diff --git a/main.js b/main.js
index a2e2ea1..a116c3c 100644
--- a/main.js
+++ b/main.js
@@ -148,7 +148,7 @@ async function run() {
 
     const width = 40;
     const height = 50;
-    const universe = Universe.new(width, height);
+    const universe = new Universe(width, height);
 
     const TIMEFACTOR = 10000.0;
     const MAX_DT = 2.0/Math.max(width, height);
diff --git a/src/lib.rs b/src/lib.rs
index c301b07..3f64d74 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,6 +22,7 @@ pub struct Universe {
 
 #[wasm_bindgen]
 impl Universe {
+    #[wasm_bindgen(constructor)]
     pub fn new(width: u32, height: u32) -> Self {
         Self {
             sys: (System::new(width, height), System::new(width, height)),