fix: handle headerLinkElements safely

HEIGE-PCloud · Jun 11, 2024 · 2543464 · 2543464
1 parent 90c35b5
commit 2543464
Showing 1 changed file with 17 additions and 15 deletions.
diff --git a/assets/js/theme.ts b/assets/js/theme.ts
@@ -540,7 +540,7 @@ function initToc() {
     const toc = document.getElementById("toc-auto");
     const tocLinkElements = tocCore.querySelectorAll("a:first-child");
     const tocLiElements = tocCore.getElementsByTagName("li");
-    const headerLinkElements = document.getElementsByClassName("headerLink");
+    const headerLinkElements = document.getElementsByClassName("headerLink") as HTMLCollectionOf<HTMLHeadingElement>;
     const headerIsFixed =
       document.body.getAttribute("header-desktop") !== "normal";
     const headerHeight = document.getElementById("header-desktop").offsetHeight;
@@ -579,20 +579,22 @@ function initToc() {
         const INDEX_SPACING = TOP_SPACING + window.newScrollTop;
         // If the INDEX_SPACING is below the last header link
         // activate the last element
-        if (
-          headerLinkElements[headerLinkElements.length - 1].offsetTop <
-          INDEX_SPACING
-        ) {
-          activeTocIndex = headerLinkElements.length - 1;
-        } else {
-          // Otherwise activate the element that is in between
-          // Use offsetTop instead of getBoundingClientRect().top for better performance
-          for (let i = 0; i < headerLinkElements.length - 1; i++) {
-            const thisTop = headerLinkElements[i].offsetTop;
-            const nextTop = headerLinkElements[i + 1].offsetTop;
-            if (thisTop <= INDEX_SPACING && nextTop > INDEX_SPACING) {
-              activeTocIndex = i;
-              break;
+        if (headerLinkElements.length > 0) {
+          if (
+            headerLinkElements[headerLinkElements.length - 1].offsetTop <
+            INDEX_SPACING
+          ) {
+            activeTocIndex = headerLinkElements.length - 1;
+          } else {
+            // Otherwise activate the element that is in between
+            // Use offsetTop instead of getBoundingClientRect().top for better performance
+            for (let i = 0; i < headerLinkElements.length - 1; i++) {
+              const thisTop = headerLinkElements[i].offsetTop;
+              const nextTop = headerLinkElements[i + 1].offsetTop;
+              if (thisTop <= INDEX_SPACING && nextTop > INDEX_SPACING) {
+                activeTocIndex = i;
+                break;
+              }
             }
           }
         }