From f9f20eeb6fb33bcab08dfe4868ebcf5668177973 Mon Sep 17 00:00:00 2001
From: Hyunje Alex Jun <me@noraesae.net>
Date: Tue, 7 Jul 2015 15:25:16 +0900
Subject: [PATCH] Add null-check when updating or destroying an instance.

Throw an error when an instance is not found.
---
 src/js/plugin/destroy.js | 4 ++++
 src/js/plugin/update.js  | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/src/js/plugin/destroy.js b/src/js/plugin/destroy.js
index 6c8e33a..67bc2b9 100644
--- a/src/js/plugin/destroy.js
+++ b/src/js/plugin/destroy.js
@@ -10,6 +10,10 @@ var d = require('../lib/dom')
 module.exports = function (element) {
   var i = instances.get(element);
 
+  if (!i) {
+    throw new Error('perfect-scrollbar: instance not found');
+  }
+
   i.event.unbindAll();
   d.remove(i.scrollbarX);
   d.remove(i.scrollbarY);
diff --git a/src/js/plugin/update.js b/src/js/plugin/update.js
index 7585df0..5da6b18 100644
--- a/src/js/plugin/update.js
+++ b/src/js/plugin/update.js
@@ -11,6 +11,10 @@ var d = require('../lib/dom')
 module.exports = function (element) {
   var i = instances.get(element);
 
+  if (!i) {
+    throw new Error('perfect-scrollbar: instance not found');
+  }
+
   // Recalcuate negative scrollLeft adjustment
   i.negativeScrollAdjustment = i.isNegativeScroll ? element.scrollWidth - element.clientWidth : 0;