init: it builds

um_wasm/src/lib.rs

@@ -0,0 +1,19 @@
+mod utils;
+
+use utils::set_panic_hook;
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+extern "C" {
+    fn alert(s: &str);
+}
+
+#[wasm_bindgen]
+pub fn init() {
+    set_panic_hook();
+}
+
+#[wasm_bindgen]
+pub fn greet() {
+    alert("hello world!");
+}