diff --git a/src/ui/public/url/url.js b/src/ui/public/url/url.js
index a5c7cf0eebf30..cd3ed891e28fb 100644
--- a/src/ui/public/url/url.js
+++ b/src/ui/public/url/url.js
@@ -8,7 +8,7 @@ uiModules.get('kibana/url')
 .service('kbnUrl', function (Private) { return Private(KbnUrlProvider); });
 
 function KbnUrlProvider($route, $location, $rootScope, globalState, $parse, getAppState) {
-  var self = this;
+  let self = this;
 
   /**
    * Navigate to a url
@@ -70,10 +70,10 @@ function KbnUrlProvider($route, $location, $rootScope, globalState, $parse, getA
 
     return template.replace(/\{\{([^\}]+)\}\}/g, function (match, expr) {
       // remove filters
-      var key = expr.split('|')[0].trim();
+      let key = expr.split('|')[0].trim();
 
       // verify that the expression can be evaluated
-      var p = $parse(key)(paramObj);
+      let p = $parse(key)(paramObj);
 
       // if evaluation can't be made, throw
       if (_.isUndefined(p)) {
@@ -109,7 +109,7 @@ function KbnUrlProvider($route, $location, $rootScope, globalState, $parse, getA
    * @return {string} - the computed url
    */
   self.getRouteUrl = function (obj, route) {
-    var template = obj && obj.routes && obj.routes[route];
+    let template = obj && obj.routes && obj.routes[route];
     if (template) return self.eval(template, obj);
   };
 
@@ -143,7 +143,7 @@ function KbnUrlProvider($route, $location, $rootScope, globalState, $parse, getA
   let reloading;
 
   self._changeLocation = function (type, url, paramObj, replace) {
-    var prev = {
+    let prev = {
       path: $location.path(),
       search: $location.search()
     };
@@ -152,13 +152,13 @@ function KbnUrlProvider($route, $location, $rootScope, globalState, $parse, getA
     $location[type](url);
     if (replace) $location.replace();
 
-    var next = {
+    let next = {
       path: $location.path(),
       search: $location.search()
     };
 
     if (self._shouldAutoReload(next, prev)) {
-      var appState = getAppState();
+      let appState = getAppState();
       if (appState) appState.destroy();
 
       reloading = $rootScope.$on('$locationChangeSuccess', function () {
@@ -174,13 +174,13 @@ function KbnUrlProvider($route, $location, $rootScope, globalState, $parse, getA
   self._shouldAutoReload = function (next, prev) {
     if (reloading) return false;
 
-    var route = $route.current && $route.current.$$route;
+    let route = $route.current && $route.current.$$route;
     if (!route) return false;
 
     if (next.path !== prev.path) return false;
 
-    var reloadOnSearch = route.reloadOnSearch;
-    var searchSame = _.isEqual(next.search, prev.search);
+    let reloadOnSearch = route.reloadOnSearch;
+    let searchSame = _.isEqual(next.search, prev.search);
 
     return (reloadOnSearch && searchSame) || !reloadOnSearch;
   };
diff --git a/src/ui/public/vis/agg_config.js b/src/ui/public/vis/agg_config.js
index 8e5f76772931d..ab6c649bce58b 100644
--- a/src/ui/public/vis/agg_config.js
+++ b/src/ui/public/vis/agg_config.js
@@ -1,10 +1,10 @@
 import _ from 'lodash';
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 export default function AggConfigFactory(Private, fieldTypeFilter) {
-  var fieldFormats = Private(RegistryFieldFormatsProvider);
+  let fieldFormats = Private(RegistryFieldFormatsProvider);
 
   function AggConfig(vis, opts) {
-    var self = this;
+    let self = this;
 
     self.id = String(opts.id || AggConfig.nextId(vis.aggs));
     self.vis = vis;
@@ -26,13 +26,13 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
    * @return {array} - the list that was passed in
    */
   AggConfig.ensureIds = function (list) {
-    var have = [];
-    var haveNot = [];
+    let have = [];
+    let haveNot = [];
     list.forEach(function (obj) {
       (obj.id ? have : haveNot).push(obj);
     });
 
-    var nextId = AggConfig.nextId(have);
+    let nextId = AggConfig.nextId(have);
     haveNot.forEach(function (obj) {
       obj.id = String(nextId++);
     });
@@ -97,12 +97,12 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
    * @return {undefined}
    */
   AggConfig.prototype.fillDefaults = function (from) {
-    var self = this;
+    let self = this;
     from = from || self.params || {};
-    var to = self.params = {};
+    let to = self.params = {};
 
     self.getAggParams().forEach(function (aggParam) {
-      var val = from[aggParam.name];
+      let val = from[aggParam.name];
 
       if (val == null) {
         if (aggParam.default == null) return;
@@ -116,11 +116,11 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
       }
 
       if (aggParam.deserialize) {
-        var isTyped = _.isFunction(aggParam.type);
+        let isTyped = _.isFunction(aggParam.type);
 
