diff --git a/src/ui/public/StackTraceMapper/SourceMapReader.js b/src/ui/public/StackTraceMapper/SourceMapReader.js
index 122a89317d697..7bbabefcb36b9 100644
--- a/src/ui/public/StackTraceMapper/SourceMapReader.js
+++ b/src/ui/public/StackTraceMapper/SourceMapReader.js
@@ -1,6 +1,6 @@
-var _ = require('lodash');
-var SourceMapConsumer = require('source-map/lib/source-map/source-map-consumer').SourceMapConsumer;
-var parse = require('url').parse;
+let _ = require('lodash');
+let SourceMapConsumer = require('source-map/lib/source-map/source-map-consumer').SourceMapConsumer;
+let parse = require('url').parse;
 
 function SourceMapReader(url, map) {
   this.smc = new SourceMapConsumer(map);
diff --git a/src/ui/public/StackTraceMapper/StackTraceMapper.js b/src/ui/public/StackTraceMapper/StackTraceMapper.js
index 0324e1b13aa45..85cdad2a3eed3 100644
--- a/src/ui/public/StackTraceMapper/StackTraceMapper.js
+++ b/src/ui/public/StackTraceMapper/StackTraceMapper.js
@@ -1,12 +1,12 @@
-var _ = require('lodash');
-var $ = require('jquery');
-var resolve = require('bluebird').resolve;
-var fetch = require('exports?window.fetch!imports?Promise=bluebird!whatwg-fetch');
+let _ = require('lodash');
+let $ = require('jquery');
+let resolve = require('bluebird').resolve;
+let fetch = require('exports?window.fetch!imports?Promise=bluebird!whatwg-fetch');
 
-var setErrorStack = require('./setErrorStack');
-var translateStackLine = require('./translateStackLine');
-var stackLineFormat = require('./stackLineFormat');
-var SourceMapReader = require('./SourceMapReader');
+let setErrorStack = require('./setErrorStack');
+let translateStackLine = require('./translateStackLine');
+let stackLineFormat = require('./stackLineFormat');
+let SourceMapReader = require('./SourceMapReader');
 
 function StackTraceMapper() {
   this.maps = [];
@@ -22,7 +22,7 @@ StackTraceMapper.prototype.init = function (mapUrls) {
 StackTraceMapper.prototype.mapError = function (err) {
   if (!stackLineFormat || !err.stack) return err;
 
-  var stack = err.stack.replace(stackLineFormat, this.mapLine);
+  let stack = err.stack.replace(stackLineFormat, this.mapLine);
   return setErrorStack(err, stack);
 };
 
@@ -39,10 +39,10 @@ StackTraceMapper.prototype.getMapFor = function (url) {
 StackTraceMapper.prototype.loadMaps = function (mapUrls) {
   mapUrls = _.clone(mapUrls || {});
 
-  var maps = this.maps;
+  let maps = this.maps;
 
   $('script[src][src-map]').each(function () {
-    var $el = $(this);
+    let $el = $(this);
     mapUrls[$el.attr('src')] = $el.attr('src-map');
   });
 
diff --git a/src/ui/public/StackTraceMapper/setErrorStack.js b/src/ui/public/StackTraceMapper/setErrorStack.js
index 5ae5e0b553535..eb28b408d5c26 100644
--- a/src/ui/public/StackTraceMapper/setErrorStack.js
+++ b/src/ui/public/StackTraceMapper/setErrorStack.js
@@ -1,6 +1,6 @@
-var _ = require('lodash');
+let _ = require('lodash');
 
-var err = new Error();
+let err = new Error();
 try { setByAssignment(err, 'john'); } catch (e) {} // eslint-disable-line
 
 // err.stack is not always writeable, so we
@@ -13,7 +13,7 @@ if (err.stack === 'john') module.exports = setByAssignment;
 else module.exports = setByShadowing;
 
 function setByShadowing(err, stack) {
-  var props = _.mapValues(err, function (val) {
+  let props = _.mapValues(err, function (val) {
     return {
       enumerable: true,
       value: val
diff --git a/src/ui/public/StackTraceMapper/stackLineFormat.js b/src/ui/public/StackTraceMapper/stackLineFormat.js
index 07bde99b5a803..a571a50219398 100644
--- a/src/ui/public/StackTraceMapper/stackLineFormat.js
+++ b/src/ui/public/StackTraceMapper/stackLineFormat.js
@@ -1,6 +1,6 @@
-var _ = require('lodash');
+let _ = require('lodash');
 
-var opts = [
+let opts = [
   /@((?:[!#$&-;=?-\[\]_a-z~]|%[0-9a-f]{2})+\.js)\:(\d+)(?:\:(\d+)|())/ig,
   /(?: \(|at )((?:[!#$&-;=?-\[\]_a-z~]|%[0-9a-f]{2})+\.js)\:(\d+)(?:\:(\d+)|())/ig
 ];
@@ -8,7 +8,7 @@ var opts = [
 let sample;
 try { throw new Error('msg'); } catch (e) { sample = e.stack; }
 
-var format = _.find(opts, function (format) {
+let format = _.find(opts, function (format) {
   return format.test(sample);
 });
 
diff --git a/src/ui/public/StackTraceMapper/translateStackLine.js b/src/ui/public/StackTraceMapper/translateStackLine.js
index de6eae6347b03..f9983daade78a 100644
--- a/src/ui/public/StackTraceMapper/translateStackLine.js
+++ b/src/ui/public/StackTraceMapper/translateStackLine.js
@@ -1,19 +1,19 @@
-var _ = require('lodash');
+let _ = require('lodash');
 
 module.exports = function (map, match, filename, line, col) {
   if (!map) return match;
 
-  var position = {
+  let position = {
     line: parseFloat(line) || 0,
     column: parseFloat(col) || 0
   };
 
-  var srcPosition = map.smc.originalPositionFor(position);
+  let srcPosition = map.smc.originalPositionFor(position);
   if (!srcPosition || !srcPosition.source) return match;
 
-  var srcFilename = srcPosition.source;
-  var srcLine = srcPosition.line;
-  var srcCol = srcPosition.column;
+  let srcFilename = srcPosition.source;
+  let srcLine = srcPosition.line;
+  let srcCol = srcPosition.column;
 
   if (srcCol === 0 && position.column) {
     // TODO: teach sourcemaps correct column
@@ -26,10 +26,10 @@ module.exports = function (map, match, filename, line, col) {
   // fold the components into the original match, so that supporting
   // characters (parens, periods, etc) from the format are kept, and so
   // we don't accidentally replace the wrong part we use splitting and consumption
-  var resp = '';
-  var remainingResp = match;
-  var fold = function (replace, replacement) {
-    var wrappingContent = remainingResp.split(replace);
+  let resp = '';
+  let remainingResp = match;
+  let fold = function (replace, replacement) {
+    let wrappingContent = remainingResp.split(replace);
     resp += wrappingContent.shift() + replacement;
     remainingResp = wrappingContent.join(replace);
   };
diff --git a/src/ui/public/paginated_table/paginated_table.js b/src/ui/public/paginated_table/paginated_table.js
index 5d14609a72e84..8845f7260242b 100644
--- a/src/ui/public/paginated_table/paginated_table.js
+++ b/src/ui/public/paginated_table/paginated_table.js
@@ -2,8 +2,8 @@ define(function (require) {
   require('ui/modules')
   .get('kibana')
   .directive('paginatedTable', function ($filter) {
-    var _ = require('lodash');
-    var orderBy = $filter('orderBy');
+    let _ = require('lodash');
+    let orderBy = $filter('orderBy');
 
     return {
       restrict: 'E',
@@ -18,14 +18,14 @@ define(function (require) {
       },
       controllerAs: 'paginatedTable',
       controller: function ($scope) {
-        var self = this;
+        let self = this;
         self.sort = {
           columnIndex: null,
           direction: null
         };
 
         self.sortColumn = function (colIndex) {
-          var col = $scope.columns[colIndex];
+          let col = $scope.columns[colIndex];
 
           if (!col) return;
           if (col.sortable === false) return;
@@ -35,7 +35,7 @@ define(function (require) {
           if (self.sort.columnIndex !== colIndex) {
             sortDirection = 'asc';
           } else {
-            var directions = {
+            let directions = {
               null: 'asc',
               'asc': 'desc',
               'desc': null
@@ -55,7 +55,7 @@ define(function (require) {
           } else {
             // use generic sort handler
             self.sort.getter = function (row) {
-              var value = row[index];
+              let value = row[index];
               if (value && value.value != null) return value.value;
               return value;
             };
@@ -73,7 +73,7 @@ define(function (require) {
             return;
           }
 
-          var sort = self.sort;
+          let sort = self.sort;
           if (sort.direction == null) {
             $scope.sortedRows = $scope.rows.slice(0);
           } else {
diff --git a/src/ui/public/parse_query/lib/from_user.js b/src/ui/public/parse_query/lib/from_user.js
index 0eb2e32d93efd..6792494ab4e27 100644
--- a/src/ui/public/parse_query/lib/from_user.js
+++ b/src/ui/public/parse_query/lib/from_user.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  var _ = require('lodash');
+  let _ = require('lodash');
   return function GetQueryFromUser(es, Private) {
-    var decorateQuery = Private(require('ui/courier/data_source/_decorate_query'));
+    let decorateQuery = Private(require('ui/courier/data_source/_decorate_query'));
 
     /**
      * Take text from the user and make it into a query object
@@ -13,7 +13,7 @@ define(function (require) {
         return decorateQuery({query_string: {query: text}});
       }
 
-      var matchAll = getQueryStringQuery('*');
+      let matchAll = getQueryStringQuery('*');
 
       // If we get an empty object, treat it as a *
       if (_.isObject(text)) {
diff --git a/src/ui/public/parse_query/lib/to_user.js b/src/ui/public/parse_query/lib/to_user.js
index 736718a5d0d01..9eef6e8a4b8bc 100644
--- a/src/ui/public/parse_query/lib/to_user.js
+++ b/src/ui/public/parse_query/lib/to_user.js
@@ -1,6 +1,6 @@
 define(function (require) {
-  var _ = require('lodash');
-  var angular = require('angular');
+  let _ = require('lodash');
+  let angular = require('angular');
 
