tslint: autofix of let -> const (#13033)

public/app/containers/AlertRuleList/AlertRuleList.test.tsx

@@ -46,7 +46,7 @@ describe('AlertRuleList', () => {
 
   it('should render 1 rule', () => {
     page.update();
-    let ruleNode = page.find('.alert-rule-item');
+    const ruleNode = page.find('.alert-rule-item');
     expect(toJson(ruleNode)).toMatchSnapshot();
   });
 

public/app/containers/AlertRuleList/AlertRuleList.tsx

@@ -132,13 +132,13 @@ export class AlertRuleItem extends React.Component<AlertRuleItemProps, any> {
   render() {
     const { rule } = this.props;
 
-    let stateClass = classNames({
+    const stateClass = classNames({
       fa: true,
       'fa-play': rule.isPaused,
       'fa-pause': !rule.isPaused,
     });
 
-    let ruleUrl = `${rule.url}?panelId=${rule.panelId}&fullscreen=true&edit=true&tab=alert`;
+    const ruleUrl = `${rule.url}?panelId=${rule.panelId}&fullscreen=true&edit=true&tab=alert`;
 
     return (
       <li className="alert-rule-item">

public/app/containers/Explore/Table.tsx

@@ -40,7 +40,7 @@ function Cell(props: SFCCellProps) {
 export default class Table extends PureComponent<TableProps, {}> {
   render() {
     const { className = '', data, loading, onClickCell } = this.props;
-    let tableModel = data || EMPTY_TABLE;
+    const tableModel = data || EMPTY_TABLE;
     if (!loading && data && data.rows.length === 0) {
       return (
         <table className={`${className} filter-table`}>

public/app/containers/Explore/utils/prometheus.ts

@@ -65,7 +65,7 @@ export function parseSelector(query: string, cursorOffset = 1): { labelKeys: any
 
   // Extract clean labels to form clean selector, incomplete labels are dropped
   const selector = query.slice(prefixOpen, suffixClose);
-  let labels = {};
+  const labels = {};
   selector.replace(labelRegexp, match => {
     const delimiterIndex = match.indexOf('=');
     const key = match.slice(0, delimiterIndex);

public/app/containers/Teams/TeamList.tsx

@@ -36,7 +36,7 @@ export class TeamList extends React.Component<Props, any> {
   };
 
   renderTeamMember(team: Team): JSX.Element {
-    let teamUrl = `org/teams/edit/${team.id}`;
+    const teamUrl = `org/teams/edit/${team.id}`;
 
     return (
       <tr key={team.id}>

public/app/core/components/Permissions/AddPermissions.test.tsx

@@ -22,7 +22,7 @@ describe('AddPermissions', () => {
   let wrapper;
   let store;
   let instance;
-  let backendSrv: any = getBackendSrv();
+  const backendSrv: any = getBackendSrv();
 
   beforeAll(() => {
     store = RootStore.create({}, { backendSrv: backendSrv });

public/app/core/components/TagFilter/TagFilter.tsx

@@ -43,7 +43,7 @@ export class TagFilter extends React.Component<Props, any> {
   }
 
   render() {
-    let selectOptions = {
+    const selectOptions = {
       loadOptions: this.searchTags,
       onChange: this.onChange,
       value: this.props.tags,

public/app/core/components/code_editor/code_editor.ts

@@ -53,23 +53,23 @@ const DEFAULT_TAB_SIZE = 2;
 const DEFAULT_BEHAVIOURS = true;
 const DEFAULT_SNIPPETS = true;
 
-let editorTemplate = `<div></div>`;
+const editorTemplate = `<div></div>`;
 
 function link(scope, elem, attrs) {
   // Options
-  let langMode = attrs.mode || DEFAULT_MODE;
-  let maxLines = attrs.maxLines || DEFAULT_MAX_LINES;
-  let showGutter = attrs.showGutter !== undefined;
-  let tabSize = attrs.tabSize || DEFAULT_TAB_SIZE;
-  let behavioursEnabled = attrs.behavioursEnabled ? attrs.behavioursEnabled === 'true' : DEFAULT_BEHAVIOURS;
-  let snippetsEnabled = attrs.snippetsEnabled ? attrs.snippetsEnabled === 'true' : DEFAULT_SNIPPETS;
+  const langMode = attrs.mode || DEFAULT_MODE;
+  const maxLines = attrs.maxLines || DEFAULT_MAX_LINES;
+  const showGutter = attrs.showGutter !== undefined;
+  const tabSize = attrs.tabSize || DEFAULT_TAB_SIZE;
+  const behavioursEnabled = attrs.behavioursEnabled ? attrs.behavioursEnabled === 'true' : DEFAULT_BEHAVIOURS;
+  const snippetsEnabled = attrs.snippetsEnabled ? attrs.snippetsEnabled === 'true' : DEFAULT_SNIPPETS;
 
   // Initialize editor
-  let aceElem = elem.get(0);
-  let codeEditor = ace.edit(aceElem);
-  let editorSession = codeEditor.getSession();
+  const aceElem = elem.get(0);
+  const codeEditor = ace.edit(aceElem);
+  const editorSession = codeEditor.getSession();
 
-  let editorOptions = {
+  const editorOptions = {
     maxLines: maxLines,
     showGutter: showGutter,
     tabSize: tabSize,
@@ -93,7 +93,7 @@ function link(scope, elem, attrs) {
 
   // Add classes
   elem.addClass('gf-code-editor');
-  let textarea = elem.find('textarea');
+  const textarea = elem.find('textarea');
   textarea.addClass('gf-form-input');
 
   if (scope.codeEditorFocus) {
@@ -110,14 +110,14 @@ function link(scope, elem, attrs) {
   // Event handlers
   editorSession.on('change', e => {
     scope.$apply(() => {
-      let newValue = codeEditor.getValue();
+      const newValue = codeEditor.getValue();
       scope.content = newValue;
     });
   });
 
   // Sync with outer scope - update editor content if model has been changed from outside of directive.
   scope.$watch('content', (newValue, oldValue) => {
-    let editorValue = codeEditor.getValue();
+    const editorValue = codeEditor.getValue();
     if (newValue !== editorValue && newValue !== oldValue) {
       scope.$$postDigest(function() {
         setEditorContent(newValue);
@@ -157,7 +157,7 @@ function link(scope, elem, attrs) {
       anyEditor.completers.push(scope.getCompleter());
     }
 
