Prevent page number from incrementing early on very tall screens (#372)

internetarchive · May 8, 2024 · 6b25314 · 6b25314
1 parent 121531f
commit 6b25314
Showing 1 changed file with 7 additions and 2 deletions.
diff --git a/src/collection-browser.ts b/src/collection-browser.ts
@@ -1461,8 +1461,13 @@ export class CollectionBrowser
     if (this.isScrollingToCell) return;
     const { visibleCellIndices } = e.detail;
     if (visibleCellIndices.length === 0) return;
-    const lastVisibleCellIndex =
-      visibleCellIndices[visibleCellIndices.length - 1];
+
+    // For page determination, do not count more than a single page of visible cells,
+    // since otherwise patrons using very tall screens will be treated as one page
+    // further than they actually are.
+    const lastIndexWithinCurrentPage =
+      Math.min(this.pageSize, visibleCellIndices.length) - 1;
+    const lastVisibleCellIndex = visibleCellIndices[lastIndexWithinCurrentPage];
     const lastVisibleCellPage =
       Math.floor(lastVisibleCellIndex / this.pageSize) + 1;
     if (this.currentPage !== lastVisibleCellPage) {