   /**
    * Take text from the model and present it to the user as a string
diff --git a/src/ui/public/parse_query/parse_query.js b/src/ui/public/parse_query/parse_query.js
index b14384e507ff1..a17dfd772c17c 100644
--- a/src/ui/public/parse_query/parse_query.js
+++ b/src/ui/public/parse_query/parse_query.js
@@ -2,8 +2,8 @@ define(function (require) {
   require('ui/modules')
     .get('kibana')
     .directive('parseQuery', function (Private) {
-      var fromUser = Private(require('ui/parse_query/lib/from_user'));
-      var toUser = require('ui/parse_query/lib/to_user');
+      let fromUser = Private(require('ui/parse_query/lib/from_user'));
+      let toUser = require('ui/parse_query/lib/to_user');
 
       return {
         restrict: 'A',
@@ -12,7 +12,7 @@ define(function (require) {
           'ngModel': '='
         },
         link: function ($scope, elem, attr, ngModel) {
-          var init = function () {
+          let init = function () {
             $scope.ngModel = fromUser($scope.ngModel);
           };
 
diff --git a/src/ui/public/persisted_log/persisted_log.js b/src/ui/public/persisted_log/persisted_log.js
index dfcb3c793c4a7..e3b4fff263a02 100644
--- a/src/ui/public/persisted_log/persisted_log.js
+++ b/src/ui/public/persisted_log/persisted_log.js
@@ -1,6 +1,6 @@
 define(function (require) {
-  var modules = require('ui/modules');
-  var _ = require('lodash');
+  let modules = require('ui/modules');
+  let _ = require('lodash');
 
   modules.get('kibana/persisted_log')
   .factory('PersistedLog', function ($window, localStorage) {
diff --git a/src/ui/public/persisted_state/persisted_state.js b/src/ui/public/persisted_state/persisted_state.js
index cf4f2bbda9360..9bf400c21c000 100644
--- a/src/ui/public/persisted_state/persisted_state.js
+++ b/src/ui/public/persisted_state/persisted_state.js
@@ -1,11 +1,11 @@
 define(function (require) {
-  var _ = require('lodash');
-  var toPath = require('lodash/internal/toPath');
-  var errors = require('ui/errors');
+  let _ = require('lodash');
+  let toPath = require('lodash/internal/toPath');
+  let errors = require('ui/errors');
 
   return function (Private) {
-    var Events = Private(require('ui/events'));
-    var SimpleEmitter = require('ui/utils/SimpleEmitter');
+    let Events = Private(require('ui/events'));
+    let SimpleEmitter = require('ui/utils/SimpleEmitter');
 
     function validateParent(parent, path) {
       if (path.length <= 0) {
@@ -17,7 +17,7 @@ define(function (require) {
     }
 
     function validateValue(value) {
-      var msg = 'State value must be a plain object';
+      let msg = 'State value must be a plain object';
       if (!value) return;
       if (!_.isPlainObject(value)) throw new errors.PersistedStateError(msg);
     }
@@ -73,21 +73,21 @@ define(function (require) {
     };
 
     PersistedState.prototype.set = function (key, value) {
-      var params = prepSetParams(key, value, this._path);
-      var val = this._set(params.key, params.value);
+      let params = prepSetParams(key, value, this._path);
+      let val = this._set(params.key, params.value);
       this.emit('set');
       return val;
     };
 
     PersistedState.prototype.setSilent = function (key, value) {
-      var params = prepSetParams(key, value, this._path);
+      let params = prepSetParams(key, value, this._path);
       return this._set(params.key, params.value, true);
     };
 
     PersistedState.prototype.reset = function (path) {
-      var keyPath = this._getIndex(path);
-      var origValue = _.get(this._defaultState, keyPath);
-      var currentValue = _.get(this._mergedState, keyPath);
+      let keyPath = this._getIndex(path);
+      let origValue = _.get(this._defaultState, keyPath);
+      let currentValue = _.get(this._mergedState, keyPath);
 
       if (_.isUndefined(origValue)) {
         this._cleanPath(path, this._mergedState);
@@ -108,7 +108,7 @@ define(function (require) {
     };
 
     PersistedState.prototype.removeChild = function (path) {
-      var origValue = _.get(this._defaultState, this._getIndex(path));
+      let origValue = _.get(this._defaultState, this._getIndex(path));
 
       if (_.isUndefined(origValue)) {
         this.reset(path);
@@ -139,19 +139,19 @@ define(function (require) {
     };
 
     PersistedState.prototype._getPartialIndex = function (key) {
-      var keyPath = this._getIndex(key);
+      let keyPath = this._getIndex(key);
       return keyPath.slice(this._path.length);
     };
 
     PersistedState.prototype._cleanPath = function (path, stateTree) {
-      var partialPath = this._getPartialIndex(path);
-      var remove = true;
+      let partialPath = this._getPartialIndex(path);
+      let remove = true;
 
       // recursively delete value tree, when no other keys exist
       while (partialPath.length > 0) {
-        var lastKey = partialPath.splice(partialPath.length - 1, 1)[0];
-        var statePath = this._path.concat(partialPath);
-        var stateVal = statePath.length > 0 ? _.get(stateTree, statePath) : stateTree;
+        let lastKey = partialPath.splice(partialPath.length - 1, 1)[0];
+        let statePath = this._path.concat(partialPath);
+        let stateVal = statePath.length > 0 ? _.get(stateTree, statePath) : stateTree;
 
         // if stateVal isn't an object, do nothing
         if (!_.isPlainObject(stateVal)) return;
@@ -162,13 +162,13 @@ define(function (require) {
     };
 
     PersistedState.prototype._getDefault = function () {
-      var def = (this._hasPath()) ? undefined : {};
+      let def = (this._hasPath()) ? undefined : {};
       return (this._parent ? this.get() : def);
     };
 
     PersistedState.prototype._setPath = function (path) {
-      var isString = _.isString(path);
-      var isArray = _.isArray(path);
+      let isString = _.isString(path);
+      let isArray = _.isArray(path);
 
       if (!isString && !isArray) return [];
       return (isString) ? [this._getIndex(path)] : path;
@@ -196,11 +196,11 @@ define(function (require) {
     };
 
     PersistedState.prototype._set = function (key, value, silent, initialChildState) {
-      var self = this;
-      var stateChanged = false;
-      var initialState = !this._initialized;
-      var keyPath = this._getIndex(key);
-      var hasKeyPath = keyPath.length > 0;
+      let self = this;
+      let stateChanged = false;
+      let initialState = !this._initialized;
+      let keyPath = this._getIndex(key);
+      let hasKeyPath = keyPath.length > 0;
 
       // if this is the initial state value, save value as the default
       if (initialState) {
@@ -226,7 +226,7 @@ define(function (require) {
           }
         } else {
           // check for changes at path, emit an event when different
-          var curVal = hasKeyPath ? this.get(keyPath) : this._mergedState;
+          let curVal = hasKeyPath ? this.get(keyPath) : this._mergedState;
           stateChanged = !_.isEqual(curVal, value);
 
           if (!initialChildState) {
@@ -243,11 +243,11 @@ define(function (require) {
       }
 
       // update the merged state value
-      var targetObj = this._mergedState || _.cloneDeep(this._defaultState);
-      var sourceObj = _.merge({}, this._defaultChildState, this._changedState);
+      let targetObj = this._mergedState || _.cloneDeep(this._defaultState);
+      let sourceObj = _.merge({}, this._defaultChildState, this._changedState);
 
       // handler arguments are (targetValue, sourceValue, key, target, source)
-      var mergeMethod = function (targetValue, sourceValue, mergeKey) {
+      let mergeMethod = function (targetValue, sourceValue, mergeKey) {
         // if not initial state, skip default merge method (ie. return value, see note below)
         if (!initialState && !initialChildState && _.isEqual(keyPath, self._getIndex(mergeKey))) {
           // use the sourceValue or fall back to targetValue
diff --git a/src/ui/public/private/private.js b/src/ui/public/private/private.js
index 8d2f29f9056d7..0eebd7d2443c7 100644
--- a/src/ui/public/private/private.js
+++ b/src/ui/public/private/private.js
@@ -22,10 +22,10 @@ define(function (require) {
    * ```js
    * define(function (require) {
    *   return function ServerHealthProvider(Private, Promise) {
-   *     var ping = Private(require('ui/ping'));
+   *     let ping = Private(require('ui/ping'));
    *     return {
    *       check: Promise.method(function () {
-   *         var attempts = 0;
+   *         let attempts = 0;
    *         return (function attempt() {
    *           attempts += 1;
    *           return ping.ping()
@@ -86,8 +86,8 @@ define(function (require) {
    */
 
 
-  var _ = require('lodash');
-  var nextId = _.partial(_.uniqueId, 'privateProvider#');
+  let _ = require('lodash');
+  let nextId = _.partial(_.uniqueId, 'privateProvider#');
 
   function name(fn) {
     return fn.name || fn.toString().split('\n').shift();
@@ -95,11 +95,11 @@ define(function (require) {
 
   require('ui/modules').get('kibana')
   .provider('Private', function () {
-    var provider = this;
+    let provider = this;
 
     // one cache/swaps per Provider
-    var cache = {};
-    var swaps = {};
+    let cache = {};
+    let swaps = {};
 
     // return the uniq id for this function
     function identify(fn) {
@@ -117,15 +117,15 @@ define(function (require) {
     };
 
     provider.swap = function (fn, prov) {
-      var id = identify(fn);
+      let id = identify(fn);
       swaps[id] = prov;
     };
 
     provider.$get = ['$injector', function PrivateFactory($injector) {
 
       // prevent circular deps by tracking where we came from
-      var privPath = [];
-      var pathToString = function () {
+      let privPath = [];
+      let pathToString = function () {
         return privPath.map(name).join(' -> ');
       };
 
@@ -140,8 +140,8 @@ define(function (require) {
 
         privPath.push(prov);
 
-        var context = {};
-        var instance = $injector.invoke(prov, context, locals);
+        let context = {};
+        let instance = $injector.invoke(prov, context, locals);
         if (!_.isObject(instance)) instance = context;
 
         privPath.pop();
@@ -167,7 +167,7 @@ define(function (require) {
 
       // main api, get the appropriate instance for a provider
       function Private(prov) {
-        var id = identify(prov);
+        let id = identify(prov);
         let $delegateId;
         let $delegateProv;
 
diff --git a/src/ui/public/promises/promises.js b/src/ui/public/promises/promises.js
index a2407d1e0cf82..1f1651b913081 100644
--- a/src/ui/public/promises/promises.js
+++ b/src/ui/public/promises/promises.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  var _ = require('lodash');
+  let _ = require('lodash');
 
-  var module = require('ui/modules').get('kibana');
+  let module = require('ui/modules').get('kibana');
 
   // Provides a tiny subset of the excelent API from
   // bluebird, reimplemented using the $q service
@@ -9,7 +9,7 @@ define(function (require) {
     function Promise(fn) {
       if (typeof this === 'undefined') throw new Error('Promise constructor must be called with "new"');
 
-      var defer = $q.defer();
+      let defer = $q.defer();
       try {
         fn(defer.resolve, defer.reject);
       } catch (e) {
@@ -20,12 +20,12 @@ define(function (require) {
 