-    let aceModeName = `ace/mode/${lang}`;
+    const aceModeName = `ace/mode/${lang}`;
     editorSession.setMode(aceModeName);
   }
 

public/app/core/components/colorpicker/ColorPicker.tsx

@@ -29,10 +29,10 @@ export class ColorPicker extends React.Component<Props, any> {
   openColorPicker() {
     const dropContent = <ColorPickerPopover color={this.props.color} onColorSelect={this.onColorSelect} />;
 
-    let dropContentElem = document.createElement('div');
+    const dropContentElem = document.createElement('div');
     ReactDOM.render(dropContent, dropContentElem);
 
-    let drop = new Drop({
+    const drop = new Drop({
       target: this.pickerElem[0],
       content: dropContentElem,
       position: 'top center',

public/app/core/components/colorpicker/ColorPickerPopover.tsx

@@ -28,7 +28,7 @@ export class ColorPickerPopover extends React.Component<Props, any> {
   }
 
   setColor(color) {
-    let newColor = tinycolor(color);
+    const newColor = tinycolor(color);
     if (newColor.isValid()) {
       this.setState({
         color: newColor.toString(),
@@ -43,20 +43,20 @@ export class ColorPickerPopover extends React.Component<Props, any> {
   }
 
   spectrumColorSelected(color) {
-    let rgbColor = color.toRgbString();
+    const rgbColor = color.toRgbString();
     this.setColor(rgbColor);
   }
 
   onColorStringChange(e) {
-    let colorString = e.target.value;
+    const colorString = e.target.value;
     this.setState({
       colorString: colorString,
     });
 
-    let newColor = tinycolor(colorString);
+    const newColor = tinycolor(colorString);
     if (newColor.isValid()) {
       // Update only color state
-      let newColorString = newColor.toString();
+      const newColorString = newColor.toString();
       this.setState({
         color: newColorString,
       });
@@ -65,7 +65,7 @@ export class ColorPickerPopover extends React.Component<Props, any> {
   }
 
   onColorStringBlur(e) {
-    let colorString = e.target.value;
+    const colorString = e.target.value;
     this.setColor(colorString);
   }
 
@@ -73,7 +73,7 @@ export class ColorPickerPopover extends React.Component<Props, any> {
     this.pickerNavElem.find('li:first').addClass('active');
     this.pickerNavElem.on('show', e => {
       // use href attr (#name => name)
-      let tab = e.target.hash.slice(1);
+      const tab = e.target.hash.slice(1);
       this.setState({
         tab: tab,
       });

public/app/core/components/colorpicker/SpectrumPicker.tsx

@@ -29,7 +29,7 @@ export class SpectrumPicker extends React.Component<Props, any> {
   }
 
   componentDidMount() {
-    let spectrumOptions = _.assignIn(
+    const spectrumOptions = _.assignIn(
       {
         flat: true,
         showAlpha: true,

public/app/core/components/form_dropdown/form_dropdown.ts

@@ -132,7 +132,7 @@ export class FormDropdownCtrl {
       this.optionCache = options;
 
       // extract texts
-      let optionTexts = _.map(options, op => {
+      const optionTexts = _.map(options, op => {
         return _.escape(op.text);
       });
 

public/app/core/components/grafana_app.ts

@@ -140,7 +140,7 @@ export function grafanaAppDirective(playlistSrv, contextSrv, $timeout, $rootScop
         }
 
         // close all drops
-        for (let drop of Drop.drops) {
+        for (const drop of Drop.drops) {
           drop.destroy();
         }
       });

public/app/core/components/info_popover.ts

@@ -8,10 +8,10 @@ export function infoPopover() {
     template: '<i class="fa fa-info-circle"></i>',
     transclude: true,
     link: function(scope, elem, attrs, ctrl, transclude) {
-      let offset = attrs.offset || '0 -10px';
-      let position = attrs.position || 'right middle';
+      const offset = attrs.offset || '0 -10px';
+      const position = attrs.position || 'right middle';
       let classes = 'drop-help drop-hide-out-of-bounds';
-      let openOn = 'hover';
+      const openOn = 'hover';
 
       elem.addClass('gf-form-help-icon');
 
@@ -24,14 +24,14 @@ export function infoPopover() {
       }
 
       transclude(function(clone, newScope) {
-        let content = document.createElement('div');
+        const content = document.createElement('div');
         content.className = 'markdown-html';
 
         _.each(clone, node => {
           content.appendChild(node);
         });
 
-        let dropOptions = {
+        const dropOptions = {
           target: elem[0],
           content: content,
           position: position,
@@ -52,9 +52,9 @@ export function infoPopover() {
 
         // Create drop in next digest after directive content is rendered.
         scope.$applyAsync(() => {
-          let drop = new Drop(dropOptions);
+          const drop = new Drop(dropOptions);
 
-          let unbind = scope.$on('$destroy', function() {
+          const unbind = scope.$on('$destroy', function() {
             drop.destroy();
             unbind();
           });

public/app/core/components/manage_dashboards/manage_dashboards.ts

@@ -103,10 +103,10 @@ export class ManageDashboardsCtrl {
 
     this.sections = result;
 
-    for (let section of this.sections) {
+    for (const section of this.sections) {
       section.checked = false;
 
-      for (let dashboard of section.items) {
+      for (const dashboard of section.items) {
         dashboard.checked = false;
       }
     }
@@ -119,7 +119,7 @@ export class ManageDashboardsCtrl {
   selectionChanged() {
     let selectedDashboards = 0;
 
-    for (let section of this.sections) {
+    for (const section of this.sections) {
       selectedDashboards += _.filter(section.items, { checked: true }).length;
     }
 
