fix: scroll lagging on pages with TOC and large number of headers (#148)

reduces the number of TOC refreshes by throttling calls to the DoxygenAwesomeInteractiveToc.update() method.

Fixes #147

Co-authored-by: jothepro <github@jothe.pro>

Author: iamAyushChamoli

doxygen-awesome-interactive-toc.js

@@ -55,9 +55,7 @@ class DoxygenAwesomeInteractiveToc {
                         headerNode: document.getElementById(id)
                     })
 
-                    document.getElementById("doc-content")?.addEventListener("scroll", () => {
-                        DoxygenAwesomeInteractiveToc.update()
-                    })
+                    document.getElementById("doc-content")?.addEventListener("scroll",this.throttle(DoxygenAwesomeInteractiveToc.update, 100))
                 })
                 DoxygenAwesomeInteractiveToc.update()
             }
@@ -78,4 +76,16 @@ class DoxygenAwesomeInteractiveToc {
         active?.classList.add("active")
         active?.classList.remove("aboveActive")
     }
-}
+
+    static throttle(func, delay) {
+        let lastCall = 0;
+        return function (...args) {
+            const now = new Date().getTime();
+            if (now - lastCall < delay) {
+                return;
+            }
+            lastCall = now;
+            return setTimeout(() => {func(...args)}, delay);
+        };
+    }
+}