Add frontend tests and other stuff

frontend/src/lib.rs

@@ -0,0 +1,35 @@
+mod utils;
+
+use wasm_bindgen::prelude::*;
+use web_sys::console;
+
+// When the `wee_alloc` feature is enabled, use `wee_alloc` as the global
+// allocator.
+#[cfg(feature = "wee_alloc")]
+#[global_allocator]
+static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
+
+#[wasm_bindgen]
+extern {
+    fn alert(s: &str);
+}
+
+#[wasm_bindgen]
+pub fn greet(name: &str) {
+    alert(&format!("Hello, {}!", name));
+    console::log_1(&"Hello bg".into());
+}
+
+#[wasm_bindgen(start)]
+pub fn main() -> Result<(), JsValue> {
+    let window = web_sys::window().expect("no global `window` exists");
+    let document = window.document().expect("should have a document on window");
+    let body = document.body().expect("document should have a body");
+
+    let val = document.create_element("p")?;
+    val.set_inner_html("Hello from Rust!");
+
+    body.append_child(&val)?;
+
+    Ok(())
+}

frontend/src/utils.rs

@@ -0,0 +1,10 @@
+pub fn set_panic_hook() {
+    // When the `console_error_panic_hook` feature is enabled, we can call the
+    // `set_panic_hook` function at least once during initialization, and then
+    // we will get better error messages if our code ever panics.
+    //
+    // For more details see
+    // https://github.com/rustwasm/console_error_panic_hook#readme
+    #[cfg(feature = "console_error_panic_hook")]
+    console_error_panic_hook::set_once();
+}