     Promise.all = Promise.props = $q.all;
     Promise.resolve = function (val) {
-      var defer = $q.defer();
+      let defer = $q.defer();
       defer.resolve(val);
       return defer.promise;
     };
     Promise.reject = function (reason) {
-      var defer = $q.defer();
+      let defer = $q.defer();
       defer.reject(reason);
       return defer.promise;
     };
@@ -36,7 +36,7 @@ define(function (require) {
     };
     Promise.method = function (fn) {
       return function () {
-        var args = Array.prototype.slice.call(arguments);
+        let args = Array.prototype.slice.call(arguments);
         return Promise.try(fn, args, this);
       };
     };
@@ -64,7 +64,7 @@ define(function (require) {
       return obj && typeof obj.then === 'function';
     };
     Promise.halt = _.once(function () {
-      var promise = new Promise();
+      let promise = new Promise();
       promise.then = _.constant(promise);
       promise.catch = _.constant(promise);
       return promise;
@@ -155,7 +155,7 @@ define(function (require) {
      * @return {Promise}
      */
     function PromiseEmitter(fn, handler) {
-      var prom = new Promise(fn);
+      let prom = new Promise(fn);
 
       if (!handler) return prom;
 
diff --git a/src/ui/public/reflow_watcher/reflow_watcher.js b/src/ui/public/reflow_watcher/reflow_watcher.js
index d6aad9a2649cb..c4128f3d0db59 100644
--- a/src/ui/public/reflow_watcher/reflow_watcher.js
+++ b/src/ui/public/reflow_watcher/reflow_watcher.js
@@ -1,15 +1,15 @@
 define(function (require) {
   return function ReflowWatcherService(Private, $rootScope, $http) {
-    var angular = require('angular');
-    var $ = require('jquery');
-    var _ = require('lodash');
+    let angular = require('angular');
+    let $ = require('jquery');
+    let _ = require('lodash');
 
-    var EventEmitter = Private(require('ui/events'));
-    var $body = $(document.body);
-    var $window = $(window);
+    let EventEmitter = Private(require('ui/events'));
+    let $body = $(document.body);
+    let $window = $(window);
 
-    var MOUSE_EVENTS = 'mouseup';
-    var WINDOW_EVENTS = 'resize';
+    let MOUSE_EVENTS = 'mouseup';
+    let WINDOW_EVENTS = 'resize';
 
     _.class(ReflowWatcher).inherits(EventEmitter);
     /**
diff --git a/src/ui/public/registry/_registry.js b/src/ui/public/registry/_registry.js
index 4530e93249afe..a3ff35905c93f 100644
--- a/src/ui/public/registry/_registry.js
+++ b/src/ui/public/registry/_registry.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  var _ = require('lodash');
-  var IndexedArray = require('ui/IndexedArray');
-  var notPropsOptNames = IndexedArray.OPT_NAMES.concat('constructor');
+  let _ = require('lodash');
+  let IndexedArray = require('ui/IndexedArray');
+  let notPropsOptNames = IndexedArray.OPT_NAMES.concat('constructor');
 
   /**
    * Create a registry, which is just a Private module provider.
@@ -16,7 +16,7 @@ define(function (require) {
    *
    * + register a module
    * ```js
-   * var registry = require('ui/registry/vis_types');
+   * let registry = require('ui/registry/vis_types');
    * registry.add(function InjectablePrivateModule($http, Promise) {
    *   ...
    * })
@@ -24,7 +24,7 @@ define(function (require) {
    *
    * + get all registered modules
    * ```js
-   * var visTypes = Private(require('ui/registry/vis_types'));
+   * let visTypes = Private(require('ui/registry/vis_types'));
    * ```
    *
    *
@@ -49,10 +49,10 @@ define(function (require) {
   return function createRegistry(spec) {
     spec = spec || {};
 
-    var constructor = _.has(spec, 'constructor') && spec.constructor;
-    var iaOpts = _.defaults(_.pick(spec, IndexedArray.OPT_NAMES), { index: ['name'] });
-    var props = _.omit(spec, notPropsOptNames);
-    var providers = [];
+    let constructor = _.has(spec, 'constructor') && spec.constructor;
+    let iaOpts = _.defaults(_.pick(spec, IndexedArray.OPT_NAMES), { index: ['name'] });
+    let props = _.omit(spec, notPropsOptNames);
+    let providers = [];
 
     /**
      * This is the Private module that will be instanciated by
@@ -62,10 +62,10 @@ define(function (require) {
      *                          that were registered, the registry spec
      *                          defines how things will be indexed.
      */
-    var registry = function (Private, $injector) {
+    let registry = function (Private, $injector) {
       // index all of the modules
       iaOpts.initialSet = providers.map(Private);
-      var modules = new IndexedArray(iaOpts);
+      let modules = new IndexedArray(iaOpts);
 
       // mixin other props
       _.assign(modules, props);
diff --git a/src/ui/public/registry/field_formats.js b/src/ui/public/registry/field_formats.js
index 4eb93526f0321..8d37db7d99254 100644
--- a/src/ui/public/registry/field_formats.js
+++ b/src/ui/public/registry/field_formats.js
@@ -1,5 +1,5 @@
 define(function (require) {
-  var _ = require('lodash');
+  let _ = require('lodash');
 
   return require('ui/registry/_registry')({
     name: 'fieldFormats',
@@ -7,7 +7,7 @@ define(function (require) {
     group: ['fieldType'],
 
     constructor: function (config, $rootScope) {
-      var self = this;
+      let self = this;
       let defaultMap;
 
       function init() {
@@ -56,7 +56,7 @@ define(function (require) {
        * @return {FieldFormat}
        */
       self.getInstance = _.memoize(function (formatId) {
-        var FieldFormat = self.byId[formatId];
+        let FieldFormat = self.byId[formatId];
         return new FieldFormat();
       });
 
@@ -67,8 +67,8 @@ define(function (require) {
        * @return {FieldFormat}
        */
       self.getDefaultInstance = _.memoize(function (fieldType) {
-        var conf = self.getDefaultConfig(fieldType);
-        var FieldFormat = self.byId[conf.id];
+        let conf = self.getDefaultConfig(fieldType);
+        let FieldFormat = self.byId[conf.id];
         return new FieldFormat(conf.params);
       });
 
diff --git a/src/ui/public/routes/RouteManager.js b/src/ui/public/routes/RouteManager.js
index 2b77fd843fead..24425c933db0d 100644
--- a/src/ui/public/routes/RouteManager.js
+++ b/src/ui/public/routes/RouteManager.js
@@ -1,19 +1,19 @@
-var _ = require('lodash');
+let _ = require('lodash');
 
-var wrapRouteWithPrep = require('./wrapRouteWithPrep');
-var RouteSetupManager = require('./RouteSetupManager');
+let wrapRouteWithPrep = require('./wrapRouteWithPrep');
+let RouteSetupManager = require('./RouteSetupManager');
 
 function RouteManager() {
-  var self = this;
-  var setup = new RouteSetupManager();
-  var when = [];
-  var defaults = [];
+  let self = this;
+  let setup = new RouteSetupManager();
+  let when = [];
+  let defaults = [];
   let otherwise;
 
   self.config = function ($routeProvider) {
     when.forEach(function (args) {
-      var path = args[0];
-      var route = args[1] || {};
+      let path = args[0];
+      let route = args[1] || {};
 
       // merge in any defaults
       defaults.forEach(function (args) {
diff --git a/src/ui/public/routes/RouteSetupManager.js b/src/ui/public/routes/RouteSetupManager.js
index a2fd67b6e40df..1fb7b5399c565 100644
--- a/src/ui/public/routes/RouteSetupManager.js
+++ b/src/ui/public/routes/RouteSetupManager.js
@@ -66,7 +66,7 @@ module.exports = class RouteSetupManager {
     )
     .then(() => {
       // wait for the queue to fill up, then do all the work
-      var defer = Promise.defer();
+      let defer = Promise.defer();
       userWork.resolveWhenFull(defer);
 
       return defer.promise.then(() => Promise.all(userWork.doWork()));
diff --git a/src/ui/public/routes/WorkQueue.js b/src/ui/public/routes/WorkQueue.js
index 79536fbd23218..73e41b94df394 100644
--- a/src/ui/public/routes/WorkQueue.js
+++ b/src/ui/public/routes/WorkQueue.js
@@ -1,11 +1,11 @@
 define(function (require) {
-  var _ = require('lodash');
+  let _ = require('lodash');
 
   function WorkQueue() {
-    var q = this;
+    let q = this;
 
-    var work = [];
-    var fullDefers = [];
+    let work = [];
+    let fullDefers = [];
 
     q.limit = 0;
     Object.defineProperty(q, 'length', {
@@ -14,13 +14,13 @@ define(function (require) {
       }
     });
 
-    var resolve = function (defers) {
+    let resolve = function (defers) {
       return defers.splice(0).map(function (defer) {
         return defer.resolve();
       });
     };
 
-    var checkIfFull = function () {
+    let checkIfFull = function () {
       if (work.length >= q.limit && fullDefers.length) {
         resolve(fullDefers);
       }
@@ -32,7 +32,7 @@ define(function (require) {
     };
 
     q.doWork = function () {
-      var resps = resolve(work);
+      let resps = resolve(work);
       checkIfFull();
       return resps;
     };
diff --git a/src/ui/public/routes/routes.js b/src/ui/public/routes/routes.js
index fde6cc637e98d..58b26aa14be26 100644
--- a/src/ui/public/routes/routes.js
+++ b/src/ui/public/routes/routes.js
@@ -1,5 +1,5 @@
-var RouteManager = require('./RouteManager');
-var defaultRouteManager = new RouteManager();
+let RouteManager = require('./RouteManager');
+let defaultRouteManager = new RouteManager();
 
 module.exports = {
   ...defaultRouteManager,
diff --git a/src/ui/public/routes/wrapRouteWithPrep.js b/src/ui/public/routes/wrapRouteWithPrep.js
index e92b50018e872..3c266d1c44c2e 100644
--- a/src/ui/public/routes/wrapRouteWithPrep.js
+++ b/src/ui/public/routes/wrapRouteWithPrep.js
@@ -1,18 +1,18 @@
 define(function (require) {
-  var angular = require('angular');
-  var _ = require('lodash');
+  let angular = require('angular');
+  let _ = require('lodash');
 
-  var WorkQueue = require('ui/routes/WorkQueue');
-  var errors = require('ui/errors');
+  let WorkQueue = require('ui/routes/WorkQueue');
+  let errors = require('ui/errors');
 
   function wrapRouteWithPrep(route, setup) {
     if (!route.resolve && route.redirectTo) return;
 
-    var userWork = new WorkQueue();
+    let userWork = new WorkQueue();
     // the point at which we will consider the queue "full"
     userWork.limit = _.keys(route.resolve).length;
 
