The two-way callback.

Author: Dima Korolev

step09_wasm/code/src/lib.rs

@@ -2,11 +2,14 @@ use wasm_bindgen::prelude::*;
 
 #[wasm_bindgen]
 extern "C" {
-  fn js_callback(msg: &str);
+  fn js_log(msg: &str);
+  fn js_return_another_name() -> String;
 }
 
 #[wasm_bindgen]
 pub fn greet(name: &str) -> String {
-  js_callback(&format!("Callback from Rust, says {name}."));
+  js_log(&format!("Callback from Rust, says {name}."));
+  let another_name = js_return_another_name();
+  js_log(&format!("Another callback from Rust, says {another_name}."));
   format!("Wasm works, says {name}.")
 }

step09_wasm/code/web/index.js

@@ -1,9 +1,13 @@
 import init, { greet } from "./pkg/wasm.js";
 
-window.js_callback = (msg) => {
+window.js_log = (msg) => {
   console.log("Called the callback from Rust:", msg);
 };
 
+window.js_return_another_name = () => {
+  return "Max";
+};
+
 init().then(() => {
   document.getElementById("out").innerText = greet("Dima");
 });