From b7e741ab801417b7475f90785fb23639cf35ba09 Mon Sep 17 00:00:00 2001
From: "Manu Mtz.-Almeida" <manu.mtza@gmail.com>
Date: Sun, 12 Aug 2018 01:42:49 +0200
Subject: [PATCH] fix(virtual-scroll): fix viewportOffset calculation

fixes #14963
---
 core/src/components/virtual-scroll/test/basic.html    | 4 ++++
 core/src/components/virtual-scroll/virtual-scroll.tsx | 7 +++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/core/src/components/virtual-scroll/test/basic.html b/core/src/components/virtual-scroll/test/basic.html
index 629b095685..a44dc98749 100644
--- a/core/src/components/virtual-scroll/test/basic.html
+++ b/core/src/components/virtual-scroll/test/basic.html
@@ -20,6 +20,10 @@
           <ion-button onclick="addItems()">Add Items</ion-button>
         </ion-buttons>
       </ion-toolbar>
+      <ion-toolbar></ion-toolbar>
+      <ion-toolbar></ion-toolbar>
+      <ion-toolbar></ion-toolbar>
+      <ion-toolbar></ion-toolbar>
     </ion-header>
 
     <ion-content>
diff --git a/core/src/components/virtual-scroll/virtual-scroll.tsx b/core/src/components/virtual-scroll/virtual-scroll.tsx
index 9d2cc17a8d..80620568c3 100644
--- a/core/src/components/virtual-scroll/virtual-scroll.tsx
+++ b/core/src/components/virtual-scroll/virtual-scroll.tsx
@@ -11,6 +11,7 @@ import { Range, calcCells, calcHeightIndex, doRender, findCellIndex, getRange, g
 })
 export class VirtualScroll {
 
+  private contentEl?: HTMLElement;
   private scrollEl?: HTMLElement;
   private range: Range = { offset: 0, length: 0 };
   private timerUpdate: any;
@@ -121,6 +122,7 @@ export class VirtualScroll {
     }
     await contentEl.componentOnReady();
 
+    this.contentEl = contentEl;
     this.scrollEl = contentEl.getScrollElement();
     this.calcCells();
     this.updateState();
@@ -215,14 +217,15 @@ export class VirtualScroll {
   }
 
   private readVS() {
-    const { scrollEl, el } = this;
+    const { contentEl, scrollEl, el } = this;
     let topOffset = 0;
     let node: HTMLElement | null = el;
-    while (node && node !== scrollEl) {
+    while (node && node !== contentEl) {
       topOffset += node.offsetTop;
       node = node.parentElement;
     }
     this.viewportOffset = topOffset;
+    console.log(this.viewportOffset);
     if (scrollEl) {
       this.viewportHeight = scrollEl.offsetHeight;
       this.currentScrollTop = scrollEl.scrollTop;