-    var resolve = {
+    let resolve = {
       __prep__: function ($injector) {
         return $injector.invoke(setup.doWork, setup, { userWork });
       }
@@ -22,7 +22,7 @@ define(function (require) {
     // prep is complete
     _.forOwn(route.resolve || {}, function (expr, name) {
       resolve[name] = function ($injector, Promise) {
-        var defer = Promise.defer();
+        let defer = Promise.defer();
         userWork.push(defer);
         return defer.promise.then(function () {
           return $injector[angular.isString(expr) ? 'get' : 'invoke'](expr);
diff --git a/src/ui/public/state_management/_state_sync.js b/src/ui/public/state_management/_state_sync.js
index 7c4925eb17cae..f23dc183d6bad 100644
--- a/src/ui/public/state_management/_state_sync.js
+++ b/src/ui/public/state_management/_state_sync.js
@@ -1,15 +1,15 @@
 define(function (require) {
 
-  var angular = require('angular');
-  var _ = require('lodash');
-  var rison = require('ui/utils/rison');
+  let angular = require('angular');
+  let _ = require('lodash');
+  let rison = require('ui/utils/rison');
 
   // invokable/private angular dep
   return function ($location) {
     // feed in some of the private state from globalState
     return function (globalState, updateListeners, app) {
-      var getAppStash = function (search) {
-        var appStash = search._a && rison.decode(search._a);
+      let getAppStash = function (search) {
+        let appStash = search._a && rison.decode(search._a);
         if (app.current) {
           // Apply the defaults to appStash
           appStash = _.defaults(appStash || {}, app.defaults);
@@ -17,20 +17,20 @@ define(function (require) {
         return appStash;
       };
 
-      var diffTrans = function (trans) {
-        var obj = trans[0];
-        var update = trans[1];
+      let diffTrans = function (trans) {
+        let obj = trans[0];
+        let update = trans[1];
 
-        var diff = {};
+        let diff = {};
 
         // the keys that are currently set on obj, excluding methods
-        var objKeys = Object.keys(obj).filter(function (key) {
+        let objKeys = Object.keys(obj).filter(function (key) {
           return typeof obj[key] !== 'function';
         });
 
         if (update) {
           // the keys obj should have after applying the update
-          var updateKeys = diff.keys = Object.keys(update).filter(function (key) {
+          let updateKeys = diff.keys = Object.keys(update).filter(function (key) {
             return typeof update[key] !== 'function';
           });
 
@@ -53,8 +53,8 @@ define(function (require) {
         return diff;
       };
 
-      var notify = function (trans, diff) {
-        var listeners = null;
+      let notify = function (trans, diff) {
+        let listeners = null;
 
         if (trans[0] === app.current) {
           listeners = app.listeners;
@@ -67,11 +67,11 @@ define(function (require) {
         });
       };
 
-      var applyDiff = function (trans, diff) {
+      let applyDiff = function (trans, diff) {
         if (!diff.all.length) return;
 
-        var obj = trans[0];
-        var update = trans[1];
+        let obj = trans[0];
+        let update = trans[1];
 
         diff.remove.forEach(function (key) {
           delete obj[key];
@@ -82,13 +82,13 @@ define(function (require) {
         });
       };
 
-      var syncTrans = function (trans, forceNotify) {
+      let syncTrans = function (trans, forceNotify) {
         // obj that will be modified by update(trans[1])
         // if it is empty, we can skip it all
-        var skipWrite = !trans[0];
+        let skipWrite = !trans[0];
         trans[0] = trans[0] || {};
 
-        var diff = diffTrans(trans);
+        let diff = diffTrans(trans);
         if (!skipWrite && (forceNotify || diff.all.length)) {
           applyDiff(trans, diff);
           notify(trans, diff);
@@ -99,17 +99,17 @@ define(function (require) {
       return {
         // sync by pushing to the url
         push: function (forceNotify) {
-          var search = $location.search();
+          let search = $location.search();
 
-          var appStash = getAppStash(search) || {};
-          var globalStash = search._g ? rison.decode(search._g) : {};
+          let appStash = getAppStash(search) || {};
+          let globalStash = search._g ? rison.decode(search._g) : {};
 
-          var res = _.mapValues({
+          let res = _.mapValues({
             app: [appStash, app.current],
             global: [globalStash, globalState]
           }, function (trans, key) {
-            var diff = syncTrans(trans, forceNotify);
-            var urlKey = '_' + key.charAt(0);
+            let diff = syncTrans(trans, forceNotify);
+            let urlKey = '_' + key.charAt(0);
             if (diff.keys.length === 0) {
               delete search[urlKey];
             } else {
@@ -123,10 +123,10 @@ define(function (require) {
         },
         // sync by pulling from the url
         pull: function (forceNotify) {
-          var search = $location.search();
+          let search = $location.search();
 
-          var appStash = getAppStash(search);
-          var globalStash = search._g && rison.decode(search._g);
+          let appStash = getAppStash(search);
+          let globalStash = search._g && rison.decode(search._g);
 
           return _.mapValues({
             app: [app.current, appStash],
diff --git a/src/ui/public/state_management/app_state.js b/src/ui/public/state_management/app_state.js
index 7a6ed5191c3e0..8bb6454d5d99e 100644
--- a/src/ui/public/state_management/app_state.js
+++ b/src/ui/public/state_management/app_state.js
@@ -1,11 +1,11 @@
 define(function (require) {
-  var _ = require('lodash');
-  var modules = require('ui/modules');
-  var urlParam = '_a';
+  let _ = require('lodash');
+  let modules = require('ui/modules');
+  let urlParam = '_a';
 
   function AppStateProvider(Private, $rootScope, getAppState) {
-    var State = Private(require('ui/state_management/state'));
-    var PersistedState = Private(require('ui/persisted_state/persisted_state'));
+    let State = Private(require('ui/state_management/state'));
+    let PersistedState = Private(require('ui/persisted_state/persisted_state'));
     let persistedStates;
     let eventUnsubscribers;
 
@@ -29,31 +29,31 @@ define(function (require) {
 
     AppState.prototype.makeStateful = function (prop) {
       if (persistedStates[prop]) return persistedStates[prop];
-      var self = this;
+      let self = this;
 
       // set up the ui state
       persistedStates[prop] = new PersistedState();
 
       // update the app state when the stateful instance changes
-      var updateOnChange = function () {
-        var replaceState = false; // TODO: debouncing logic
+      let updateOnChange = function () {
+        let replaceState = false; // TODO: debouncing logic
 
         self[prop] = persistedStates[prop].getChanges();
         self.save(replaceState);
       };
-      var handlerOnChange = (method) => persistedStates[prop][method]('change', updateOnChange);
+      let handlerOnChange = (method) => persistedStates[prop][method]('change', updateOnChange);
       handlerOnChange('on');
       eventUnsubscribers.push(() => handlerOnChange('off'));
 
       // update the stateful object when the app state changes
-      var persistOnChange = function (changes) {
+      let persistOnChange = function (changes) {
         if (!changes) return;
 
         if (changes.indexOf(prop) !== -1) {
           persistedStates[prop].set(self[prop]);
         }
       };
-      var handlePersist = (method) => this[method]('fetch_with_changes', persistOnChange);
+      let handlePersist = (method) => this[method]('fetch_with_changes', persistOnChange);
       handlePersist('on');
       eventUnsubscribers.push(() => handlePersist('off'));
 
@@ -79,7 +79,7 @@ define(function (require) {
 
     // Checks to see if the appState might already exist, even if it hasn't been newed up
     get.previouslyStored = function () {
-      var search = $location.search();
+      let search = $location.search();
       return search[urlParam] ? true : false;
     };
 
diff --git a/src/ui/public/state_management/global_state.js b/src/ui/public/state_management/global_state.js
index 6f74135ea4e8d..469b815b28bb3 100644
--- a/src/ui/public/state_management/global_state.js
+++ b/src/ui/public/state_management/global_state.js
@@ -1,13 +1,13 @@
 define(function (require) {
-  var _ = require('lodash');
-  var angular = require('angular');
-  var qs = require('ui/utils/query_string');
-  var rison = require('ui/utils/rison');
+  let _ = require('lodash');
+  let angular = require('angular');
+  let qs = require('ui/utils/query_string');
+  let rison = require('ui/utils/rison');
 
-  var module = require('ui/modules').get('kibana/global_state');
+  let module = require('ui/modules').get('kibana/global_state');
 
   module.service('globalState', function (Private, $rootScope, $location) {
-    var State = Private(require('ui/state_management/state'));
+    let State = Private(require('ui/state_management/state'));
 
     _.class(GlobalState).inherits(State);
     function GlobalState(defaults) {
diff --git a/src/ui/public/state_management/state.js b/src/ui/public/state_management/state.js
index 64e202d6e41ba..373639037ab99 100644
--- a/src/ui/public/state_management/state.js
+++ b/src/ui/public/state_management/state.js
@@ -1,18 +1,18 @@
 define(function (require) {
-  var _ = require('lodash');
-  var rison = require('ui/utils/rison');
+  let _ = require('lodash');
+  let rison = require('ui/utils/rison');
 
-  var applyDiff = require('ui/utils/diff_object');
-  var qs = require('ui/utils/query_string');
+  let applyDiff = require('ui/utils/diff_object');
+  let qs = require('ui/utils/query_string');
 
   return function StateProvider(Notifier, Private, $rootScope, $location) {
-    var Events = Private(require('ui/events'));
+    let Events = Private(require('ui/events'));
 
     _.class(State).inherits(Events);
     function State(urlParam, defaults) {
       State.Super.call(this);
 
-      var self = this;
+      let self = this;
       self.setDefaults(defaults);
       self._urlParam = urlParam || '_s';
 
@@ -39,11 +39,11 @@ define(function (require) {
     }
 
     State.prototype._readFromURL = function () {
-      var search = $location.search();
+      let search = $location.search();
       try {
         return search[this._urlParam] ? rison.decode(search[this._urlParam]) : null;
       } catch (e) {
-        var notify = new Notifier();
+        let notify = new Notifier();
         notify.error('Unable to parse URL');
         search[this._urlParam] = rison.encode(this._defaults);
         $location.search(search).replace();
@@ -56,7 +56,7 @@ define(function (require) {
      * @returns {void}
      */
     State.prototype.fetch = function () {
-      var stash = this._readFromURL();
+      let stash = this._readFromURL();
 
       // nothing to read from the url? save if ordered to persist
       if (stash === null) {
@@ -69,7 +69,7 @@ define(function (require) {
 