@@ -129,7 +129,7 @@ export class ManageDashboardsCtrl {
   }
 
   getFoldersAndDashboardsToDelete() {
-    let selectedDashboards = {
+    const selectedDashboards = {
       folders: [],
       dashboards: [],
     };
@@ -148,7 +148,7 @@ export class ManageDashboardsCtrl {
 
   getFolderIds(sections) {
     const ids = [];
-    for (let s of sections) {
+    for (const s of sections) {
       if (s.checked) {
         ids.push(s.id);
       }
@@ -191,7 +191,7 @@ export class ManageDashboardsCtrl {
   }
 
   getDashboardsToMove() {
-    let selectedDashboards = [];
+    const selectedDashboards = [];
 
     for (const section of this.sections) {
       const selected = _.filter(section.items, { checked: true });
@@ -264,7 +264,7 @@ export class ManageDashboardsCtrl {
   }
 
   onSelectAllChanged() {
-    for (let section of this.sections) {
+    for (const section of this.sections) {
       if (!section.hideHeader) {
         section.checked = this.selectAllChecked;
       }

public/app/core/components/scroll/scroll.ts

@@ -17,7 +17,7 @@ export function geminiScrollbar() {
     restrict: 'A',
     link: function(scope, elem, attrs) {
       let scrollRoot = elem.parent();
-      let scroller = elem;
+      const scroller = elem;
 
       if (attrs.grafanaScrollbar && attrs.grafanaScrollbar === 'scrollonroot') {
         scrollRoot = scroller;
@@ -27,7 +27,7 @@ export function geminiScrollbar() {
       $(scrollBarHTML).appendTo(scrollRoot);
       elem.addClass(scrollerClass);
 
-      let scrollParams = {
+      const scrollParams = {
         root: scrollRoot[0],
         scroller: scroller[0],
         bar: '.baron__bar',
@@ -37,7 +37,7 @@ export function geminiScrollbar() {
         direction: 'v',
       };
 
-      let scrollbar = baron(scrollParams);
+      const scrollbar = baron(scrollParams);
 
       let lastPos = 0;
 

public/app/core/components/search/SearchResult.tsx

@@ -54,7 +54,7 @@ export class SearchResultSection extends React.Component<SectionProps, any> {
   };
 
   render() {
-    let collapseClassNames = classNames({
+    const collapseClassNames = classNames({
       fa: true,
       'fa-plus': !this.props.section.expanded,
       'fa-minus': this.props.section.expanded,

public/app/core/components/sidemenu/sidemenu.ts

@@ -17,13 +17,13 @@ export class SideMenuCtrl {
     this.isSignedIn = contextSrv.isSignedIn;
     this.user = contextSrv.user;
 
-    let navTree = _.cloneDeep(config.bootData.navTree);
+    const navTree = _.cloneDeep(config.bootData.navTree);
     this.mainLinks = _.filter(navTree, item => !item.hideFromMenu);
     this.bottomNav = _.filter(navTree, item => item.hideFromMenu);
     this.loginUrl = 'login?redirect=' + encodeURIComponent(this.$location.path());
 
     if (contextSrv.user.orgCount > 1) {
-      let profileNode = _.find(this.bottomNav, { id: 'profile' });
+      const profileNode = _.find(this.bottomNav, { id: 'profile' });
       if (profileNode) {
         profileNode.showOrgSwitcher = true;
       }

public/app/core/controllers/login_ctrl.ts

@@ -45,8 +45,8 @@ export class LoginCtrl {
     };
 
     $scope.changeView = function() {
-      let loginView = document.querySelector('#login-view');
-      let changePasswordView = document.querySelector('#change-password-view');
+      const loginView = document.querySelector('#login-view');
+      const changePasswordView = document.querySelector('#change-password-view');
 
       loginView.className += ' add';
       setTimeout(() => {

public/app/core/directives/dropdown_typeahead.ts

@@ -4,12 +4,12 @@ import coreModule from '../core_module';
 
 /** @ngInject */
 export function dropdownTypeahead($compile) {
-  let inputTemplate =
+  const inputTemplate =
     '<input type="text"' +
     ' class="gf-form-input input-medium tight-form-input"' +
     ' spellcheck="false" style="display:none"></input>';
 
-  let buttonTemplate =
+  const buttonTemplate =
     '<a class="gf-form-label tight-form-func dropdown-toggle"' +
     ' tabindex="1" gf-dropdown="menuItems" data-toggle="dropdown"' +
     ' data-placement="top"><i class="fa fa-plus"></i></a>';
@@ -21,8 +21,8 @@ export function dropdownTypeahead($compile) {
       model: '=ngModel',
     },
     link: function($scope, elem, attrs) {
-      let $input = $(inputTemplate);
-      let $button = $(buttonTemplate);
+      const $input = $(inputTemplate);
+      const $button = $(buttonTemplate);
       $input.appendTo(elem);
       $button.appendTo(elem);
 
@@ -42,7 +42,7 @@ export function dropdownTypeahead($compile) {
         });
       }
 
-      let typeaheadValues = _.reduce(
+      const typeaheadValues = _.reduce(
         $scope.menuItems,
         function(memo, value, index) {
           if (!value.submenu) {
@@ -60,8 +60,8 @@ export function dropdownTypeahead($compile) {
       );
 
       $scope.menuItemSelected = function(index, subIndex) {
-        let menuItem = $scope.menuItems[index];
-        let payload: any = { $item: menuItem };
+        const menuItem = $scope.menuItems[index];
+        const payload: any = { $item: menuItem };
         if (menuItem.submenu && subIndex !== void 0) {
           payload.$subItem = menuItem.submenu[subIndex];
         }
@@ -74,7 +74,7 @@ export function dropdownTypeahead($compile) {
         minLength: 1,
         items: 10,
         updater: function(value) {
-          let result: any = {};
+          const result: any = {};
           _.each($scope.menuItems, function(menuItem) {
             _.each(menuItem.submenu, function(submenuItem) {
               if (value === menuItem.text + ' ' + submenuItem.text) {
@@ -124,10 +124,10 @@ export function dropdownTypeahead($compile) {
 
 /** @ngInject */
 export function dropdownTypeahead2($compile) {
-  let inputTemplate =
+  const inputTemplate =
     '<input type="text"' + ' class="gf-form-input"' + ' spellcheck="false" style="display:none"></input>';
 
-  let buttonTemplate =
+  const buttonTemplate =
     '<a class="gf-form-input dropdown-toggle"' +
     ' tabindex="1" gf-dropdown="menuItems" data-toggle="dropdown"' +
     ' data-placement="top"><i class="fa fa-plus"></i></a>';
@@ -139,8 +139,8 @@ export function dropdownTypeahead2($compile) {
       model: '=ngModel',
     },
     link: function($scope, elem, attrs) {
-      let $input = $(inputTemplate);
-      let $button = $(buttonTemplate);
+      const $input = $(inputTemplate);
+      const $button = $(buttonTemplate);
       $input.appendTo(elem);
       $button.appendTo(elem);
 
