Fix all "var used instead of let or const" problems in background.js

app/scripts/background.js

@@ -421,13 +421,13 @@ function setupController (initState, initLangCode) {
    * The number reflects the current number of pending transactions or message signatures needing user approval.
    */
   function updateBadge () {
-    var label = ''
-    var unapprovedTxCount = controller.txController.getUnapprovedTxCount()
-    var unapprovedMsgCount = controller.messageManager.unapprovedMsgCount
-    var unapprovedPersonalMsgs = controller.personalMessageManager.unapprovedPersonalMsgCount
-    var unapprovedTypedMsgs = controller.typedMessageManager.unapprovedTypedMessagesCount
+    let label = ''
+    const unapprovedTxCount = controller.txController.getUnapprovedTxCount()
+    const unapprovedMsgCount = controller.messageManager.unapprovedMsgCount
+    const unapprovedPersonalMsgs = controller.personalMessageManager.unapprovedPersonalMsgCount
+    const unapprovedTypedMsgs = controller.typedMessageManager.unapprovedTypedMessagesCount
     const pendingProviderRequests = controller.providerApprovalController.store.getState().providerRequests.length
-    var count = unapprovedTxCount + unapprovedMsgCount + unapprovedPersonalMsgs + unapprovedTypedMsgs + pendingProviderRequests
+    const count = unapprovedTxCount + unapprovedMsgCount + unapprovedPersonalMsgs + unapprovedTypedMsgs + pendingProviderRequests
     if (count) {
       label = String(count)
     }
@@ -463,7 +463,7 @@ function openPopup () {
   triggerUi()
   return new Promise(
     (resolve) => {
-      var interval = setInterval(() => {
+      const interval = setInterval(() => {
         if (!notificationIsOpen) {
           clearInterval(interval)
           resolve()