-        var isType = isTyped && (val instanceof aggParam.type);
-        var isObject = !isTyped && _.isObject(val);
-        var isDeserialized = (isType || isObject);
+        let isType = isTyped && (val instanceof aggParam.type);
+        let isObject = !isTyped && _.isObject(val);
+        let isDeserialized = (isType || isObject);
 
         if (!isDeserialized) {
           val = aggParam.deserialize(val, self);
@@ -140,12 +140,12 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
    * @return {object} the new params object
    */
   AggConfig.prototype.resetParams = function () {
-    var fieldParam = this.type && this.type.params.byName.field;
+    let fieldParam = this.type && this.type.params.byName.field;
     let field;
 
     if (fieldParam) {
-      var prevField = this.params.field;
-      var fieldOpts = fieldTypeFilter(this.vis.indexPattern.fields, fieldParam.filterFieldTypes);
+      let prevField = this.params.field;
+      let fieldOpts = fieldTypeFilter(this.vis.indexPattern.fields, fieldParam.filterFieldTypes);
       field = _.contains(fieldOpts, prevField) ? prevField : null;
     }
 
@@ -161,10 +161,10 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
       throw new TypeError('The "' + this.type.title + '" aggregation does not support filtering.');
     }
 
-    var field = this.field();
-    var label = this.fieldDisplayName();
+    let field = this.field();
+    let label = this.fieldDisplayName();
     if (field && !field.filterable) {
-      var message = 'The "' + label + '" field can not be used for filtering.';
+      let message = 'The "' + label + '" field can not be used for filtering.';
       if (field.scripted) {
         message = 'The "' + label + '" field is scripted and can not be used for filtering.';
       }
@@ -181,7 +181,7 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
    * @return {[type]} [description]
    */
   AggConfig.prototype.requesting = function () {
-    var self = this;
+    let self = this;
     self.type && self.type.params.forEach(function (param) {
       if (param.onRequest) param.onRequest(self);
     });
@@ -198,14 +198,14 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
    */
   AggConfig.prototype.toDsl = function () {
     if (this.type.hasNoDsl) return;
-    var output = this.write();
+    let output = this.write();
 
-    var configDsl = {};
+    let configDsl = {};
     configDsl[this.type.dslName || this.type.name] = output.params;
 
     // if the config requires subAggs, write them to the dsl as well
     if (output.subAggs) {
-      var subDslLvl = configDsl.aggs || (configDsl.aggs = {});
+      let subDslLvl = configDsl.aggs || (configDsl.aggs = {});
       output.subAggs.forEach(function nestAdhocSubAggs(subAggConfig) {
         subDslLvl[subAggConfig.id] = subAggConfig.toDsl();
       });
@@ -215,11 +215,11 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
   };
 
   AggConfig.prototype.toJSON = function () {
-    var self = this;
-    var params = self.params;
+    let self = this;
+    let params = self.params;
 
-    var outParams = _.transform(self.getAggParams(), function (out, aggParam) {
-      var val = params[aggParam.name];
+    let outParams = _.transform(self.getAggParams(), function (out, aggParam) {
+      let val = params[aggParam.name];
 
       // don't serialize undefined/null values
       if (val == null) return;
@@ -264,7 +264,7 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
     }
 
     if (!this.type) return '';
-    var pre = (_.get(this.vis, 'params.mode') === 'percentage') ? 'Percentage of ' : '';
+    let pre = (_.get(this.vis, 'params.mode') === 'percentage') ? 'Percentage of ' : '';
     return pre += this.type.makeLabel(this);
   };
 
@@ -273,31 +273,31 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
   };
 
   AggConfig.prototype.fieldFormatter = function (contentType, defaultFormat) {
-    var format = this.type && this.type.getFormat(this);
+    let format = this.type && this.type.getFormat(this);
     if (format) return format.getConverterFor(contentType);
     return this.fieldOwnFormatter(contentType, defaultFormat);
   };
 
   AggConfig.prototype.fieldOwnFormatter = function (contentType, defaultFormat) {
-    var field = this.field();
-    var format = field && field.format;
+    let field = this.field();
+    let format = field && field.format;
     if (!format) format = defaultFormat;
     if (!format) format = fieldFormats.getDefaultInstance('string');
     return format.getConverterFor(contentType);
   };
 
