fixes 8 of nick's list

frontend/src/hooks.ts

@@ -0,0 +1,19 @@
+import { useEffect, RefObject } from 'react';
+
+export function useOutsideAlerter<T extends HTMLElement>(
+  ref: RefObject<T>,
+  handler: () => void,
+  deps: any[],
+) {
+  useEffect(() => {
+    function handleClickOutside(this: Document, event: MouseEvent) {
+      if (ref.current && !ref.current.contains(event.target as Node)) {
+        handler();
+      }
+    }
+    document.addEventListener('mousedown', handleClickOutside);
+    return () => {
+      document.removeEventListener('mousedown', handleClickOutside);
+    };
+  }, [ref, ...deps]);
+}