From 06c9cfbb4730d987408c0fa1922c595bed680d53 Mon Sep 17 00:00:00 2001
From: Churchill Lee <churchill@piktochart.com>
Date: Wed, 28 Jun 2017 10:52:07 +0800
Subject: [PATCH 1/2] fix(dataset): check if property exist before deleting

in Safari, when it is `use strict`, if the dataset property is removed in DOM
deleting it again will cause an error

closes #309
---
 src/modules/dataset.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/modules/dataset.ts b/src/modules/dataset.ts
index 3af23d2..d9070ea 100755
--- a/src/modules/dataset.ts
+++ b/src/modules/dataset.ts
@@ -19,7 +19,7 @@ function updateDataset(oldVnode: VNode, vnode: VNode): void {
 
   for (key in oldDataset) {
     if (!dataset[key]) {
-      if (d) {
+      if (d && d[key]) {
         delete d[key];
       } else {
         elm.removeAttribute('data-' + key.replace(CAPS_REGEX, '-$&').toLowerCase());
@@ -38,4 +38,4 @@ function updateDataset(oldVnode: VNode, vnode: VNode): void {
 }
 
 export const datasetModule = {create: updateDataset, update: updateDataset} as Module;
-export default datasetModule;
\ No newline at end of file
+export default datasetModule;

From 16b14888b7524005acc6c741d7da0700b94d292f Mon Sep 17 00:00:00 2001
From: Churchill Lee <churchill@piktochart.com>
Date: Sat, 1 Jul 2017 12:22:18 +0800
Subject: [PATCH 2/2] refactor(dataset): protect delete invocation only

---
 src/modules/dataset.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/modules/dataset.ts b/src/modules/dataset.ts
index d9070ea..a49204b 100755
--- a/src/modules/dataset.ts
+++ b/src/modules/dataset.ts
@@ -19,8 +19,10 @@ function updateDataset(oldVnode: VNode, vnode: VNode): void {
 
   for (key in oldDataset) {
     if (!dataset[key]) {
-      if (d && d[key]) {
-        delete d[key];
+      if (d) {
+        if (key in d) {
+          delete d[key];
+        }
       } else {
         elm.removeAttribute('data-' + key.replace(CAPS_REGEX, '-$&').toLowerCase());
       }