   AggConfig.prototype.fieldName = function () {
-    var field = this.field();
+    let field = this.field();
     return field ? field.name : '';
   };
 
   AggConfig.prototype.fieldDisplayName = function () {
-    var field = this.field();
+    let field = this.field();
     return field ? (field.displayName || this.fieldName()) : '';
   };
 
   AggConfig.prototype.fieldIsTimeField = function () {
-    var timeFieldName = this.vis.indexPattern.timeFieldName;
+    let timeFieldName = this.vis.indexPattern.timeFieldName;
     return timeFieldName && this.fieldName() === timeFieldName;
   };
 
diff --git a/src/ui/public/vis/agg_config_result.js b/src/ui/public/vis/agg_config_result.js
index b7dac72820efa..4df97b55477c6 100644
--- a/src/ui/public/vis/agg_config_result.js
+++ b/src/ui/public/vis/agg_config_result.js
@@ -1,5 +1,5 @@
 define(function () {
-  var i = 0;
+  let i = 0;
 
   function AggConfigResult(aggConfig, parent, value, key) {
     this.key = key;
diff --git a/src/ui/public/vis/agg_configs.js b/src/ui/public/vis/agg_configs.js
index a112144ba803e..08f6798b7b2e5 100644
--- a/src/ui/public/vis/agg_configs.js
+++ b/src/ui/public/vis/agg_configs.js
@@ -3,13 +3,13 @@ import IndexedArray from 'ui/indexed_array';
 import VisAggConfigProvider from 'ui/vis/agg_config';
 import AggTypesIndexProvider from 'ui/agg_types/index';
 export default function AggConfigsFactory(Private) {
-  var AggConfig = Private(VisAggConfigProvider);
+  let AggConfig = Private(VisAggConfigProvider);
 
   AggConfig.aggTypes = Private(AggTypesIndexProvider);
 
   _.class(AggConfigs).inherits(IndexedArray);
   function AggConfigs(vis, configStates) {
-    var self = this;
+    let self = this;
     self.vis = vis;
 
     configStates = AggConfig.ensureIds(configStates || []);
@@ -36,9 +36,9 @@ export default function AggConfigsFactory(Private) {
       })
       .each(function (schema) {
         if (!self.bySchemaName[schema.name]) {
-          var defaults = schema.defaults.slice(0, schema.max);
+          let defaults = schema.defaults.slice(0, schema.max);
           _.each(defaults, function (defaultState) {
-            var state = _.defaults({ id: AggConfig.nextId(self) }, defaultState);
+            let state = _.defaults({ id: AggConfig.nextId(self) }, defaultState);
             self.push(new AggConfig(vis, state));
           });
         }
@@ -48,7 +48,7 @@ export default function AggConfigsFactory(Private) {
   }
 
   AggConfigs.prototype.toDsl = function () {
-    var dslTopLvl = {};
+    let dslTopLvl = {};
     let dslLvlCursor;
     let nestedMetrics;
 
@@ -76,8 +76,8 @@ export default function AggConfigsFactory(Private) {
         // start at the top level
         dslLvlCursor = dslTopLvl;
       } else {
-        var prevConfig = list[i - 1];
-        var prevDsl = dslLvlCursor[prevConfig.id];
+        let prevConfig = list[i - 1];
+        let prevDsl = dslLvlCursor[prevConfig.id];
 
         // advance the cursor and nest under the previous agg, or
         // put it on the same level if the previous agg doesn't accept
@@ -85,7 +85,7 @@ export default function AggConfigsFactory(Private) {
         dslLvlCursor = prevDsl.aggs || dslLvlCursor;
       }
 
-      var dsl = dslLvlCursor[config.id] = config.toDsl();
+      let dsl = dslLvlCursor[config.id] = config.toDsl();
       let subAggs;
 
       if (config.schema.group === 'buckets' && i < list.length - 1) {
@@ -122,7 +122,7 @@ export default function AggConfigsFactory(Private) {
    */
   AggConfigs.prototype.getResponseAggs = function () {
     return this.getRequestAggs().reduce(function (responseValuesAggs, agg) {
-      var aggs = agg.getResponseAggs();
+      let aggs = agg.getResponseAggs();
       return aggs ? responseValuesAggs.concat(aggs) : responseValuesAggs;
     }, []);
   };
@@ -137,7 +137,7 @@ export default function AggConfigsFactory(Private) {
    */
   AggConfigs.prototype.getResponseAggById = function (id) {
     id = String(id);
-    var reqAgg = _.find(this.getRequestAggs(), function (agg) {
+    let reqAgg = _.find(this.getRequestAggs(), function (agg) {
       return id.substr(0, String(agg.id).length) === agg.id;
     });
     if (!reqAgg) return;
diff --git a/src/ui/public/vis/schemas.js b/src/ui/public/vis/schemas.js
index 3eeea29d6be73..f35c1a6d1324d 100644
--- a/src/ui/public/vis/schemas.js
+++ b/src/ui/public/vis/schemas.js
@@ -2,10 +2,10 @@ import _ from 'lodash';
 import IndexedArray from 'ui/indexed_array';
 import AggTypesAggParamsProvider from 'ui/agg_types/agg_params';
 export default function VisTypeSchemasFactory(Private) {
-  var AggParams = Private(AggTypesAggParamsProvider);
+  let AggParams = Private(AggTypesAggParamsProvider);
 
