diff --git a/src/hb-wasm-api.hh b/src/hb-wasm-api.hh
index d7bfd322d..376ba1a7b 100644
--- a/src/hb-wasm-api.hh
+++ b/src/hb-wasm-api.hh
@@ -41,7 +41,15 @@
 #undef HB_WASM_BEGIN_DECLS
 #undef HB_WASM_END_DECLS
 
+
+#define nullref 0
 #define module_inst wasm_runtime_get_module_inst (exec_env)
+#define HB_REF2OBJ(obj) \
+  hb_##obj##_t *obj = nullptr; \
+  (void) wasm_externref_ref2obj (obj##ref, (void **) &obj)
+#define HB_OBJ2REF(obj) \
+  uint32_t obj##ref = nullref; \
+  (void) wasm_externref_obj2ref (module_inst, obj, &obj##ref)
 
 
 #include "hb-wasm-font.hh"
@@ -57,9 +65,12 @@ debugprint (HB_WASM_EXEC_ENV
 }}
 #endif
 
+
+#undef nullref
 #undef module_inst
 #undef HB_WASM_EXEC_ENV
-
+#undef HB_REF2OBJ
+#undef HB_OBJ2REF
 
 
   /* Define an array of NativeSymbol for the APIs to be exported.
diff --git a/src/hb-wasm-font.hh b/src/hb-wasm-font.hh
index 9a2272ebc..788261bf6 100644
--- a/src/hb-wasm-font.hh
+++ b/src/hb-wasm-font.hh
@@ -35,14 +35,13 @@ face_t
 font_get_face (HB_WASM_EXEC_ENV
 	       font_t fontref)
 {
-  hb_font_t *font;
-  if (unlikely (!wasm_externref_ref2obj (fontref, (void **) &font)))
-    return 0;
+  HB_REF2OBJ (font);
+  if (unlikely (!font))
+    return nullref;
 
   hb_face_t *face = hb_font_get_face (font);
 
-  uint32_t faceref = 0;
-  (void) wasm_externref_obj2ref (module_inst, face, &faceref);
+  HB_OBJ2REF (face);
   return faceref;
 }