@@ -160,7 +160,7 @@ export function dropdownTypeahead2($compile) {
         });
       }
 
-      let typeaheadValues = _.reduce(
+      const typeaheadValues = _.reduce(
         $scope.menuItems,
         function(memo, value, index) {
           if (!value.submenu) {
@@ -178,8 +178,8 @@ export function dropdownTypeahead2($compile) {
       );
 
       $scope.menuItemSelected = function(index, subIndex) {
-        let menuItem = $scope.menuItems[index];
-        let payload: any = { $item: menuItem };
+        const menuItem = $scope.menuItems[index];
+        const payload: any = { $item: menuItem };
         if (menuItem.submenu && subIndex !== void 0) {
           payload.$subItem = menuItem.submenu[subIndex];
         }
@@ -192,7 +192,7 @@ export function dropdownTypeahead2($compile) {
         minLength: 1,
         items: 10,
         updater: function(value) {
-          let result: any = {};
+          const result: any = {};
           _.each($scope.menuItems, function(menuItem) {
             _.each(menuItem.submenu, function(submenuItem) {
               if (value === menuItem.text + ' ' + submenuItem.text) {

public/app/core/directives/metric_segment.ts

@@ -4,16 +4,16 @@ import coreModule from '../core_module';
 
 /** @ngInject */
 export function metricSegment($compile, $sce) {
-  let inputTemplate =
+  const inputTemplate =
     '<input type="text" data-provide="typeahead" ' +
     ' class="gf-form-input input-medium"' +
     ' spellcheck="false" style="display:none"></input>';
 
-  let linkTemplate =
+  const linkTemplate =
     '<a class="gf-form-label" ng-class="segment.cssClass" ' +
     'tabindex="1" give-focus="segment.focus" ng-bind-html="segment.html"></a>';
 
-  let selectTemplate =
+  const selectTemplate =
     '<a class="gf-form-input gf-form-input--dropdown" ng-class="segment.cssClass" ' +
     'tabindex="1" give-focus="segment.focus" ng-bind-html="segment.html"></a>';
 
@@ -25,13 +25,13 @@ export function metricSegment($compile, $sce) {
       debounce: '@',
     },
     link: function($scope, elem) {
-      let $input = $(inputTemplate);
-      let segment = $scope.segment;
-      let $button = $(segment.selectMode ? selectTemplate : linkTemplate);
+      const $input = $(inputTemplate);
+      const segment = $scope.segment;
+      const $button = $(segment.selectMode ? selectTemplate : linkTemplate);
       let options = null;
       let cancelBlur = null;
       let linkMode = true;
-      let debounceLookup = $scope.debounce;
+      const debounceLookup = $scope.debounce;
 
       $input.appendTo(elem);
       $button.appendTo(elem);
@@ -44,7 +44,7 @@ export function metricSegment($compile, $sce) {
         value = _.unescape(value);
 
         $scope.$apply(function() {
-          let selected = _.find($scope.altSegments, { value: value });
+          const selected = _.find($scope.altSegments, { value: value });
           if (selected) {
             segment.value = selected.value;
             segment.html = selected.html || selected.value;
@@ -141,10 +141,10 @@ export function metricSegment($compile, $sce) {
         matcher: $scope.matcher,
       });
 
-      let typeahead = $input.data('typeahead');
+      const typeahead = $input.data('typeahead');
       typeahead.lookup = function() {
         this.query = this.$element.val() || '';
-        let items = this.source(this.query, $.proxy(this.process, this));
+        const items = this.source(this.query, $.proxy(this.process, this));
         return items ? this.process(items) : items;
       };
 
@@ -169,7 +169,7 @@ export function metricSegment($compile, $sce) {
 
         linkMode = false;
 
-        let typeahead = $input.data('typeahead');
+        const typeahead = $input.data('typeahead');
         if (typeahead) {
           $input.val('');
           typeahead.lookup();
@@ -200,8 +200,8 @@ export function metricSegmentModel(uiSegmentSrv, $q) {
         let cachedOptions;
 
         $scope.valueToSegment = function(value) {
-          let option = _.find($scope.options, { value: value });
-          let segment = {
+          const option = _.find($scope.options, { value: value });
+          const segment = {
             cssClass: attrs.cssClass,
             custom: attrs.custom,
             value: option ? option.text : value,
@@ -234,7 +234,7 @@ export function metricSegmentModel(uiSegmentSrv, $q) {
 
         $scope.onSegmentChange = function() {
           if (cachedOptions) {
-            let option = _.find(cachedOptions, { text: $scope.segment.value });
+            const option = _.find(cachedOptions, { text: $scope.segment.value });
             if (option && option.value !== $scope.property) {
               $scope.property = option.value;
             } else if (attrs.custom !== 'false') {

public/app/core/directives/misc.ts

@@ -156,7 +156,7 @@ function gfDropdown($parse, $compile, $timeout) {
     var ul = ['<ul class="dropdown-menu ' + upclass + '" role="menu" aria-labelledby="drop1">', '</ul>'];
 
     for (let index = 0; index < items.length; index++) {
-      let item = items[index];
+      const item = items[index];
 
       if (item.divider) {
         ul.splice(index + 1, 0, '<li class="divider"></li>');

public/app/core/directives/value_select_dropdown.ts

@@ -46,16 +46,16 @@ export class ValueSelectDropdownCtrl {
   }
 
   updateLinkText() {
-    let current = this.variable.current;
+    const current = this.variable.current;
 
     if (current.tags && current.tags.length) {
       // filer out values that are in selected tags
-      let selectedAndNotInTag = _.filter(this.variable.options, option => {
+      const selectedAndNotInTag = _.filter(this.variable.options, option => {
         if (!option.selected) {
           return false;
         }
         for (let i = 0; i < current.tags.length; i++) {
-          let tag = current.tags[i];
+          const tag = current.tags[i];
           if (_.indexOf(tag.values, option.value) !== -1) {
             return false;
           }
@@ -64,7 +64,7 @@ export class ValueSelectDropdownCtrl {
       });
 
       // convert values to text
-      let currentTexts = _.map(selectedAndNotInTag, 'text');
+      const currentTexts = _.map(selectedAndNotInTag, 'text');
 
       // join texts
       this.linkText = currentTexts.join(' + ');
@@ -142,7 +142,7 @@ export class ValueSelectDropdownCtrl {
     commitChange = commitChange || false;
     excludeOthers = excludeOthers || false;
 