   function Schemas(schemas) {
-    var self = this;
+    let self = this;
 
     _(schemas || [])
     .map(function (schema) {
diff --git a/src/ui/public/vis/vis.js b/src/ui/public/vis/vis.js
index fd7d5fda72823..dbf29fe416429 100644
--- a/src/ui/public/vis/vis.js
+++ b/src/ui/public/vis/vis.js
@@ -3,11 +3,11 @@ import AggTypesIndexProvider from 'ui/agg_types/index';
 import RegistryVisTypesProvider from 'ui/registry/vis_types';
 import VisAggConfigsProvider from 'ui/vis/agg_configs';
 export default function VisFactory(Notifier, Private) {
-  var aggTypes = Private(AggTypesIndexProvider);
-  var visTypes = Private(RegistryVisTypesProvider);
-  var AggConfigs = Private(VisAggConfigsProvider);
+  let aggTypes = Private(AggTypesIndexProvider);
+  let visTypes = Private(RegistryVisTypesProvider);
+  let AggConfigs = Private(VisAggConfigsProvider);
 
-  var notify = new Notifier({
+  let notify = new Notifier({
     location: 'Vis'
   });
 
@@ -31,10 +31,10 @@ export default function VisFactory(Notifier, Private) {
       type = visTypes.byName[type || 'histogram'];
     }
 
-    var schemas = type.schemas;
+    let schemas = type.schemas;
 
-    var aggs = _.transform(oldState, function (newConfigs, oldConfigs, oldGroupName) {
-      var schema = schemas.all.byName[oldGroupName];
+    let aggs = _.transform(oldState, function (newConfigs, oldConfigs, oldGroupName) {
+      let schema = schemas.all.byName[oldGroupName];
 
       if (!schema) {
         notify.log('unable to match old schema', oldGroupName, 'to a new schema');
@@ -42,12 +42,12 @@ export default function VisFactory(Notifier, Private) {
       }
 
       oldConfigs.forEach(function (oldConfig) {
-        var agg = {
+        let agg = {
           schema: schema.name,
           type: oldConfig.agg,
         };
 
-        var aggType = aggTypes.byName[agg.type];
+        let aggType = aggTypes.byName[agg.type];
         if (!aggType) {
           notify.log('unable to find an agg type for old confg', oldConfig);
           return;
@@ -118,7 +118,7 @@ export default function VisFactory(Notifier, Private) {
   };
 
   Vis.prototype.hasSchemaAgg = function (schemaName, aggTypeName) {
-    var aggs = this.aggs.bySchemaName[schemaName] || [];
+    let aggs = this.aggs.bySchemaName[schemaName] || [];
     return aggs.some(function (agg) {
       if (!agg.type || !agg.type.name) return false;
       return agg.type.name === aggTypeName;
diff --git a/src/ui/public/vis/vis_type.js b/src/ui/public/vis/vis_type.js
index 7df7eca820c6a..96ed7e1d2a00d 100644
--- a/src/ui/public/vis/vis_type.js
+++ b/src/ui/public/vis/vis_type.js
@@ -1,7 +1,7 @@
 import VisSchemasProvider from 'ui/vis/schemas';
 
 export default function VisTypeFactory(Private) {
-  var VisTypeSchemas = Private(VisSchemasProvider);
+  let VisTypeSchemas = Private(VisSchemasProvider);
 
   function VisType(opts) {
     opts = opts || {};
diff --git a/src/ui/public/vislib_vis_type/build_chart_data.js b/src/ui/public/vislib_vis_type/build_chart_data.js
index 8b584653ada63..84f2fc5875f42 100644
--- a/src/ui/public/vislib_vis_type/build_chart_data.js
+++ b/src/ui/public/vislib_vis_type/build_chart_data.js
@@ -2,23 +2,23 @@ import AggResponseIndexProvider from 'ui/agg_response/index';
 import AggResponseTabifyTableProvider from 'ui/agg_response/tabify/_table';
 
 export default function VislibVisBuildChartData(Private) {
-  var aggResponse = Private(AggResponseIndexProvider);
-  var Table = Private(AggResponseTabifyTableProvider);
+  let aggResponse = Private(AggResponseIndexProvider);
+  let Table = Private(AggResponseTabifyTableProvider);
 
   return function (esResponse) {
-    var vis = this.vis;
+    let vis = this.vis;
 
     if (vis.isHierarchical()) {
       // the hierarchical converter is very self-contained (woot!)
       return aggResponse.hierarchical(vis, esResponse);
     }
 
