Merge pull request CirclonGroup#696 from jacmgh/fix/issue-463

adamkleingit · web-flow · commit 751594d25c59 · 2018-12-25T21:37:07.000+02:00
issue CirclonGroup#463 workaround
diff --git a/lib/models/tree-virtual-scroll.model.ts b/lib/models/tree-virtual-scroll.model.ts
@@ -144,6 +144,20 @@ export class TreeVirtualScroll {
     }, firstIndex);
 
     const viewportNodes = [];
+
+    // Loading async top nodes' children is too long.
+    // It happens when first node is visible withing viewport range (including Y_OFFSET).
+    // In that case firstIndex == 0 and lastIndex == visibleNodes.length - 1 (e.g. 1000),
+    // which means that it loops through every visibleNodes item and push them into viewportNodes array.
+    // lastIndex should not equal visibleNodes.length - 1, but something around 50-100 (depending on the viewport)
+    const nodeHeight = visibleNodes[0].treeModel.options.options.nodeHeight;
+    const renderedNodesMaxLength = (Y_OFFSET * 2 + this.viewportHeight) / nodeHeight;
+
+    // Something is probably wrong, prevent nodes from being pushed to an array.
+    if (lastIndex - firstIndex > renderedNodesMaxLength) {
+      return [];
+    }
+
     for (let i = firstIndex; i <= lastIndex; i++) {
       viewportNodes.push(visibleNodes[i]);
     }
