Add logging and panic hook

Cargo.toml

@@ -19,6 +19,7 @@ wasm-bindgen = "0.2.100"
 # code size when deploying.
 console_error_panic_hook = { version = "0.1.7", optional = true }
 js-sys = "0.3.77"
+web-sys = { version = "0.3.77", features = ["console"] }
 
 [dev-dependencies]
 wasm-bindgen-test = "0.3.50"

src/lib.rs

@@ -4,6 +4,12 @@ use std::fmt;
 
 use wasm_bindgen::prelude::*;
 
+macro_rules! log {
+    ( $( $t:tt )* ) => {
+        web_sys::console::log_1(&format!( $( $t )* ).into());
+    };
+}
+
 #[wasm_bindgen]
 extern "C" {
     fn alert(s: &str);
@@ -55,6 +61,8 @@ impl Universe {
 #[wasm_bindgen]
 impl Universe {
     pub fn tick(&mut self) {
+        utils::set_panic_hook();
+
         let mut next = self.cells.clone();
 
         for row in 0..self.height {
@@ -63,6 +71,14 @@ impl Universe {
                 let cell = self.cells[idx];
                 let live_neighbors = self.live_neighbor_count(row, col);
 
+                //log!(
+                //    "cell[{}, {}] is initially {:?} and has {} live neighbors",
+                //    row,
+                //    col,
+                //    cell,
+                //    live_neighbors
+                //);
+
                 let next_cell = match (cell, live_neighbors) {
                     // Rule 1: Any live cell with fewer than two live neighbours
                     // dies, as if caused by underpopulation.
@@ -80,6 +96,8 @@ impl Universe {
                     (otherwise, _) => otherwise,
                 };
 
+                //log!("    it becomes {:?}", next_cell);
+
                 next[idx] = next_cell;
             }
         }