-    let setAllExceptCurrentTo = newValue => {
+    const setAllExceptCurrentTo = newValue => {
       _.each(this.options, other => {
         if (option !== other) {
           other.selected = newValue;
@@ -246,9 +246,9 @@ export function valueSelectDropdown($compile, $window, $timeout, $rootScope) {
     controllerAs: 'vm',
     bindToController: true,
     link: function(scope, elem) {
-      let bodyEl = angular.element($window.document.body);
-      let linkEl = elem.find('.variable-value-link');
-      let inputEl = elem.find('input');
+      const bodyEl = angular.element($window.document.body);
+      const linkEl = elem.find('.variable-value-link');
+      const inputEl = elem.find('input');
 
       function openDropdown() {
         inputEl.css('width', Math.max(linkEl.width(), 80) + 'px');
@@ -288,7 +288,7 @@ export function valueSelectDropdown($compile, $window, $timeout, $rootScope) {
         }
       });
 
-      let cleanUp = $rootScope.$on('template-variable-value-updated', () => {
+      const cleanUp = $rootScope.$on('template-variable-value-updated', () => {
         scope.vm.updateLinkText();
       });
 

public/app/core/nav_model_srv.ts

@@ -41,14 +41,14 @@ export class NavModelSrv {
     var children = this.navItems;
     var nav = new NavModel();
 
-    for (let id of args) {
+    for (const id of args) {
       // if its a number then it's the index to use for main
       if (_.isNumber(id)) {
         nav.main = nav.breadcrumbs[id];
         break;
       }
 
-      let node = _.find(children, { id: id });
+      const node = _.find(children, { id: id });
       nav.breadcrumbs.push(node);
       nav.node = node;
       nav.main = node;
@@ -56,7 +56,7 @@ export class NavModelSrv {
     }
 
     if (nav.main.children) {
-      for (let item of nav.main.children) {
+      for (const item of nav.main.children) {
         item.active = false;
 
         if (item.url === nav.node.url) {

public/app/core/services/backend_srv.ts

@@ -276,11 +276,11 @@ export class BackendSrv {
   deleteFoldersAndDashboards(folderUids, dashboardUids) {
     const tasks = [];
 
-    for (let folderUid of folderUids) {
+    for (const folderUid of folderUids) {
       tasks.push(this.createTask(this.deleteFolder.bind(this), true, folderUid, true));
     }
 
-    for (let dashboardUid of dashboardUids) {
+    for (const dashboardUid of dashboardUids) {
       tasks.push(this.createTask(this.deleteDashboard.bind(this), true, dashboardUid, true));
     }
 
@@ -290,7 +290,7 @@ export class BackendSrv {
   moveDashboards(dashboardUids, toFolder) {
     const tasks = [];
 
-    for (let uid of dashboardUids) {
+    for (const uid of dashboardUids) {
       tasks.push(this.createTask(this.moveDashboard.bind(this), true, uid, toFolder));
     }
 
@@ -304,7 +304,7 @@ export class BackendSrv {
   }
 
   private moveDashboard(uid, toFolder) {
-    let deferred = this.$q.defer();
+    const deferred = this.$q.defer();
 
     this.getDashboardByUid(uid).then(fullDash => {
       const model = new DashboardModel(fullDash.dashboard, fullDash.meta);
@@ -315,7 +315,7 @@ export class BackendSrv {
       }
 
       const clone = model.getSaveModelClone();
-      let options = {
+      const options = {
         folderId: toFolder.id,
         overwrite: false,
       };

public/app/core/services/bridge_srv.ts

@@ -15,7 +15,7 @@ export class BridgeSrv {
 
   init() {
     this.$rootScope.$on('$routeUpdate', (evt, data) => {
-      let angularUrl = this.$location.url();
+      const angularUrl = this.$location.url();
       if (store.view.currentUrl !== angularUrl) {
         store.view.updatePathAndQuery(this.$location.path(), this.$location.search(), this.$route.current.params);
       }
@@ -28,7 +28,7 @@ export class BridgeSrv {
     reaction(
       () => store.view.currentUrl,
       currentUrl => {
-        let angularUrl = this.$location.url();
+        const angularUrl = this.$location.url();
         const url = locationUtil.stripBaseFromUrl(currentUrl);
         if (angularUrl !== url) {
           this.$timeout(() => {

public/app/core/services/dynamic_directive_srv.ts

@@ -36,7 +36,7 @@ class DynamicDirectiveSrv {
   }
 
   create(options) {
-    let directiveDef = {
+    const directiveDef = {
       restrict: 'E',
       scope: options.scope,
       link: (scope, elem, attrs) => {

public/app/core/services/keybindingSrv.ts

@@ -210,7 +210,7 @@ export class KeybindingSrv {
     // duplicate panel
     this.bind('p d', () => {
       if (dashboard.meta.focusPanelId && dashboard.meta.canEdit) {
-        let panelIndex = dashboard.getPanelInfoById(dashboard.meta.focusPanelId).index;
+        const panelIndex = dashboard.getPanelInfoById(dashboard.meta.focusPanelId).index;
         dashboard.duplicatePanel(dashboard.panels[panelIndex]);
       }
     });

public/app/core/services/ng_react.ts

@@ -295,6 +295,6 @@ var reactDirective = function($injector) {
   };
 };
 
-let ngModule = angular.module('react', []);
+const ngModule = angular.module('react', []);
 ngModule.directive('reactComponent', ['$injector', reactComponent]);
 ngModule.factory('reactDirective', ['$injector', reactDirective]);

public/app/core/services/search_srv.ts

@@ -85,10 +85,10 @@ export class SearchSrv {
   }
 
   search(options) {
-    let sections: any = {};
-    let promises = [];
-    let query = _.clone(options);
-    let hasFilters =
+    const sections: any = {};
+    const promises = [];
+    const query = _.clone(options);
+    const hasFilters =
       options.query ||
       (options.tag && options.tag.length > 0) ||
       options.starred ||
@@ -124,7 +124,7 @@ export class SearchSrv {
     }
 
     // create folder index
-    for (let hit of results) {
+    for (const hit of results) {
       if (hit.type === 'dash-folder') {
         sections[hit.id] = {
           id: hit.id,
@@ -140,7 +140,7 @@ export class SearchSrv {
       }
     }
 
