Implement event/response roundtrip (#49)

client/web/wasm/src/lib.rs

@@ -4,23 +4,27 @@ pub mod viewport;
 pub mod window;
 pub mod wrappers;
 
-use graphite_editor_core::Editor;
+use graphite_editor_core::{events::Response, Callback, Editor};
 use std::cell::RefCell;
 use wasm_bindgen::prelude::*;
 
 // the thread_local macro provides a way to initialize static variables with non-constant functions
-thread_local! {pub static EDITOR_STATE: RefCell<Editor> = RefCell::new(Editor::new())}
+thread_local! {pub static EDITOR_STATE: RefCell<Editor> = RefCell::new(Editor::new(Box::new(handle_response)))}
 
 #[wasm_bindgen(start)]
 pub fn init() {
 	utils::set_panic_hook();
 }
 
-/// Send events
-#[wasm_bindgen]
-pub fn handle_event(event_name: String) {
-	// TODO: add payload
-	todo!()
+fn handle_response(response: Response) {
+	match response {
+		Response::UpdateCanvas => update_canvas(),
+	}
+}
+
+#[wasm_bindgen(module = "/../src/wasm-callback-processor.js")]
+extern "C" {
+	fn update_canvas();
 }
 
 #[wasm_bindgen]