       _.defaults(stash, this._defaults);
       // apply diff to state from stash, will change state in place via side effect
-      var diffResults = applyDiff(this, stash);
+      let diffResults = applyDiff(this, stash);
 
       if (diffResults.keys.length) {
         this.emit('fetch_with_changes', diffResults.keys);
@@ -81,8 +81,8 @@ define(function (require) {
      * @returns {void}
      */
     State.prototype.save = function (replace) {
-      var stash = this._readFromURL();
-      var state = this.toObject();
+      let stash = this._readFromURL();
+      let state = this.toObject();
       replace = replace || false;
 
       if (!stash) {
@@ -92,14 +92,14 @@ define(function (require) {
 
       _.defaults(state, this._defaults);
       // apply diff to state from stash, will change state in place via side effect
-      var diffResults = applyDiff(stash, state);
+      let diffResults = applyDiff(stash, state);
 
       if (diffResults.keys.length) {
         this.emit('save_with_changes', diffResults.keys);
       }
 
       // persist the state in the URL
-      var search = $location.search();
+      let search = $location.search();
       search[this._urlParam] = this.toRISON();
       if (replace) {
         $location.search(search).replace();
@@ -124,7 +124,7 @@ define(function (require) {
     State.prototype.reset = function () {
       // apply diff to _attributes from defaults, this is side effecting so
       // it will change the state in place.
-      var diffResults = applyDiff(this, this._defaults);
+      let diffResults = applyDiff(this, this._defaults);
       if (diffResults.keys.length) {
         this.emit('reset_with_changes', diffResults.keys);
       }
diff --git a/src/ui/public/storage/storage.js b/src/ui/public/storage/storage.js
index 7207c66ea182a..cd7684afed9f8 100644
--- a/src/ui/public/storage/storage.js
+++ b/src/ui/public/storage/storage.js
@@ -1,9 +1,9 @@
 define(function (require) {
-  var modules = require('ui/modules');
-  var angular = require('angular');
+  let modules = require('ui/modules');
+  let angular = require('angular');
 
   function Storage(store) {
-    var self = this;
+    let self = this;
     self.store = store;
 
     self.get = function (key) {
@@ -31,7 +31,7 @@ define(function (require) {
     };
   }
 
-  var createService = function (type) {
+  let createService = function (type) {
     return function ($window) {
       return new Storage($window[type]);
     };
diff --git a/src/ui/public/stringify/register.js b/src/ui/public/stringify/register.js
index 7eddb1dd92783..1004a0c61ab63 100644
--- a/src/ui/public/stringify/register.js
+++ b/src/ui/public/stringify/register.js
@@ -1,5 +1,5 @@
 define(function (require) {
-  var fieldFormats = require('ui/registry/field_formats');
+  let fieldFormats = require('ui/registry/field_formats');
   fieldFormats.register(require('ui/stringify/types/Url'));
   fieldFormats.register(require('ui/stringify/types/Bytes'));
   fieldFormats.register(require('ui/stringify/types/Date'));
diff --git a/src/ui/public/stringify/types/Bytes.js b/src/ui/public/stringify/types/Bytes.js
index a164545ab08bb..74fa3585891ce 100644
--- a/src/ui/public/stringify/types/Bytes.js
+++ b/src/ui/public/stringify/types/Bytes.js
@@ -1,6 +1,6 @@
 define(function (require) {
   return function BytesFormatProvider(Private) {
-    var Numeral = Private(require('ui/stringify/types/_Numeral'));
+    let Numeral = Private(require('ui/stringify/types/_Numeral'));
     return Numeral.factory({
       id: 'bytes',
       title: 'Bytes',
diff --git a/src/ui/public/stringify/types/Date.js b/src/ui/public/stringify/types/Date.js
index bdd3ee463fc06..ce7fc3e28ae1e 100644
--- a/src/ui/public/stringify/types/Date.js
+++ b/src/ui/public/stringify/types/Date.js
@@ -1,9 +1,9 @@
 define(function (require) {
   return function DateTimeFormatProvider(Private) {
-    var _ = require('lodash');
-    var FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
-    var BoundToConfigObj = Private(require('ui/bound_to_config_obj'));
-    var moment = require('moment');
+    let _ = require('lodash');
+    let FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
+    let BoundToConfigObj = Private(require('ui/bound_to_config_obj'));
+    let moment = require('moment');
 
     require('ui/field_format_editor/pattern/pattern');
 
@@ -25,7 +25,7 @@ define(function (require) {
       template: require('ui/stringify/editors/date.html'),
       controllerAs: 'cntrl',
       controller: function ($interval, $scope) {
-        var self = this;
+        let self = this;
         self.sampleInputs = [
           Date.now(),
           +moment().startOf('year'),
@@ -41,11 +41,11 @@ define(function (require) {
     DateTime.prototype._convert = function (val) {
       // don't give away our ref to converter so
       // we can hot-swap when config changes
-      var pattern = this.param('pattern');
-      var timezone = this.param('timezone');
+      let pattern = this.param('pattern');
+      let timezone = this.param('timezone');
 
-      var timezoneChanged = this._timeZone !== timezone;
-      var datePatternChanged = this._memoizedPattern !== pattern;
+      let timezoneChanged = this._timeZone !== timezone;
+      let datePatternChanged = this._memoizedPattern !== pattern;
       if (timezoneChanged || datePatternChanged) {
         this._timeZone = timezone;
         this._memoizedPattern = pattern;
diff --git a/src/ui/public/stringify/types/Ip.js b/src/ui/public/stringify/types/Ip.js
index 29dbc6333afa0..2741d44dfcb83 100644
--- a/src/ui/public/stringify/types/Ip.js
+++ b/src/ui/public/stringify/types/Ip.js
@@ -1,7 +1,7 @@
 define(function (require) {
   return function IpFormatProvider(Private) {
-    var _ = require('lodash');
-    var FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
+    let _ = require('lodash');
+    let FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
 
     _.class(Ip).inherits(FieldFormat);
     function Ip(params) {
diff --git a/src/ui/public/stringify/types/Number.js b/src/ui/public/stringify/types/Number.js
index 84bb74d236234..66cec585b254d 100644
--- a/src/ui/public/stringify/types/Number.js
+++ b/src/ui/public/stringify/types/Number.js
@@ -1,6 +1,6 @@
 define(function (require) {
   return function NumberFormatProvider(Private) {
-    var Numeral = Private(require('ui/stringify/types/_Numeral'));
+    let Numeral = Private(require('ui/stringify/types/_Numeral'));
     return Numeral.factory({
       id: 'number',
       title: 'Number',
diff --git a/src/ui/public/stringify/types/Percent.js b/src/ui/public/stringify/types/Percent.js
index 093899fba6c77..689098b6478b5 100644
--- a/src/ui/public/stringify/types/Percent.js
+++ b/src/ui/public/stringify/types/Percent.js
@@ -1,8 +1,8 @@
 define(function (require) {
   return function NumberFormatProvider(Private) {
-    var _ = require('lodash');
-    var BoundToConfigObj = Private(require('ui/bound_to_config_obj'));
-    var Numeral = Private(require('ui/stringify/types/_Numeral'));
+    let _ = require('lodash');
+    let BoundToConfigObj = Private(require('ui/bound_to_config_obj'));
+    let Numeral = Private(require('ui/stringify/types/_Numeral'));
 
     return Numeral.factory({
       id: 'percent',
diff --git a/src/ui/public/stringify/types/Source.js b/src/ui/public/stringify/types/Source.js
index 20d778ec350fa..6a9cbd1951c16 100644
--- a/src/ui/public/stringify/types/Source.js
+++ b/src/ui/public/stringify/types/Source.js
@@ -1,10 +1,10 @@
 define(function (require) {
   return function _SourceProvider(Private, shortDotsFilter) {
-    var _ = require('lodash');
-    var FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
-    var noWhiteSpace = require('ui/utils/no_white_space');
-    var template = _.template(noWhiteSpace(require('ui/stringify/types/_source.html')));
-    var angular = require('angular');
+    let _ = require('lodash');
+    let FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
+    let noWhiteSpace = require('ui/utils/no_white_space');
+    let template = _.template(noWhiteSpace(require('ui/stringify/types/_source.html')));
+    let angular = require('angular');
 
     _.class(Source).inherits(FieldFormat);
     function Source(params) {
@@ -20,15 +20,15 @@ define(function (require) {
       html: function sourceToHtml(source, field, hit) {
         if (!field) return this.getConverter('text')(source, field, hit);
 
-        var highlights = (hit && hit.highlight) || {};
-        var formatted = field.indexPattern.formatHit(hit);
-        var highlightPairs = [];
-        var sourcePairs = [];
+        let highlights = (hit && hit.highlight) || {};
+        let formatted = field.indexPattern.formatHit(hit);
+        let highlightPairs = [];
+        let sourcePairs = [];
 
         _.keys(formatted).forEach(function (key) {
-          var pairs = highlights[key] ? highlightPairs : sourcePairs;
-          var field = shortDotsFilter(key);
-          var val = formatted[key];
+          let pairs = highlights[key] ? highlightPairs : sourcePairs;
+          let field = shortDotsFilter(key);
+          let val = formatted[key];
           pairs.push([field, val]);
         }, []);
 
diff --git a/src/ui/public/stringify/types/String.js b/src/ui/public/stringify/types/String.js
index 1d587474046f0..291be2ba21ae0 100644
--- a/src/ui/public/stringify/types/String.js
+++ b/src/ui/public/stringify/types/String.js
@@ -1,7 +1,7 @@
 define(function (require) {
   return function _StringProvider(Private) {
-    var _ = require('lodash');
-    var FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
+    let _ = require('lodash');
+    let FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
 
     require('ui/field_format_editor/samples/samples');
 
diff --git a/src/ui/public/stringify/types/Url.js b/src/ui/public/stringify/types/Url.js
index 53b29c00cbc36..9cb718808cb58 100644
--- a/src/ui/public/stringify/types/Url.js
+++ b/src/ui/public/stringify/types/Url.js
@@ -1,8 +1,8 @@
 define(function (require) {
   return function UrlFormatProvider(Private, highlightFilter) {
-    var _ = require('lodash');
+    let _ = require('lodash');
 
-    var FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
+    let FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
 
     require('ui/field_format_editor/pattern/pattern');
     require('ui/stringify/icons');
@@ -30,7 +30,7 @@ define(function (require) {
       template: require('ui/stringify/editors/url.html'),
       controllerAs: 'url',
       controller: function ($scope) {
-        var iconPattern = '/bundles/src/ui/public/stringify/icons/{{value}}.png';
+        let iconPattern = '/bundles/src/ui/public/stringify/icons/{{value}}.png';
 
         this.samples = {
           a: [ 'john', '/some/pathname/asset.png', 1234 ],
@@ -38,7 +38,7 @@ define(function (require) {
         };
 
         $scope.$watch('editor.formatParams.type', function (type, prev) {
-          var params = $scope.editor.formatParams;
+          let params = $scope.editor.formatParams;
           if (type === 'img' && type !== prev && !params.urlTemplate) {
             params.urlTemplate = iconPattern;
           }
@@ -59,7 +59,7 @@ define(function (require) {
     ];
 