-    for (let hit of results) {
+    for (const hit of results) {
       if (hit.type === 'dash-folder') {
         continue;
       }
@@ -185,7 +185,7 @@ export class SearchSrv {
       return Promise.resolve(section);
     }
 
-    let query = {
+    const query = {
       folderIds: [section.id],
     };
 

public/app/core/services/segment_srv.ts

@@ -3,7 +3,7 @@ import coreModule from '../core_module';
 
 /** @ngInject */
 export function uiSegmentSrv($sce, templateSrv) {
-  let self = this;
+  const self = this;
 
   function MetricSegment(options) {
     if (options === '*' || options.value === '*') {
@@ -78,7 +78,7 @@ export function uiSegmentSrv($sce, templateSrv) {
 
   this.transformToSegments = function(addTemplateVars, variableTypeFilter) {
     return function(results) {
-      let segments = _.map(results, function(segment) {
+      const segments = _.map(results, function(segment) {
         return self.newSegment({ value: segment.text, expandable: segment.expandable });
       });
 

public/app/core/specs/backend_srv.test.ts

@@ -2,14 +2,14 @@ import { BackendSrv } from 'app/core/services/backend_srv';
 jest.mock('app/core/store');
 
 describe('backend_srv', function() {
-  let _httpBackend = options => {
+  const _httpBackend = options => {
     if (options.url === 'gateway-error') {
       return Promise.reject({ status: 502 });
     }
     return Promise.resolve({});
   };
 
-  let _backendSrv = new BackendSrv(_httpBackend, {}, {}, {}, {});
+  const _backendSrv = new BackendSrv(_httpBackend, {}, {}, {}, {});
 
   describe('when handling errors', () => {
     it('should return the http status code', async () => {

public/app/core/specs/file_export.test.ts

@@ -2,7 +2,7 @@ import * as fileExport from '../utils/file_export';
 import { beforeEach, expect } from 'test/lib/common';
 
 describe('file_export', () => {
-  let ctx: any = {};
+  const ctx: any = {};
 
   beforeEach(() => {
     ctx.seriesList = [
@@ -28,7 +28,7 @@ describe('file_export', () => {
 
   describe('when exporting series as rows', () => {
     it('should export points in proper order', () => {
-      let text = fileExport.convertSeriesListToCsv(ctx.seriesList, ctx.timeFormat);
+      const text = fileExport.convertSeriesListToCsv(ctx.seriesList, ctx.timeFormat);
       const expectedText =
         '"Series";"Time";"Value"\r\n' +
         '"series_1";"1500026100";1\r\n' +
@@ -48,7 +48,7 @@ describe('file_export', () => {
 
   describe('when exporting series as columns', () => {
     it('should export points in proper order', () => {
-      let text = fileExport.convertSeriesListToCsvColumns(ctx.seriesList, ctx.timeFormat);
+      const text = fileExport.convertSeriesListToCsvColumns(ctx.seriesList, ctx.timeFormat);
       const expectedText =
         '"Time";"series_1";"series_2"\r\n' +
         '"1500026100";1;11\r\n' +

public/app/core/specs/search.test.ts

@@ -12,7 +12,7 @@ describe('SearchCtrl', () => {
     search: (options: any) => {},
     getDashboardTags: () => {},
   };
-  let ctrl = new SearchCtrl({ $on: () => {} }, {}, {}, <SearchSrv>searchSrvStub);
+  const ctrl = new SearchCtrl({ $on: () => {} }, {}, {}, <SearchSrv>searchSrvStub);
 
   describe('Given an empty result', () => {
     beforeEach(() => {

public/app/core/specs/search_results.test.ts

@@ -12,7 +12,7 @@ describe('SearchResultsCtrl', () => {
   let ctrl;
 
   describe('when checking an item that is not checked', () => {
-    let item = { checked: false };
+    const item = { checked: false };
     let selectionChanged = false;
 
     beforeEach(() => {
@@ -31,7 +31,7 @@ describe('SearchResultsCtrl', () => {
   });
 
   describe('when checking an item that is checked', () => {
-    let item = { checked: true };
+    const item = { checked: true };
     let selectionChanged = false;
 
     beforeEach(() => {
@@ -72,7 +72,7 @@ describe('SearchResultsCtrl', () => {
         folderExpanded = true;
       };
 
-      let folder = {
+      const folder = {
         expanded: false,
         toggle: () => Promise.resolve(folder),
       };
@@ -94,7 +94,7 @@ describe('SearchResultsCtrl', () => {
         folderExpanded = true;
       };
 
-      let folder = {
+      const folder = {
         expanded: true,
         toggle: () => Promise.resolve(folder),
       };

public/app/core/specs/ticks.test.ts

@@ -2,7 +2,7 @@ import * as ticks from '../utils/ticks';
 
 describe('ticks', () => {
   describe('getFlotTickDecimals()', () => {
-    let ctx: any = {};
+    const ctx: any = {};
 
     beforeEach(() => {
       ctx.axis = {};

public/app/core/specs/time_series.test.ts

@@ -329,7 +329,7 @@ describe('TimeSeries', function() {
 
   describe('legend decimals', function() {
     let series, panel;
-    let height = 200;
+    const height = 200;
     beforeEach(function() {
       testData = {
         alias: 'test',
@@ -348,7 +348,7 @@ describe('TimeSeries', function() {
     });
 
     it('should set decimals based on Y axis (expect calculated decimals = 1)', function() {
-      let data = [series];
+      const data = [series];
       // Expect ticks with this data will have decimals = 1
       updateLegendValues(data, panel, height);
       expect(data[0].decimals).toBe(2);
@@ -358,21 +358,21 @@ describe('TimeSeries', function() {
       testData.datapoints = [[10, 2], [0, 3], [100, 4], [80, 5]];
       series = new TimeSeries(testData);
       series.getFlotPairs();
-      let data = [series];
+      const data = [series];
       updateLegendValues(data, panel, height);
       expect(data[0].decimals).toBe(0);
     });
 
     it('should set decimals to Y axis decimals + 1', function() {
       panel.yaxes[0].decimals = 2;
-      let data = [series];
+      const data = [series];
       updateLegendValues(data, panel, height);
       expect(data[0].decimals).toBe(3);
     });
 
     it('should set decimals to legend decimals value if it was set explicitly', function() {
       panel.decimals = 3;
-      let data = [series];
+      const data = [series];
       updateLegendValues(data, panel, height);
       expect(data[0].decimals).toBe(3);
     });

public/app/core/specs/value_select_dropdown.test.ts

@@ -3,7 +3,7 @@ import { ValueSelectDropdownCtrl } from '../directives/value_select_dropdown';
 import q from 'q';
 
 describe('SelectDropdownCtrl', () => {
-  let tagValuesMap: any = {};
+  const tagValuesMap: any = {};
 
