improve perf => _filterNodeInRoot (8ms for killer, 1.5ms short)

Author: Gorash

packages/plugin-dom-layout/src/DomLayoutEngine.ts

@@ -122,9 +122,7 @@ export class DomLayoutEngine extends LayoutEngine {
         this._currentlyRedrawing = true;
 
         if (nodes) {
-            nodes = nodes.filter(node => {
-                return node.ancestors().pop() === this.root;
-            });
+            nodes = this._filterNodeInRoot(nodes);
         } else {
             nodes = [];
             // Redraw all.
@@ -221,6 +219,26 @@ export class DomLayoutEngine extends LayoutEngine {
     // Private
     //--------------------------------------------------------------------------
 
+    private _filterNodeInRoot(nodes: VNode[]): VNode[] {
+        const ancestorInRoot = new Set<VNode>();
+        const nodesToKeep: VNode[] = [];
+        for (const node of nodes) {
+            const parents: VNode[] = [];
+            let ancestor = node.parent;
+            while (ancestor) {
+                if (ancestor === this.root || ancestorInRoot.has(ancestor)) {
+                    nodesToKeep.push(node);
+                    for (const parent of parents) {
+                        ancestorInRoot.add(parent);
+                    }
+                    break;
+                }
+                parents.push(ancestor);
+                ancestor = ancestor.parent;
+            }
+        }
+        return nodesToKeep;
+    }
     /**
      * Render the given VSelection as a DOM selection in the given target.
      *