     Url.prototype._formatUrl = function (value) {
-      var template = this.param('urlTemplate');
+      let template = this.param('urlTemplate');
       if (!template) return value;
 
       return this._compileTemplate(template)({
@@ -69,7 +69,7 @@ define(function (require) {
     };
 
     Url.prototype._formatLabel = function (value, url) {
-      var template = this.param('labelTemplate');
+      let template = this.param('labelTemplate');
       if (url == null) url = this._formatUrl(value);
       if (!template) return url;
 
@@ -85,8 +85,8 @@ define(function (require) {
       },
 
       html: function (rawValue, field, hit) {
-        var url = _.escape(this._formatUrl(rawValue));
-        var label = _.escape(this._formatLabel(rawValue, url));
+        let url = _.escape(this._formatUrl(rawValue));
+        let label = _.escape(this._formatLabel(rawValue, url));
 
         switch (this.param('type')) {
           case 'img':
@@ -102,19 +102,19 @@ define(function (require) {
     };
 
     Url.prototype._compileTemplate = function (template) {
-      var parts = template.split(Url.templateMatchRE).map(function (part, i) {
+      let parts = template.split(Url.templateMatchRE).map(function (part, i) {
         // trim all the odd bits, the variable names
         return (i % 2) ? part.trim() : part;
       });
 
       return function (locals) {
         // replace all the odd bits with their local var
-        var output = '';
-        var i = -1;
+        let output = '';
+        let i = -1;
         while (++i < parts.length) {
           if (i % 2) {
             if (locals.hasOwnProperty(parts[i])) {
-              var local = locals[parts[i]];
+              let local = locals[parts[i]];
               output += local == null ? '' : local;
             }
           } else {
diff --git a/src/ui/public/stringify/types/_Numeral.js b/src/ui/public/stringify/types/_Numeral.js
index 6c55a4616c5c3..ec99a625151c8 100644
--- a/src/ui/public/stringify/types/_Numeral.js
+++ b/src/ui/public/stringify/types/_Numeral.js
@@ -1,9 +1,9 @@
 define(function (require) {
   return function AbstractNumeralFormatProvider(Private) {
-    var _ = require('lodash');
-    var FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
-    var BoundToConfigObj = Private(require('ui/bound_to_config_obj'));
-    var numeral = require('numeral')();
+    let _ = require('lodash');
+    let FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
+    let BoundToConfigObj = Private(require('ui/bound_to_config_obj'));
+    let numeral = require('numeral')();
     require('ui/field_format_editor/numeral/numeral');
 
     _.class(Numeral).inherits(FieldFormat);
diff --git a/src/ui/public/stringify/types/truncate.js b/src/ui/public/stringify/types/truncate.js
index a461fadb7f863..8252cc708ddda 100644
--- a/src/ui/public/stringify/types/truncate.js
+++ b/src/ui/public/stringify/types/truncate.js
@@ -1,8 +1,8 @@
 define(function (require) {
   return function TruncateFormatProvider(Private) {
-    var _ = require('lodash');
-    var FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
-    var omission = '...';
+    let _ = require('lodash');
+    let FieldFormat = Private(require('ui/index_patterns/_field_format/FieldFormat'));
+    let omission = '...';
 
     _.class(Truncate).inherits(FieldFormat);
 
@@ -15,7 +15,7 @@ define(function (require) {
     Truncate.fieldType = ['string'];
 
     Truncate.prototype._convert = function (val) {
-      var length = this.param('fieldLength');
+      let length = this.param('fieldLength');
       if (length > 0) {
         return _.trunc(val, {
           'length': length + omission.length,
diff --git a/src/ui/public/styleCompile/styleCompile.js b/src/ui/public/styleCompile/styleCompile.js
index f318ec8e4b7c8..9050b674b51e3 100644
--- a/src/ui/public/styleCompile/styleCompile.js
+++ b/src/ui/public/styleCompile/styleCompile.js
@@ -1,16 +1,16 @@
 define(function (require) {
-  var _ = require('lodash');
-  var $ = require('jquery');
-  var $style = $('<style>').appendTo('head').attr('id', 'style-compile');
+  let _ = require('lodash');
+  let $ = require('jquery');
+  let $style = $('<style>').appendTo('head').attr('id', 'style-compile');
 
   require('ui/config');
 
   require('ui/modules')
   .get('kibana')
   .run(function ($rootScope, $compile, config) {
-    var truncateGradientHeight = 15;
-    var template = _.template(require('./styleCompile.css.tmpl'));
-    var locals = {};
+    let truncateGradientHeight = 15;
+    let template = _.template(require('./styleCompile.css.tmpl'));
+    let locals = {};
 
     // watch the value of the truncate:maxHeight config param
     $rootScope.$watch(function () {
diff --git a/src/ui/public/template_vis_type/TemplateRenderbot.js b/src/ui/public/template_vis_type/TemplateRenderbot.js
index 18def2803ad45..bbc04bc05a7ba 100644
--- a/src/ui/public/template_vis_type/TemplateRenderbot.js
+++ b/src/ui/public/template_vis_type/TemplateRenderbot.js
@@ -1,7 +1,7 @@
 define(function (require) {
   return function TemplateRenderbotFactory(Private, $compile, $rootScope) {
-    var _ = require('lodash');
-    var Renderbot = Private(require('ui/Vis/Renderbot'));
+    let _ = require('lodash');
+    let Renderbot = Private(require('ui/Vis/Renderbot'));
 
     _.class(TemplateRenderbot).inherits(Renderbot);
     function TemplateRenderbot(vis, $el, uiState) {
diff --git a/src/ui/public/template_vis_type/TemplateVisType.js b/src/ui/public/template_vis_type/TemplateVisType.js
index a025fc3f8814c..2d482c16e1359 100644
--- a/src/ui/public/template_vis_type/TemplateVisType.js
+++ b/src/ui/public/template_vis_type/TemplateVisType.js
@@ -1,8 +1,8 @@
 define(function (require) {
   return function TemplateVisTypeFactory(Private) {
-    var _ = require('lodash');
-    var VisType = Private(require('ui/Vis/VisType'));
-    var TemplateRenderbot = Private(require('ui/template_vis_type/TemplateRenderbot'));
+    let _ = require('lodash');
+    let VisType = Private(require('ui/Vis/VisType'));
+    let TemplateRenderbot = Private(require('ui/template_vis_type/TemplateRenderbot'));
 
     _.class(TemplateVisType).inherits(VisType);
     function TemplateVisType(opts) {
diff --git a/src/ui/public/testHarness/testHarness.js b/src/ui/public/testHarness/testHarness.js
index 1c62d655efce6..dbbd77b153cec 100644
--- a/src/ui/public/testHarness/testHarness.js
+++ b/src/ui/public/testHarness/testHarness.js
@@ -1,15 +1,15 @@
 /* global mocha */
 
 // chrome expects to be loaded first, let it get its way
-var chrome = require('ui/chrome');
+let chrome = require('ui/chrome');
 
-var Nonsense = require('Nonsense');
-var sinon = require('sinon');
-var $ = require('jquery');
-var _ = require('lodash');
-var parse = require('url').parse;
+let Nonsense = require('Nonsense');
+let sinon = require('sinon');
+let $ = require('jquery');
+let _ = require('lodash');
+let parse = require('url').parse;
 
-var StackTraceMapper = require('ui/StackTraceMapper');
+let StackTraceMapper = require('ui/StackTraceMapper');
 
 /*** the vislib tests have certain style requirements, so lets make sure they are met ***/
 $('body').attr('id', 'test-harness-body'); // so we can make high priority selectors
@@ -17,8 +17,8 @@ require('./testHarness.less');
 
 
 /*** Setup seeded random ***/
-var seedInput = parse(window.location.href, true).query.seed;
-var seed = _.add(seedInput, 0) || Date.now();
+let seedInput = parse(window.location.href, true).query.seed;
+let seed = _.add(seedInput, 0) || Date.now();
 Math.random = _.bindKey(new Nonsense(seed), 'frac');
 Math.random.nonsense = new Nonsense(seed);
 console.log('Random-ness seed: ' + seed);
@@ -38,7 +38,7 @@ before(function () {
   this.timeout(30000);
 
   let mapper;
-  var Runner = window.Mocha.Runner;
+  let Runner = window.Mocha.Runner;
 
   Runner.prototype.emit = _.wrap(Runner.prototype.emit, function (emit, event, test, err) {
     if (err && mapper) err = mapper.mapError(err);
diff --git a/src/ui/public/time_buckets/calc_auto_interval.js b/src/ui/public/time_buckets/calc_auto_interval.js
index 24a38f1731f6d..1aa7391077b5d 100644
--- a/src/ui/public/time_buckets/calc_auto_interval.js
+++ b/src/ui/public/time_buckets/calc_auto_interval.js
@@ -1,10 +1,10 @@
 define(function (require) {
   return function DateIntervalRoundingRulesProvider() {
-    var moment = require('moment');
+    let moment = require('moment');
     // these are the rounding rules used by roundInterval()
-    var d = require('moment').duration;
+    let d = require('moment').duration;
 
-    var roundingRules = [
+    let roundingRules = [
       [ d(500, 'ms'), d(100, 'ms') ],
       [ d(5, 'second'), d(1, 'second') ],
       [ d(7.5, 'second'), d(5, 'second') ],
@@ -23,16 +23,16 @@ define(function (require) {
       [ Infinity, d(1, 'year') ]
     ];
 
-    var revRoundingRules = roundingRules.slice(0).reverse();
+    let revRoundingRules = roundingRules.slice(0).reverse();
 
     function find(rules, check, last) {
       function pick(buckets, duration) {
-        var target = duration / buckets;
+        let target = duration / buckets;
         let lastResp;
 
-        for (var i = 0; i < rules.length; i++) {
-          var rule = rules[i];
-          var resp = check(rule[0], rule[1], target);
+        for (let i = 0; i < rules.length; i++) {
+          let rule = rules[i];
+          let resp = check(rule[0], rule[1], target);
 
           if (resp == null) {
             if (!last) continue;
@@ -45,12 +45,12 @@ define(function (require) {
         }
 
         // fallback to just a number of milliseconds, ensure ms is >= 1
-        var ms = Math.max(Math.floor(target), 1);
+        let ms = Math.max(Math.floor(target), 1);
         return moment.duration(ms, 'ms');
       }
 
       return function (buckets, duration) {
-        var interval = pick(buckets, duration);
+        let interval = pick(buckets, duration);
         if (interval) return moment.duration(interval._data);
       };
     }
diff --git a/src/ui/public/time_buckets/calc_es_interval.js b/src/ui/public/time_buckets/calc_es_interval.js
index 5f19f05d4da5b..8db9c4cd8fb5e 100644
--- a/src/ui/public/time_buckets/calc_es_interval.js
+++ b/src/ui/public/time_buckets/calc_es_interval.js
@@ -1,10 +1,10 @@
 define(function (require) {
   return function () {
-    var moment = require('moment');
-    var dateMath = require('ui/utils/dateMath');
+    let moment = require('moment');
+    let dateMath = require('ui/utils/dateMath');
 