   ValueSelectDropdownCtrl.prototype.onUpdated = jest.fn();
   let ctrl;

public/app/core/time_series2.ts

@@ -27,11 +27,11 @@ function translateFillOption(fill) {
  */
 export function updateLegendValues(data: TimeSeries[], panel, height) {
   for (let i = 0; i < data.length; i++) {
-    let series = data[i];
+    const series = data[i];
     const yaxes = panel.yaxes;
     const seriesYAxis = series.yaxis || 1;
     const axis = yaxes[seriesYAxis - 1];
-    let formater = kbn.valueFormats[axis.format];
+    const formater = kbn.valueFormats[axis.format];
 
     // decimal override
     if (_.isNumber(panel.decimals)) {
@@ -54,7 +54,7 @@ export function getDataMinMax(data: TimeSeries[]) {
   let datamin = null;
   let datamax = null;
 
-  for (let series of data) {
+  for (const series of data) {
     if (datamax === null || datamax < series.stats.max) {
       datamax = series.stats.max;
     }
@@ -225,7 +225,7 @@ export default class TimeSeries {
       // Due to missing values we could have different timeStep all along the series
       // so we have to find the minimum one (could occur with aggregators such as ZimSum)
       if (previousTime !== undefined) {
-        let timeStep = currentTime - previousTime;
+        const timeStep = currentTime - previousTime;
         if (timeStep < this.stats.timeStep) {
           this.stats.timeStep = timeStep;
         }

public/app/core/utils/colors.ts

@@ -9,7 +9,7 @@ export const ALERTING_COLOR = 'rgba(237, 46, 24, 1)';
 export const NO_DATA_COLOR = 'rgba(150, 150, 150, 1)';
 export const REGION_FILL_ALPHA = 0.09;
 
-let colors = [
+const colors = [
   '#7EB26D',
   '#EAB839',
   '#6ED0E0',
@@ -69,7 +69,7 @@ let colors = [
 ];
 
 export function sortColorsByHue(hexColors) {
-  let hslColors = _.map(hexColors, hexToHsl);
+  const hslColors = _.map(hexColors, hexToHsl);
 
   let sortedHSLColors = _.sortBy(hslColors, ['h']);
   sortedHSLColors = _.chunk(sortedHSLColors, PALETTE_ROWS);

public/app/core/utils/dag.test.ts

@@ -2,16 +2,16 @@ import { Graph } from './dag';
 
 describe('Directed acyclic graph', () => {
   describe('Given a graph with nodes with different links in between them', () => {
-    let dag = new Graph();
-    let nodeA = dag.createNode('A');
-    let nodeB = dag.createNode('B');
-    let nodeC = dag.createNode('C');
-    let nodeD = dag.createNode('D');
-    let nodeE = dag.createNode('E');
-    let nodeF = dag.createNode('F');
-    let nodeG = dag.createNode('G');
-    let nodeH = dag.createNode('H');
-    let nodeI = dag.createNode('I');
+    const dag = new Graph();
+    const nodeA = dag.createNode('A');
+    const nodeB = dag.createNode('B');
+    const nodeC = dag.createNode('C');
+    const nodeD = dag.createNode('D');
+    const nodeE = dag.createNode('E');
+    const nodeF = dag.createNode('F');
+    const nodeG = dag.createNode('G');
+    const nodeH = dag.createNode('H');
+    const nodeI = dag.createNode('I');
     dag.link([nodeB, nodeC, nodeD, nodeE, nodeF, nodeG, nodeH], nodeA);
     dag.link([nodeC, nodeD, nodeE, nodeF, nodeI], nodeB);
     dag.link([nodeD, nodeE, nodeF, nodeG], nodeC);

public/app/core/utils/dag.ts

@@ -26,8 +26,8 @@ export class Edge {
 
   unlink() {
     let pos;
-    let inode = this.inputNode;
-    let onode = this.outputNode;
+    const inode = this.inputNode;
+    const onode = this.outputNode;
 
     if (!(inode && onode)) {
       return;
@@ -96,12 +96,12 @@ export class Node {
   }
 
   getOptimizedInputEdges(): Edge[] {
-    let toBeRemoved = [];
+    const toBeRemoved = [];
     this.inputEdges.forEach(e => {
-      let inputEdgesNodes = e.inputNode.inputEdges.map(e => e.inputNode);
+      const inputEdgesNodes = e.inputNode.inputEdges.map(e => e.inputNode);
 
       inputEdgesNodes.forEach(n => {
-        let edgeToRemove = n.getEdgeTo(this.name);
+        const edgeToRemove = n.getEdgeTo(this.name);
         if (edgeToRemove) {
           toBeRemoved.push(edgeToRemove);
         }
@@ -124,7 +124,7 @@ export class Graph {
   }
 
   createNodes(names: string[]): Node[] {
-    let nodes = [];
+    const nodes = [];
     names.forEach(name => {
       nodes.push(this.createNode(name));
     });
@@ -134,8 +134,8 @@ export class Graph {
   link(input: string | string[] | Node | Node[], output: string | string[] | Node | Node[]): Edge[] {
     let inputArr = [];
     let outputArr = [];
-    let inputNodes = [];
-    let outputNodes = [];
+    const inputNodes = [];
+    const outputNodes = [];
 
     if (input instanceof Array) {
       inputArr = input;
@@ -167,7 +167,7 @@ export class Graph {
       }
     }
 
-    let edges = [];
+    const edges = [];
     inputNodes.forEach(input => {
       outputNodes.forEach(output => {
         edges.push(this.createEdge().link(input, output));

public/app/core/utils/file_export.ts

@@ -74,7 +74,7 @@ export function convertSeriesListToCsv(seriesList, dateTimeFormat = DEFAULT_DATE
 }
 
 export function exportSeriesListToCsv(seriesList, dateTimeFormat = DEFAULT_DATETIME_FORMAT, excel = false) {
-  let text = convertSeriesListToCsv(seriesList, dateTimeFormat, excel);
+  const text = convertSeriesListToCsv(seriesList, dateTimeFormat, excel);
   saveSaveBlob(text, EXPORT_FILENAME);
 }
 