-    var tableGroup = aggResponse.tabify(vis, esResponse, {
+    let tableGroup = aggResponse.tabify(vis, esResponse, {
       canSplit: true,
       asAggConfigResults: true
     });
 
-    var converted = convertTableGroup(vis, tableGroup);
+    let converted = convertTableGroup(vis, tableGroup);
     if (!converted) {
       // mimic a row of tables that doesn't have any tables
       // https://github.com/elastic/kibana/blob/7bfb68cd24ed42b1b257682f93c50cd8d73e2520/src/kibana/components/vislib/components/zero_injection/inject_zeros.js#L32
@@ -31,11 +31,11 @@ export default function VislibVisBuildChartData(Private) {
   };
 
   function convertTableGroup(vis, tableGroup) {
-    var tables = tableGroup.tables;
-    var firstChild = tables[0];
+    let tables = tableGroup.tables;
+    let firstChild = tables[0];
     if (firstChild instanceof Table) {
 
-      var chart = convertTable(vis, firstChild);
+      let chart = convertTable(vis, firstChild);
       // if chart is within a split, assign group title to its label
       if (tableGroup.$parent) {
         chart.label = tableGroup.title;
@@ -44,13 +44,13 @@ export default function VislibVisBuildChartData(Private) {
     }
 
     if (!tables.length) return;
-    var out = {};
+    let out = {};
     let outList;
 
     tables.forEach(function (table) {
       if (!outList) {
-        var aggConfig = table.aggConfig;
-        var direction = aggConfig.params.row ? 'rows' : 'columns';
+        let aggConfig = table.aggConfig;
+        let direction = aggConfig.params.row ? 'rows' : 'columns';
         outList = out[direction] = [];
       }
 
diff --git a/src/ui/public/vislib_vis_type/vislib_renderbot.js b/src/ui/public/vislib_vis_type/vislib_renderbot.js
index 956a61a7047ef..1cbbf1a424c21 100644
--- a/src/ui/public/vislib_vis_type/vislib_renderbot.js
+++ b/src/ui/public/vislib_vis_type/vislib_renderbot.js
@@ -3,9 +3,9 @@ import VislibProvider from 'ui/vislib';
 import VisRenderbotProvider from 'ui/vis/renderbot';
 import VislibVisTypeBuildChartDataProvider from 'ui/vislib_vis_type/build_chart_data';
 module.exports = function VislibRenderbotFactory(Private) {
-  var vislib = Private(VislibProvider);
-  var Renderbot = Private(VisRenderbotProvider);
-  var buildChartData = Private(VislibVisTypeBuildChartDataProvider);
+  let vislib = Private(VislibProvider);
+  let Renderbot = Private(VisRenderbotProvider);
+  let buildChartData = Private(VislibVisTypeBuildChartDataProvider);
 
   _.class(VislibRenderbot).inherits(Renderbot);
   function VislibRenderbot(vis, $el, uiState) {
@@ -14,7 +14,7 @@ module.exports = function VislibRenderbotFactory(Private) {
   }
 
   VislibRenderbot.prototype._createVis = function () {
-    var self = this;
+    let self = this;
 
     if (self.vislibVis) self.destroy();
 
@@ -29,7 +29,7 @@ module.exports = function VislibRenderbotFactory(Private) {
   };
 
   VislibRenderbot.prototype._getVislibParams = function () {
-    var self = this;
+    let self = this;
 
     return _.assign(
       {},
@@ -50,9 +50,9 @@ module.exports = function VislibRenderbotFactory(Private) {
   };
 
   VislibRenderbot.prototype.destroy = function () {
-    var self = this;
+    let self = this;
 
-    var vislibVis = self.vislibVis;
+    let vislibVis = self.vislibVis;
 
     _.forOwn(self.vis.listeners, function (listener, event) {
       vislibVis.off(event, listener);
@@ -62,10 +62,10 @@ module.exports = function VislibRenderbotFactory(Private) {
   };
 
   VislibRenderbot.prototype.updateParams = function () {
-    var self = this;
+    let self = this;
 