-    var unitsDesc = dateMath.unitsDesc;
-    var largeMax = unitsDesc.indexOf('M');
+    let unitsDesc = dateMath.unitsDesc;
+    let largeMax = unitsDesc.indexOf('M');
 
     /**
      * Convert a moment.duration into an es
@@ -15,9 +15,9 @@ define(function (require) {
      * @return {object}
      */
     function esDuration(duration) {
-      for (var i = 0; i < unitsDesc.length; i++) {
-        var unit = unitsDesc[i];
-        var val = duration.as(unit);
+      for (let i = 0; i < unitsDesc.length; i++) {
+        let unit = unitsDesc[i];
+        let val = duration.as(unit);
         // find a unit that rounds neatly
         if (val >= 1 && Math.floor(val) === val) {
 
@@ -36,7 +36,7 @@ define(function (require) {
         }
       }
 
-      var ms = duration.as('ms');
+      let ms = duration.as('ms');
       return {
         value: ms,
         unit: 'ms',
diff --git a/src/ui/public/time_buckets/time_buckets.js b/src/ui/public/time_buckets/time_buckets.js
index 10bb9b5ff9733..50c6e1480eee6 100644
--- a/src/ui/public/time_buckets/time_buckets.js
+++ b/src/ui/public/time_buckets/time_buckets.js
@@ -1,13 +1,13 @@
 define(function (require) {
   return function IntervalHelperProvider(Private, timefilter, config) {
-    var _ = require('lodash');
-    var moment = require('moment');
+    let _ = require('lodash');
+    let moment = require('moment');
 
-    var dateMath = require('ui/utils/dateMath');
-    var parseInterval = require('ui/utils/parse_interval');
-    var calcAuto = Private(require('ui/time_buckets/calc_auto_interval'));
-    var calcEsInterval = Private(require('ui/time_buckets/calc_es_interval'));
-    var tzOffset = moment().format('Z');
+    let dateMath = require('ui/utils/dateMath');
+    let parseInterval = require('ui/utils/parse_interval');
+    let calcAuto = Private(require('ui/time_buckets/calc_auto_interval'));
+    let calcEsInterval = Private(require('ui/time_buckets/calc_es_interval'));
+    let tzOffset = moment().format('Z');
 
     function isValidMoment(m) {
       return m && ('isValid' in m) && m.isValid();
@@ -50,11 +50,11 @@ define(function (require) {
         bounds = _.isArray(input) ? input : [];
       }
 
-      var moments = _(bounds)
+      let moments = _(bounds)
       .map(_.ary(moment, 1))
       .sortBy(Number);
 
-      var valid = moments.size() === 2 && moments.every(isValidMoment);
+      let valid = moments.size() === 2 && moments.every(isValidMoment);
       if (!valid) {
         this.clearBounds();
         throw new Error('invalid bounds set: ' + input);
@@ -132,7 +132,7 @@ define(function (require) {
      * @param {object|string|moment.duration} input - see desc
      */
     TimeBuckets.prototype.setInterval = function (input) {
-      var interval = input;
+      let interval = input;
 
       // selection object -> val
       if (_.isObject(input)) {
@@ -196,13 +196,13 @@ define(function (require) {
      * @return {[type]} [description]
      */
     TimeBuckets.prototype.getInterval = function () {
-      var self = this;
-      var duration = self.getDuration();
+      let self = this;
+      let duration = self.getDuration();
       return decorateInterval(maybeScaleInterval(readInterval()));
 
       // either pull the interval from state or calculate the auto-interval
       function readInterval() {
-        var interval = self._i;
+        let interval = self._i;
         if (moment.isDuration(interval)) return interval;
         return calcAuto.near(config.get('histogram:barTarget'), duration);
       }
@@ -211,8 +211,8 @@ define(function (require) {
       function maybeScaleInterval(interval) {
         if (!self.hasBounds()) return interval;
 
-        var maxLength = config.get('histogram:maxBars');
-        var approxLen = duration / interval;
+        let maxLength = config.get('histogram:maxBars');
+        let approxLen = duration / interval;
         let scaled;
 
         if (approxLen > maxLength) {
@@ -233,13 +233,13 @@ define(function (require) {
 
       // append some TimeBuckets specific props to the interval
       function decorateInterval(interval) {
-        var esInterval = calcEsInterval(interval);
+        let esInterval = calcEsInterval(interval);
         interval.esValue = esInterval.value;
         interval.esUnit = esInterval.unit;
         interval.expression = esInterval.expression;
         interval.overflow = duration > interval ? moment.duration(interval - duration) : false;
 
-        var prettyUnits = moment.normalizeUnits(esInterval.unit);
+        let prettyUnits = moment.normalizeUnits(esInterval.unit);
         if (esInterval.value === 1) {
           interval.description = prettyUnits;
         } else {
@@ -262,11 +262,11 @@ define(function (require) {
      * @return {string}
      */
     TimeBuckets.prototype.getScaledDateFormat = function () {
-      var interval = this.getInterval();
-      var rules = config.get('dateFormat:scaled');
+      let interval = this.getInterval();
+      let rules = config.get('dateFormat:scaled');
 
-      for (var i = rules.length - 1; i >= 0; i--) {
-        var rule = rules[i];
+      for (let i = rules.length - 1; i >= 0; i--) {
+        let rule = rules[i];
         if (!rule[0] || interval >= moment.duration(rule[0])) {
           return rule[1];
         }
@@ -277,23 +277,23 @@ define(function (require) {
 
 
     TimeBuckets.__cached__ = function (self) {
-      var cache = {};
-      var sameMoment = same(moment.isMoment);
-      var sameDuration = same(moment.isDuration);
+      let cache = {};
+      let sameMoment = same(moment.isMoment);
+      let sameDuration = same(moment.isDuration);
 
-      var desc = {
+      let desc = {
         __cached__: {
           value: self
         },
       };
 
-      var breakers = {
+      let breakers = {
         setBounds: 'bounds',
         clearBounds: 'bounds',
         setInterval: 'interval'
       };
 
-      var resources = {
+      let resources = {
         bounds: {
           setup: function () {
             return [self._lb, self._ub];
@@ -325,16 +325,16 @@ define(function (require) {
       }
 
       function cacheBreaker(prop) {
-        var resource = resources[breakers[prop]];
-        var setup = resource.setup;
-        var changes = resource.changes;
-        var deps = resource.deps;
-        var fn = self[prop];
+        let resource = resources[breakers[prop]];
+        let setup = resource.setup;
+        let changes = resource.changes;
+        let deps = resource.deps;
+        let fn = self[prop];
 
         return {
           value: function cacheBreaker(input) {
-            var prev = setup.call(self);
-            var ret = fn.apply(self, arguments);
+            let prev = setup.call(self);
+            let ret = fn.apply(self, arguments);
 
             if (changes.call(self, prev)) {
               cache = {};
diff --git a/src/ui/public/timefilter/lib/diff_interval.js b/src/ui/public/timefilter/lib/diff_interval.js
index f345066d7a4a3..e52157fcb776f 100644
--- a/src/ui/public/timefilter/lib/diff_interval.js
+++ b/src/ui/public/timefilter/lib/diff_interval.js
@@ -1,10 +1,10 @@
 define(function (require) {
-  var _ = require('lodash');
+  let _ = require('lodash');
   return function diffTimeProvider(Private) {
-    var diff = Private(require('ui/utils/diff_time_picker_vals'));
+    let diff = Private(require('ui/utils/diff_time_picker_vals'));
 
     return function (self) {
-      var oldRefreshInterval = _.clone(self.refreshInterval);
+      let oldRefreshInterval = _.clone(self.refreshInterval);
 
       return function () {
         if (diff(self.refreshInterval, oldRefreshInterval)) {
diff --git a/src/ui/public/timefilter/lib/diff_time.js b/src/ui/public/timefilter/lib/diff_time.js
index 4dd2cbb2d211e..97c208a7e06d0 100644
--- a/src/ui/public/timefilter/lib/diff_time.js
+++ b/src/ui/public/timefilter/lib/diff_time.js
@@ -1,10 +1,10 @@
 define(function (require) {
-  var _ = require('lodash');
+  let _ = require('lodash');
   return function diffTimeProvider(Private) {
-    var diff = Private(require('ui/utils/diff_time_picker_vals'));
+    let diff = Private(require('ui/utils/diff_time_picker_vals'));
 
     return function (self) {
-      var oldTime = _.clone(self.time);
+      let oldTime = _.clone(self.time);
       return function () {
         if (diff(self.time, oldTime)) {
           self.emit('update');
diff --git a/src/ui/public/timefilter/timefilter.js b/src/ui/public/timefilter/timefilter.js
index 96b7b447ae025..795660dadcc69 100644
--- a/src/ui/public/timefilter/timefilter.js
+++ b/src/ui/public/timefilter/timefilter.js
@@ -8,17 +8,17 @@ define(function (require) {
   .get('kibana')
   .service('timefilter', function (Private, globalState, $rootScope, config) {
 
-    var _ = require('lodash');
-    var angular = require('angular');
-    var moment = require('moment');
-    var dateMath = require('ui/utils/dateMath');
-    var Events = Private(require('ui/events'));
-    var diff = Private(require('ui/utils/diff_time_picker_vals'));
+    let _ = require('lodash');
+    let angular = require('angular');
+    let moment = require('moment');
+    let dateMath = require('ui/utils/dateMath');
+    let Events = Private(require('ui/events'));
+    let diff = Private(require('ui/utils/diff_time_picker_vals'));
 
     require('ui/state_management/global_state');
 
     function convertISO8601(stringTime) {
-      var obj = moment(stringTime, 'YYYY-MM-DDTHH:mm:ss.SSSZ', true);
+      let obj = moment(stringTime, 'YYYY-MM-DDTHH:mm:ss.SSSZ', true);
       return obj.isValid() ? obj : stringTime;
     }
 
@@ -26,9 +26,9 @@ define(function (require) {
     function Timefilter() {
       Timefilter.Super.call(this);
 
-      var self = this;
-      var diffTime = Private(require('ui/timefilter/lib/diff_time'))(self);
-      var diffInterval = Private(require('ui/timefilter/lib/diff_interval'))(self);
+      let self = this;
+      let diffTime = Private(require('ui/timefilter/lib/diff_time'))(self);
+      let diffInterval = Private(require('ui/timefilter/lib/diff_interval'))(self);
 
       self.enabled = false;
 
