ui: fix eslint errors

ui/src/main.js

@@ -24,7 +24,7 @@ export const i18n = new VueI18n({
 // Borrowed from http://tobyho.com/2012/07/27/taking-over-console-log/
 function intercept (method) {
   console[method] = function () {
-    var message = Array.prototype.slice.apply(arguments).join(' ')
+    const message = Array.prototype.slice.apply(arguments).join(' ')
     window.external.invoke(
       JSON.stringify({
         Log: {
@@ -37,7 +37,7 @@ function intercept (method) {
 }
 
 // See if we have access to the JSON interface
-var hasExternalInterface = false
+let hasExternalInterface = false
 try {
   window.external.invoke(JSON.stringify({
     Test: {}
@@ -60,8 +60,8 @@ if (hasExternalInterface) {
     )
   }
 
-  var methods = ['log', 'warn', 'error']
-  for (var i = 0; i < methods.length; i++) {
+  const methods = ['log', 'warn', 'error']
+  for (let i = 0; i < methods.length; i++) {
     intercept(methods[i])
   }
 }
@@ -97,7 +97,7 @@ function selectFileCallback (name) {
 
 window.selectFileCallback = selectFileCallback
 
-var app = new Vue({
+const app = new Vue({
   i18n: i18n,
   router: router,
   data: {
@@ -125,7 +125,8 @@ var app = new Vue({
   methods: {
     exit: function () {
       axios.get('/api/exit').catch(function (msg) {
-        var searchLocation = (app.metadata.install_path && app.metadata.install_path.length > 0) ? app.metadata.install_path
+        const searchLocation = (app.metadata.install_path && app.metadata.install_path.length > 0)
+          ? app.metadata.install_path
           : i18n.t('error.location_unknown')
 
         app.$router.replace({

ui/src/views/InstallPackages.vue

@@ -39,13 +39,13 @@ export default {
   },
   methods: {
     install: function () {
-      var that = this
-      var app = this.$root
+      const that = this
+      const app = this.$root
 
-      var results = {}
+      const results = {}
 
-      for (var package_index = 0; package_index < app.config.packages.length; package_index++) {
-        var current_package = app.config.packages[package_index]
+      for (let package_index = 0; package_index < app.config.packages.length; package_index++) {
+        const current_package = app.config.packages[package_index]
         if (current_package.default != null) {
           results[current_package.name] = current_package.default
         }
@@ -57,7 +57,7 @@ export default {
         results.mode = 'force'
       }
 
-      var targetUrl = '/api/start-install'
+      let targetUrl = '/api/start-install'
       if (this.is_uninstall) {
         targetUrl = '/api/uninstall'
       }

ui/src/views/SelectPackages.vue

@@ -116,9 +116,9 @@ export default {
         this.$router.push('/install/regular')
         return
       }
-      var my = this
+      const my = this
       this.$http.post('/api/verify-path', `path=${this.$root.$data.install_location}`).then(function (resp) {
-        var data = resp.data || {}
+        const data = resp.data || {}
         if (!data.exists) {
           my.$router.push('/install/regular')
         } else {