consolidate js functions

Former-commit-id: 3b8d3ff5e3

src/js.rs

@@ -0,0 +1,19 @@
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+extern "C" {
+    #[wasm_bindgen(js_namespace = console)]
+    pub fn log(a: &str);
+
+    #[wasm_bindgen(js_namespace = Math)]
+    pub fn random() -> f64;
+
+    #[wasm_bindgen(js_namespace = Date)]
+    pub fn now() -> f64;
+}
+
+macro_rules! console_log {
+    ($($t:tt)*) => (log(&format_args!($($t)*).to_string()))
+}
+
+pub(crate) use console_log;