     // get full vislib params object
-    var newParams = self._getVislibParams();
+    let newParams = self._getVislibParams();
 
     // if there's been a change, replace the vis
     if (!_.isEqual(newParams, self.vislibParams)) self._createVis();
diff --git a/src/ui/public/vislib_vis_type/vislib_vis_type.js b/src/ui/public/vislib_vis_type/vislib_vis_type.js
index c3c090f3bdfff..a18977bc2ca73 100644
--- a/src/ui/public/vislib_vis_type/vislib_vis_type.js
+++ b/src/ui/public/vislib_vis_type/vislib_vis_type.js
@@ -9,10 +9,10 @@ import AggResponsePointSeriesPointSeriesProvider from 'ui/agg_response/point_ser
 import VislibVisTypeVislibRenderbotProvider from 'ui/vislib_vis_type/vislib_renderbot';
 export default function VislibVisTypeFactory(Private) {
 
-  var VisTypeSchemas = Private(VisSchemasProvider);
-  var VisType = Private(VisVisTypeProvider);
-  var pointSeries = Private(AggResponsePointSeriesPointSeriesProvider);
-  var VislibRenderbot = Private(VislibVisTypeVislibRenderbotProvider);
+  let VisTypeSchemas = Private(VisSchemasProvider);
+  let VisType = Private(VisVisTypeProvider);
+  let pointSeries = Private(AggResponsePointSeriesPointSeriesProvider);
+  let VislibRenderbot = Private(VislibVisTypeVislibRenderbotProvider);
 
 
   _.class(VislibVisType).inherits(VisType);
diff --git a/src/ui/public/visualize/spy.js b/src/ui/public/visualize/spy.js
index 8b91ed0d0a77e..e8df7aa336b80 100644
--- a/src/ui/public/visualize/spy.js
+++ b/src/ui/public/visualize/spy.js
@@ -7,16 +7,16 @@ uiModules
   .get('app/visualize')
   .directive('visualizeSpy', function (Private, $compile) {
 
-    var spyModes = Private(RegistrySpyModesProvider);
-    var defaultMode = spyModes.inOrder[0].name;
+    let spyModes = Private(RegistrySpyModesProvider);
+    let defaultMode = spyModes.inOrder[0].name;
 
     return {
       restrict: 'E',
       template: spyTemplate,
       link: function ($scope, $el) {
         let currentSpy;
-        var $container = $el.find('.visualize-spy-container');
-        var fullPageSpy = _.get($scope.spy, 'mode.fill', false);
+        let $container = $el.find('.visualize-spy-container');
+        let fullPageSpy = _.get($scope.spy, 'mode.fill', false);
         $scope.modes = spyModes;
         $scope.spy.params = $scope.spy.params || {};
 
@@ -30,8 +30,8 @@ uiModules
           };
         }
 
-        var renderSpy = function (spyName) {
-          var newMode = $scope.modes.byName[spyName];
+        let renderSpy = function (spyName) {
+          let newMode = $scope.modes.byName[spyName];
 
           // clear the current value
           if (currentSpy) {
@@ -57,7 +57,7 @@ uiModules
         };
 
         $scope.toggleDisplay = function () {
-          var modeName = _.get($scope.spy, 'mode.name');
+          let modeName = _.get($scope.spy, 'mode.name');
           $scope.setSpyMode(modeName ? null : defaultMode);
         };
 
@@ -74,7 +74,7 @@ uiModules
 
         if ($scope.uiState) {
           // sync external uiState changes
-          var syncUIState = () => $scope.spy.mode = $scope.uiState.get('spy.mode');
+          let syncUIState = () => $scope.spy.mode = $scope.uiState.get('spy.mode');
           $scope.uiState.on('change', syncUIState);
           $scope.$on('$destroy', () => $scope.uiState.off('change', syncUIState));
         }
@@ -85,7 +85,7 @@ uiModules
           'spy.mode.fill'
         ], function (newVals, oldVals) {
           // update the ui state, but only if it really changes
-          var changedVals = newVals.filter((val) => !_.isUndefined(val)).length > 0;
+          let changedVals = newVals.filter((val) => !_.isUndefined(val)).length > 0;
           if (changedVals && !_.isEqual(newVals, oldVals)) {
             if ($scope.uiState) $scope.uiState.set('spy.mode', $scope.spy.mode);
           }
diff --git a/src/ui/public/visualize/visualize.js b/src/ui/public/visualize/visualize.js
index 8b02f5d6fb5bd..86c9a5beae6be 100644
--- a/src/ui/public/visualize/visualize.js
+++ b/src/ui/public/visualize/visualize.js
@@ -11,9 +11,9 @@ uiModules
 .directive('visualize', function (Notifier, SavedVis, indexPatterns, Private, config, $timeout) {
 
