From 9c9f2726dcde0256e836ab4a84be115cb426401b Mon Sep 17 00:00:00 2001
From: Marais Rossouw <me@maraisr.com>
Date: Fri, 5 Jan 2018 20:30:06 +1000
Subject: [PATCH] fix: silently ignore a verticle animation when no item
 (#3757)

If when the verticleAnimationFrame callback fires, and the item no longer exists, (it has no parent), then we need to silently ignore that frame
---
 lib/timeline/Core.js     |  2 +-
 lib/timeline/Timeline.js |  9 ++++++++
 test/Timeline.test.js    | 44 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 test/Timeline.test.js

diff --git a/lib/timeline/Core.js b/lib/timeline/Core.js
index 719c77cf..597fb753 100644
--- a/lib/timeline/Core.js
+++ b/lib/timeline/Core.js
@@ -137,7 +137,7 @@ Core.prototype._create = function (container) {
   // emitted via emitter
   this.hammer = new Hammer(this.dom.root);
   var pinchRecognizer = this.hammer.get('pinch').set({enable: true});
-  hammerUtil.disablePreventDefaultVertically(pinchRecognizer);
+  pinchRecognizer && hammerUtil.disablePreventDefaultVertically(pinchRecognizer);
   this.hammer.get('pan').set({threshold:5, direction: Hammer.DIRECTION_HORIZONTAL});
   this.listeners = {};
 
diff --git a/lib/timeline/Timeline.js b/lib/timeline/Timeline.js
index 7310e623..84b35c91 100644
--- a/lib/timeline/Timeline.js
+++ b/lib/timeline/Timeline.js
@@ -448,6 +448,10 @@ Timeline.prototype.focus = function(id, options) {
     var verticalAnimationFrame = function(ease, willDraw, done) {
       var verticalScroll = getItemVerticalScroll(me, item);
 
+      if (verticalScroll === false) {
+        return; // We don't need to scroll, so do nothing
+      }
+
       if(!initialVerticalScroll) {
         initialVerticalScroll = verticalScroll;
       }
@@ -560,6 +564,11 @@ function getEnd(item) {
  * @return {{shouldScroll: bool, scrollOffset: number, itemTop: number}}
  */
 function getItemVerticalScroll(timeline, item) {
+  if (!item.parent) {
+    // The item no longer exists, so ignore this focus.
+    return false;
+  }
+
   var leftHeight = timeline.props.leftContainer.height;
   var contentHeight = timeline.props.left.height;
   
diff --git a/test/Timeline.test.js b/test/Timeline.test.js
new file mode 100644
index 00000000..355e3ffb
--- /dev/null
+++ b/test/Timeline.test.js
@@ -0,0 +1,44 @@
+var DataSet = require('../lib/DataSet');
+var Timeline = require('../lib/timeline/Timeline');
+
+describe('Timeline', function () {
+	before(function () {
+		this.jsdom = require('jsdom-global')({
+			pretendToBeVisual: true
+		});
+		global['Element'] = window.Element;
+		global['requestAnimationFrame'] = function(cb) {
+			cb();
+		};
+	});
+
+	after(function () {
+		this.jsdom();
+	});
+
+	it('should not throw when updating data in close succession', function (done) {
+		var timeline = new Timeline(document.createElement('div'), []);
+
+		var events = [
+			{start: new Date(), id: 1},
+			{start: new Date(), id: 2}
+		];
+
+		timeline
+			.setItems(new DataSet(events));
+
+		setTimeout(function() {
+			timeline
+				.setItems(new DataSet([
+					{start: new Date(), id: 3},
+					{start: new Date(), id: 4},
+					{start: new Date(), id: 5}
+				]));
+
+			done();
+		}, 5);
+
+		timeline
+			.setSelection([events[0].id], {animation: false});
+	});
+});