Add standard properties to wasm.

src/wasm/mod.rs

@@ -1,5 +1,6 @@
 mod document;
 mod macros;
 mod parse_result;
+mod standard_properties;
 
 pub(crate) use parse_result::ParseResult;

src/wasm/standard_properties.rs

@@ -0,0 +1,19 @@
+use organic::types::PostBlank;
+use serde::Deserialize;
+use serde::Serialize;
+
+use super::macros::to_wasm;
+
+#[derive(Serialize, Deserialize)]
+pub(crate) struct WasmStandardProperties {
+    begin: Option<usize>,
+    end: Option<usize>,
+    contents_begin: Option<usize>,
+    contents_end: Option<usize>,
+    post_blank: Option<PostBlank>,
+}
+
+to_wasm!(WasmStandardProperties, Document<'s>, original, document, {
+    // foo
+    todo!()
+});