 
-  var visTypes = Private(RegistryVisTypesProvider);
+  let visTypes = Private(RegistryVisTypesProvider);
 
-  var notify = new Notifier({
+  let notify = new Notifier({
     location: 'Visualize'
   });
 
@@ -30,7 +30,7 @@ uiModules
     template: visualizeTemplate,
     link: function ($scope, $el, attr) {
       let chart; // set in "vis" watcher
-      var minVisChartHeight = 180;
+      let minVisChartHeight = 180;
 
       if (_.isUndefined($scope.showSpyPanel)) {
         $scope.showSpyPanel = true;
@@ -38,19 +38,19 @@ uiModules
 
       function getter(selector) {
         return function () {
-          var $sel = $el.find(selector);
+          let $sel = $el.find(selector);
           if ($sel.size()) return $sel;
         };
       }
 
-      var getVisEl = getter('.visualize-chart');
-      var getVisContainer = getter('.vis-container');
+      let getVisEl = getter('.visualize-chart');
+      let getVisContainer = getter('.vis-container');
 
       // Show no results message when isZeroHits is true and it requires search
       $scope.showNoResultsMessage = function () {
-        var requiresSearch = _.get($scope, 'vis.type.requiresSearch');
-        var isZeroHits = _.get($scope,'esResp.hits.total') === 0;
-        var shouldShowMessage = !_.get($scope, 'vis.params.handleNoResults');
+        let requiresSearch = _.get($scope, 'vis.type.requiresSearch');
+        let isZeroHits = _.get($scope,'esResp.hits.total') === 0;
+        let shouldShowMessage = !_.get($scope, 'vis.params.handleNoResults');
 
         return Boolean(requiresSearch && isZeroHits && shouldShowMessage);
       };
@@ -58,9 +58,9 @@ uiModules
       $scope.spy = {};
       $scope.spy.mode = ($scope.uiState) ? $scope.uiState.get('spy.mode', {}) : {};
 
-      var applyClassNames = function () {
-        var $visEl = getVisContainer();
-        var fullSpy = ($scope.spy.mode && ($scope.spy.mode.fill || $scope.fullScreenSpy));
+      let applyClassNames = function () {
+        let $visEl = getVisContainer();
+        let fullSpy = ($scope.spy.mode && ($scope.spy.mode.fill || $scope.fullScreenSpy));
 
         $visEl.toggleClass('spy-only', Boolean(fullSpy));
 
@@ -73,8 +73,8 @@ uiModules
 
       // we need to wait for some watchers to fire at least once
       // before we are "ready", this manages that
-      var prereq = (function () {
-        var fns = [];
+      let prereq = (function () {
+        let fns = [];
 
         return function register(fn) {
           fns.push(fn);
@@ -92,14 +92,14 @@ uiModules
         };
       }());
 
-      var loadingDelay = config.get('visualization:loadingDelay');
+      let loadingDelay = config.get('visualization:loadingDelay');
       $scope.loadingStyle = {
         '-webkit-transition-delay': loadingDelay,
         'transition-delay': loadingDelay
       };
 
       function shouldHaveFullSpy() {
-        var $visEl = getVisEl();
+        let $visEl = getVisEl();
         if (!$visEl) return;
 
         return ($visEl.height() < minVisChartHeight)
@@ -116,7 +116,7 @@ uiModules
       });
 
       $scope.$watch('vis', prereq(function (vis, oldVis) {
-        var $visEl = getVisEl();
+        let $visEl = getVisEl();
         if (!$visEl) return;
 
         if (!attr.editableVis) {
diff --git a/src/ui/public/visualize/visualize_legend.js b/src/ui/public/visualize/visualize_legend.js
index 36cd344bd89e3..b5a414f081608 100644
--- a/src/ui/public/visualize/visualize_legend.js
+++ b/src/ui/public/visualize/visualize_legend.js
@@ -11,16 +11,16 @@ import uiModules from 'ui/modules';
 
 uiModules.get('kibana')
 .directive('visualizeLegend', function (Private, getAppState) {
-  var Data = Private(VislibLibDataProvider);
-  var colorPalette = Private(VislibComponentsColorColorProvider);
-  var filterBarClickHandler = Private(FilterBarFilterBarClickHandlerProvider);
+  let Data = Private(VislibLibDataProvider);
+  let colorPalette = Private(VislibComponentsColorColorProvider);
+  let filterBarClickHandler = Private(FilterBarFilterBarClickHandlerProvider);
 
   return {
     restrict: 'E',
     template: html,
     link: function ($scope, $elem) {
-      var $state = getAppState();
-      var clickHandler = filterBarClickHandler($state);
+      let $state = getAppState();
+      let clickHandler = filterBarClickHandler($state);
       $scope.open = $scope.uiState.get('vis.legendOpen', true);
 
