.isClassType(ptr.child)) {
                 const e = napi.Env{ .env = env };
                 return e.unwrapChecked(ptr.child, value, class_runtime.typeTag(ptr.child)) catch error.TypeMismatch;
             }