typescript width

src/client/width.js → src/client/width.ts

@@ -1,13 +1,13 @@
 // Override the width definition to use main instead of body (and also use a
 // ResizeObserver instead of listening for window resize events).
 export function width({Generators}) {
-  return Generators.observe((notify) => {
-    let width;
+  return Generators.observe((notify: (width: number) => void) => {
+    let width: number;
     const observer = new ResizeObserver(([entry]) => {
       const w = entry.contentRect.width;
       if (w !== width) notify((width = w));
     });
-    observer.observe(document.querySelector("main"));
+    observer.observe(document.querySelector<HTMLElement>("main")!);
     return () => observer.disconnect();
   });
 }