       $scope.$watch('renderbot.chartData', function (data) {
@@ -30,29 +30,29 @@ uiModules.get('kibana')
       });
 
       $scope.highlight = function (event) {
-        var el = event.currentTarget;
-        var handler = $scope.renderbot.vislibVis.handler;
+        let el = event.currentTarget;
+        let handler = $scope.renderbot.vislibVis.handler;
         if (!handler) return;
         handler.highlight.call(el, handler.el);
       };
 
       $scope.unhighlight = function (event) {
-        var el = event.currentTarget;
-        var handler = $scope.renderbot.vislibVis.handler;
+        let el = event.currentTarget;
+        let handler = $scope.renderbot.vislibVis.handler;
         if (!handler) return;
         handler.unHighlight.call(el, handler.el);
       };
 
       $scope.setColor = function (label, color) {
-        var colors = $scope.uiState.get('vis.colors') || {};
+        let colors = $scope.uiState.get('vis.colors') || {};
         colors[label] = color;
         $scope.uiState.set('vis.colors', colors);
         refresh();
       };
 
       $scope.toggleLegend = function () {
-        var bwcAddLegend = $scope.renderbot.vislibVis._attr.addLegend;
-        var bwcLegendStateDefault = bwcAddLegend == null ? true : bwcAddLegend;
+        let bwcAddLegend = $scope.renderbot.vislibVis._attr.addLegend;
+        let bwcLegendStateDefault = bwcAddLegend == null ? true : bwcAddLegend;
         $scope.open = !$scope.uiState.get('vis.legendOpen', bwcLegendStateDefault);
         $scope.uiState.set('vis.legendOpen', $scope.open);
       };
@@ -62,7 +62,7 @@ uiModules.get('kibana')
       };
 
       $scope.canFilter = function (legendData) {
-        var filters = clickHandler({point: legendData}, true) || [];
+        let filters = clickHandler({point: legendData}, true) || [];
         return filters.length;
       };
 
@@ -77,7 +77,7 @@ uiModules.get('kibana')
       ];
 
       function refresh() {
-        var vislibVis = $scope.renderbot.vislibVis;
+        let vislibVis = $scope.renderbot.vislibVis;
 
         if ($scope.uiState.get('vis.legendOpen') == null && vislibVis._attr.addLegend != null) {
           $scope.open = vislibVis._attr.addLegend;
@@ -96,7 +96,7 @@ uiModules.get('kibana')
       };
 
       function getSeriesLabels(data) {
-        var values = data.map(function (chart) {
+        let values = data.map(function (chart) {
           return chart.series;
         })
         .reduce(function (a, b) {
diff --git a/src/ui/public/watch_multi/watch_multi.js b/src/ui/public/watch_multi/watch_multi.js
index 5cfa391068572..279076eea4e8b 100644
--- a/src/ui/public/watch_multi/watch_multi.js
+++ b/src/ui/public/watch_multi/watch_multi.js
@@ -37,15 +37,15 @@ uiModules.get('kibana')
       if (!_.isArray(expressions)) throw new TypeError('expected an array of expressions to watch');
       if (!_.isFunction(fn)) throw new TypeError('expected a function that is triggered on each watch');
 
-      var $scope = this;
-      var vals = new Array(expressions.length);
-      var prev = new Array(expressions.length);
-      var fire = false;
-      var init = 0;
-      var neededInits = expressions.length;
+      let $scope = this;
+      let vals = new Array(expressions.length);
+      let prev = new Array(expressions.length);
+      let fire = false;
+      let init = 0;
+      let neededInits = expressions.length;
 
       // first, register all of the multi-watchers
-      var unwatchers = expressions.map(function (expr, i) {
+      let unwatchers = expressions.map(function (expr, i) {
         expr = normalizeExpression($scope, expr);
         if (!expr) return;
 
@@ -62,7 +62,7 @@ uiModules.get('kibana')
 
       // then, the watcher that checks to see if any of
       // the other watchers triggered this cycle
-      var flip = false;
+      let flip = false;
       unwatchers.push($scope.$watch(function () {
         if (init < neededInits) return init;
 
@@ -85,7 +85,7 @@ uiModules.get('kibana')
 
     function normalizeExpression($scope, expr) {
       if (!expr) return;
-      var norm = {
+      let norm = {
         fn: $scope.$watch,
         deep: false
       };