diff --git a/app/src/actions/Settings.ts b/app/src/actions/Settings.ts
index e69a178..c423efc 100644
--- a/app/src/actions/Settings.ts
+++ b/app/src/actions/Settings.ts
@@ -149,9 +149,10 @@ function autoExpandLimitForTree(tree: q.Tree<TopicViewModel>) {
   if (!tree) {
     return 0
   }
+
   function closestExistingLimit(i: number): number {
-    const sorted = autoExpandLimitSet.sort((a, b) => Math.abs(a.limit - i) - Math.abs(b.limit - i))
-    return sorted[0]!.limit
+    const sorted = [...autoExpandLimitSet].sort((a, b) => Math.abs(a.limit - i) - Math.abs(b.limit - i))
+    return sorted[0].limit
   }
 
   const count = tree.childTopicCount()
diff --git a/app/src/components/Sidebar/Publish/Publish.tsx b/app/src/components/Sidebar/Publish/Publish.tsx
index 576efd0..87b594c 100644
--- a/app/src/components/Sidebar/Publish/Publish.tsx
+++ b/app/src/components/Sidebar/Publish/Publish.tsx
@@ -192,7 +192,7 @@ class Publish extends React.Component<Props, State> {
   }
 
   private history() {
-    const items = this.state.history.reverse().map(message => ({
+    const items = [...this.state.history].reverse().map(message => ({
       key: sha1(message.topic + message.payload),
       title: message.topic,
       value: message.payload || '',
diff --git a/app/src/components/Sidebar/ValueRenderer/MessageHistory.tsx b/app/src/components/Sidebar/ValueRenderer/MessageHistory.tsx
index 0b500f7..d1c6a40 100644
--- a/app/src/components/Sidebar/ValueRenderer/MessageHistory.tsx
+++ b/app/src/components/Sidebar/ValueRenderer/MessageHistory.tsx
@@ -79,7 +79,7 @@ class MessageHistory extends React.Component<Props, State> {
 
     const history = node.messageHistory.toArray()
     let previousMessage: q.Message | undefined = node.message
-    const historyElements = history.reverse().map((message, idx) => {
+    const historyElements = [...history].reverse().map((message, idx) => {
       const value = message.value ? Base64Message.toUnicodeString(message.value) : ''
       const element = {
         value,
diff --git a/app/src/components/UpdateNotifier.tsx b/app/src/components/UpdateNotifier.tsx
index 481c879..9deab94 100644
--- a/app/src/components/UpdateNotifier.tsx
+++ b/app/src/components/UpdateNotifier.tsx
@@ -180,7 +180,7 @@ class UpdateNotifier extends React.Component<Props, State> {
     let regex: RegExp
     if (os.platform() === 'darwin') {
       regex = /\.dmg$/
-    } else if (os.platform() === 'darwin') {
+    } else if (os.platform() === 'win32') {
       regex = /\.exe$/
     } else {
       regex = /\.AppImage$/
diff --git a/app/src/sortedNodes.tsx b/app/src/sortedNodes.tsx
index 352864b..e6cf151 100644
--- a/app/src/sortedNodes.tsx
+++ b/app/src/sortedNodes.tsx
@@ -4,16 +4,17 @@ import { TopicViewModel } from './model/TopicViewModel'
 
 export function sortedNodes(settings: SettingsState, treeNode: q.TreeNode<any>): Array<q.TreeNode<TopicViewModel>> {
   const topicOrder = settings.get('topicOrder')
-  let edges = treeNode.edgeArray
+  const edges = [...treeNode.edgeArray]
+
   if (topicOrder === TopicOrder.abc) {
-    edges = edges.sort((a, b) => a.name.localeCompare(b.name))
+    edges.sort((a, b) => a.name.localeCompare(b.name))
   }
-  let nodes = edges.map(edge => edge.target)
+  const nodes = edges.map(edge => edge.target)
   if (topicOrder === TopicOrder.messages) {
-    nodes = nodes.sort((a, b) => b.leafMessageCount() - a.leafMessageCount())
+    nodes.sort((a, b) => b.leafMessageCount() - a.leafMessageCount())
   }
   if (topicOrder === TopicOrder.topics) {
-    nodes = nodes.sort((a, b) => b.childTopicCount() - a.childTopicCount())
+    nodes.sort((a, b) => b.childTopicCount() - a.childTopicCount())
   }
   return nodes
 }