Add original field name to wasm macro.

src/wasm/document.rs

@@ -23,9 +23,20 @@ pub(crate) struct WasmDocument<'s> {
 to_wasm!(
     WasmDocument<'s>,
     Document<'s>,
+    original,
     wasm_context,
     standard_properties,
     {
+        let additional_properties: Vec<(String, &str)> = original
+            .get_additional_properties()
+            .map(|node_property| {
+                (
+                    format!(":{}", node_property.property_name.to_uppercase()),
+                    node_property.value.unwrap_or(""),
+                )
+            })
+            .collect();
+
         Ok(WasmDocument {
             standard_properties,
             additional_properties: Vec::new(),