diff --git a/dtool/src/parser-inc/emscripten/heap.h b/dtool/src/parser-inc/emscripten/heap.h
new file mode 100644
index 0000000000..b4047a9fb8
--- /dev/null
+++ b/dtool/src/parser-inc/emscripten/heap.h
@@ -0,0 +1,9 @@
+
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+#include <emscripten/emscripten.h>
+
+#define WASM_PAGE_SIZE 65536
+#define EMSCRIPTEN_PAGE_SIZE WASM_PAGE_SIZE