@@ -38,8 +38,8 @@ define(function (require) {
       });
 
       self.consumeDefaults = _.once(function () {
-        var timeDefaults = config.get('timepicker:timeDefaults');
-        var refreshIntervalDefaults = config.get('timepicker:refreshIntervalDefaults');
+        let timeDefaults = config.get('timepicker:timeDefaults');
+        let refreshIntervalDefaults = config.get('timepicker:refreshIntervalDefaults');
 
         // These can be date math strings or moments.
         self.time = _.defaults(globalState.time || {}, timeDefaults);
@@ -47,8 +47,8 @@ define(function (require) {
 
         globalState.on('fetch_with_changes', function () {
           // clone and default to {} in one
-          var newTime = _.defaults({}, globalState.time, timeDefaults);
-          var newRefreshInterval = _.defaults({}, globalState.refreshInterval, refreshIntervalDefaults);
+          let newTime = _.defaults({}, globalState.time, timeDefaults);
+          let newRefreshInterval = _.defaults({}, globalState.refreshInterval, refreshIntervalDefaults);
 
           if (newTime) {
             if (newTime.to) newTime.to = convertISO8601(newTime.to);
@@ -78,10 +78,10 @@ define(function (require) {
 
     Timefilter.prototype.get = function (indexPattern) {
       let filter;
-      var timefield = indexPattern.timeFieldName && _.find(indexPattern.fields, {name: indexPattern.timeFieldName});
+      let timefield = indexPattern.timeFieldName && _.find(indexPattern.fields, {name: indexPattern.timeFieldName});
 
       if (timefield) {
-        var bounds = this.getBounds();
+        let bounds = this.getBounds();
         filter = {range : {}};
         filter.range[timefield.name] = {
           gte: bounds.min.valueOf(),
diff --git a/src/ui/public/timepicker/quick_ranges.js b/src/ui/public/timepicker/quick_ranges.js
index d9c57ebeb5fb6..c8ae493ef906a 100644
--- a/src/ui/public/timepicker/quick_ranges.js
+++ b/src/ui/public/timepicker/quick_ranges.js
@@ -1,5 +1,5 @@
 define(function (require) {
-  var module = require('ui/modules').get('kibana');
+  let module = require('ui/modules').get('kibana');
 
   module.constant('quickRanges', [
     { from: 'now/d',    to: 'now/d',    display: 'Today',                 section: 0 },
diff --git a/src/ui/public/timepicker/refresh_intervals.js b/src/ui/public/timepicker/refresh_intervals.js
index baf4ec0d4fbd6..5f951e7ab27b2 100644
--- a/src/ui/public/timepicker/refresh_intervals.js
+++ b/src/ui/public/timepicker/refresh_intervals.js
@@ -1,5 +1,5 @@
 define(function (require) {
-  var module = require('ui/modules').get('kibana');
+  let module = require('ui/modules').get('kibana');
 
   module.constant('refreshIntervals', [
     { value : 0, display: 'Off', section: 0},
diff --git a/src/ui/public/timepicker/time_units.js b/src/ui/public/timepicker/time_units.js
index c1de68e5d2d73..9e1cac99924b0 100644
--- a/src/ui/public/timepicker/time_units.js
+++ b/src/ui/public/timepicker/time_units.js
@@ -1,5 +1,5 @@
 define(function (require) {
-  var module = require('ui/modules').get('kibana');
+  let module = require('ui/modules').get('kibana');
 
   module.constant('timeUnits', {
     s: 'second',
diff --git a/src/ui/public/timepicker/timepicker.js b/src/ui/public/timepicker/timepicker.js
index 3aa1dd845c84f..611ef2dfc2b25 100644
--- a/src/ui/public/timepicker/timepicker.js
+++ b/src/ui/public/timepicker/timepicker.js
@@ -1,9 +1,9 @@
 define(function (require) {
-  var html = require('ui/timepicker/timepicker.html');
-  var module = require('ui/modules').get('ui/timepicker');
-  var _ = require('lodash');
-  var dateMath = require('ui/utils/dateMath');
-  var moment = require('moment');
+  let html = require('ui/timepicker/timepicker.html');
+  let module = require('ui/modules').get('ui/timepicker');
+  let _ = require('lodash');
+  let dateMath = require('ui/utils/dateMath');
+  let moment = require('moment');
 
   require('ui/directives/input_datetime');
   require('ui/directives/inequality');
@@ -24,7 +24,7 @@ define(function (require) {
       },
       template: html,
       controller: function ($scope) {
-        var init = function () {
+        let init = function () {
           $scope.setMode($scope.mode);
         };
 
@@ -74,8 +74,8 @@ define(function (require) {
             case 'quick':
               break;
             case 'relative':
-              var fromParts = $scope.from.toString().split('-');
-              var relativeParts = [];
+              let fromParts = $scope.from.toString().split('-');
+              let relativeParts = [];
 
               // Try to parse the relative time, if we can't use moment duration to guestimate
               if ($scope.to.toString() === 'now' && fromParts[0] === 'now' && fromParts[1]) {
@@ -85,11 +85,11 @@ define(function (require) {
                 $scope.relative.count = parseInt(relativeParts[1], 10);
                 $scope.relative.unit = relativeParts[2];
               } else {
-                var duration = moment.duration(moment().diff(dateMath.parse($scope.from)));
-                var units = _.pluck(_.clone($scope.relativeOptions).reverse(), 'value');
+                let duration = moment.duration(moment().diff(dateMath.parse($scope.from)));
+                let units = _.pluck(_.clone($scope.relativeOptions).reverse(), 'value');
                 if ($scope.from.toString().split('/')[1]) $scope.relative.round = true;
-                for (var i = 0; i < units.length; i++) {
-                  var as = duration.as(units[i]);
+                for (let i = 0; i < units.length; i++) {
+                  let as = duration.as(units[i]);
                   if (as > 1) {
                     $scope.relative.count = Math.round(as);
                     $scope.relative.unit = units[i];
@@ -121,7 +121,7 @@ define(function (require) {
         };
 
         $scope.formatRelative = function () {
-          var parsed = dateMath.parse(getRelativeString());
+          let parsed = dateMath.parse(getRelativeString());
           $scope.relative.preview =  parsed ? parsed.format($scope.format) : undefined;
           return parsed;
         };
diff --git a/src/ui/public/tooltip/tooltip.js b/src/ui/public/tooltip/tooltip.js
index 058239f396fec..9ac91a5c361e1 100644
--- a/src/ui/public/tooltip/tooltip.js
+++ b/src/ui/public/tooltip/tooltip.js
@@ -1,5 +1,5 @@
 define(function (require) {
-  var html = require('ui/tooltip/tooltip.html');
+  let html = require('ui/tooltip/tooltip.html');
 
   require('ui-bootstrap')
   .config(function ($tooltipProvider) {
diff --git a/src/ui/public/typeahead/_input.js b/src/ui/public/typeahead/_input.js
index 809893c6481a2..004676b215dc4 100644
--- a/src/ui/public/typeahead/_input.js
+++ b/src/ui/public/typeahead/_input.js
@@ -1,6 +1,6 @@
 define(function (require) {
-  var _ = require('lodash');
-  var typeahead = require('ui/modules').get('kibana/typeahead');
+  let _ = require('lodash');
+  let typeahead = require('ui/modules').get('kibana/typeahead');
 
   require('ui/notify/directives');
 
@@ -11,8 +11,8 @@ define(function (require) {
       require: ['^ngModel', '^kbnTypeahead'],
 
       link: function ($scope, $el, $attr, deps) {
-        var model = deps[0];
-        var typeaheadCtrl = deps[1];
+        let model = deps[0];
+        let typeaheadCtrl = deps[1];
 
         typeaheadCtrl.setInputModel(model);
 
diff --git a/src/ui/public/typeahead/_items.js b/src/ui/public/typeahead/_items.js
index 1445fe344fdd0..be7ea1960be78 100644
--- a/src/ui/public/typeahead/_items.js
+++ b/src/ui/public/typeahead/_items.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  var _ = require('lodash');
-  var typeahead = require('ui/modules').get('kibana/typeahead');
-  var listTemplate = require('ui/typeahead/partials/typeahead-items.html');
+  let _ = require('lodash');
+  let typeahead = require('ui/modules').get('kibana/typeahead');
+  let listTemplate = require('ui/typeahead/partials/typeahead-items.html');
 
   require('ui/notify/directives');
 
diff --git a/src/ui/public/typeahead/typeahead.js b/src/ui/public/typeahead/typeahead.js
index 48c65279ab8ec..4a7eca749f228 100644
--- a/src/ui/public/typeahead/typeahead.js
+++ b/src/ui/public/typeahead/typeahead.js
@@ -1,13 +1,13 @@
 define(function (require) {
-  var _ = require('lodash');
-  var typeahead = require('ui/modules').get('kibana/typeahead');
+  let _ = require('lodash');
+  let typeahead = require('ui/modules').get('kibana/typeahead');
 
   require('ui/typeahead/typeahead.less');
   require('ui/typeahead/_input');
   require('ui/typeahead/_items');
 
   typeahead.directive('kbnTypeahead', function () {
-    var keyMap = {
+    let keyMap = {
       ESC: 27,
       UP: 38,
       DOWN: 40,
@@ -23,7 +23,7 @@ define(function (require) {
       controllerAs: 'typeahead',
 
       controller: function ($scope, $element, $timeout, PersistedLog, config) {
-        var self = this;
+        let self = this;
         self.form = $element.closest('form');
         self.query = '';
         self.hidden = true;
@@ -76,7 +76,7 @@ define(function (require) {
         };
 
         self.activateNext = function () {
-          var index = self.getActiveIndex();
+          let index = self.getActiveIndex();
           if (index == null) {
             index = 0;
           } else if (index < $scope.filteredItems.length - 1) {
@@ -87,7 +87,7 @@ define(function (require) {
         };
 
         self.activatePrev = function () {
-          var index = self.getActiveIndex();
+          let index = self.getActiveIndex();
 
           if (index > 0 && index != null) {
             --index;
@@ -138,7 +138,7 @@ define(function (require) {
         };
 
         self.keypressHandler = function (ev) {
-          var keyCode = ev.which || ev.keyCode;
+          let keyCode = ev.which || ev.keyCode;
 
           if (self.focused) {
             self.hidden = false;
@@ -194,11 +194,11 @@ define(function (require) {
           }
 
           // update the filteredItems using the query
-          var beginningMatches = $scope.items.filter(function (item) {
+          let beginningMatches = $scope.items.filter(function (item) {
             return item.indexOf(query) === 0;
           });
 
-          var otherMatches = $scope.items.filter(function (item) {
+          let otherMatches = $scope.items.filter(function (item) {
             return item.indexOf(query) > 0;
           });