@@ -115,7 +115,7 @@ export function convertSeriesListToCsvColumns(seriesList, dateTimeFormat = DEFAU
 function mergeSeriesByTime(seriesList) {
   let timestamps = [];
   for (let i = 0; i < seriesList.length; i++) {
-    let seriesPoints = seriesList[i].datapoints;
+    const seriesPoints = seriesList[i].datapoints;
     for (let j = 0; j < seriesPoints.length; j++) {
       timestamps.push(seriesPoints[j][POINT_TIME_INDEX]);
     }
@@ -123,9 +123,9 @@ function mergeSeriesByTime(seriesList) {
   timestamps = sortedUniq(timestamps.sort());
 
   for (let i = 0; i < seriesList.length; i++) {
-    let seriesPoints = seriesList[i].datapoints;
-    let seriesTimestamps = seriesPoints.map(p => p[POINT_TIME_INDEX]);
-    let extendedSeries = [];
+    const seriesPoints = seriesList[i].datapoints;
+    const seriesTimestamps = seriesPoints.map(p => p[POINT_TIME_INDEX]);
+    const extendedSeries = [];
     let pointIndex;
     for (let j = 0; j < timestamps.length; j++) {
       pointIndex = sortedIndexOf(seriesTimestamps, timestamps[j]);
@@ -141,7 +141,7 @@ function mergeSeriesByTime(seriesList) {
 }
 
 export function exportSeriesListToCsvColumns(seriesList, dateTimeFormat = DEFAULT_DATETIME_FORMAT, excel = false) {
-  let text = convertSeriesListToCsvColumns(seriesList, dateTimeFormat, excel);
+  const text = convertSeriesListToCsvColumns(seriesList, dateTimeFormat, excel);
   saveSaveBlob(text, EXPORT_FILENAME);
 }
 
@@ -157,11 +157,11 @@ export function convertTableDataToCsv(table, excel = false) {
 }
 
 export function exportTableDataToCsv(table, excel = false) {
-  let text = convertTableDataToCsv(table, excel);
+  const text = convertTableDataToCsv(table, excel);
   saveSaveBlob(text, EXPORT_FILENAME);
 }
 
 export function saveSaveBlob(payload, fname) {
-  let blob = new Blob([payload], { type: 'text/csv;charset=utf-8;header=present;' });
+  const blob = new Blob([payload], { type: 'text/csv;charset=utf-8;header=present;' });
   saveAs(blob, fname);
 }

public/app/core/utils/outline.ts

@@ -1,6 +1,6 @@
 // based on http://www.paciellogroup.com/blog/2012/04/how-to-remove-css-outlines-in-an-accessible-manner/
 function outlineFixer() {
-  let d: any = document;
+  const d: any = document;
 
   var style_element = d.createElement('STYLE');
   var dom_events = 'addEventListener' in d;

public/app/core/utils/rangeutil.ts

@@ -92,7 +92,7 @@ function formatDate(date) {
 // now/d
 // if no to <expr> then to now is assumed
 export function describeTextRange(expr: any) {
-  let isLast = expr.indexOf('+') !== 0;
+  const isLast = expr.indexOf('+') !== 0;
   if (expr.indexOf('now') === -1) {
     expr = (isLast ? 'now-' : 'now') + expr;
   }
@@ -108,11 +108,11 @@ export function describeTextRange(expr: any) {
     opt = { from: 'now', to: expr };
   }
 
-  let parts = /^now([-+])(\d+)(\w)/.exec(expr);
+  const parts = /^now([-+])(\d+)(\w)/.exec(expr);
   if (parts) {
-    let unit = parts[3];
-    let amount = parseInt(parts[2]);
-    let span = spans[unit];
+    const unit = parts[3];
+    const amount = parseInt(parts[2]);
+    const span = spans[unit];
     if (span) {
       opt.display = isLast ? 'Last ' : 'Next ';
       opt.display += amount + ' ' + span.display;

public/app/core/utils/sort_by_keys.ts

@@ -7,7 +7,7 @@ export default function sortByKeys(input) {
 
   if (_.isPlainObject(input)) {
     var sortedObject = {};
-    for (let key of _.keys(input).sort()) {
+    for (const key of _.keys(input).sort()) {
       sortedObject[key] = sortByKeys(input[key]);
     }
     return sortedObject;

public/app/core/utils/tags.ts

@@ -67,9 +67,9 @@ const TAG_BORDER_COLORS = [
  * @param name tag name
  */
 export function getTagColorsFromName(name: string): { color: string; borderColor: string } {
-  let hash = djb2(name.toLowerCase());
-  let color = TAG_COLORS[Math.abs(hash % TAG_COLORS.length)];
-  let borderColor = TAG_BORDER_COLORS[Math.abs(hash % TAG_BORDER_COLORS.length)];
+  const hash = djb2(name.toLowerCase());
+  const color = TAG_COLORS[Math.abs(hash % TAG_COLORS.length)];
+  const borderColor = TAG_BORDER_COLORS[Math.abs(hash % TAG_BORDER_COLORS.length)];
   return { color, borderColor };
 }
 

public/app/core/utils/ticks.ts

@@ -7,7 +7,7 @@
  * @param count Ticks count
  */
 export function tickStep(start: number, stop: number, count: number): number {
-  let e10 = Math.sqrt(50),
+  const e10 = Math.sqrt(50),
     e5 = Math.sqrt(10),
     e2 = Math.sqrt(2);
 
@@ -76,7 +76,7 @@ export function getFlotRange(panelMin, panelMax, datamin, datamax) {
 
   let min = +(panelMin != null ? panelMin : datamin);
   let max = +(panelMax != null ? panelMax : datamax);
-  let delta = max - min;
+  const delta = max - min;
 
   if (delta === 0.0) {
     // Grafana fix: wide Y min and max using increased wideFactor
@@ -123,11 +123,11 @@ export function getFlotTickDecimals(datamin, datamax, axis, height) {
   const { min, max } = getFlotRange(axis.min, axis.max, datamin, datamax);
   const noTicks = 0.3 * Math.sqrt(height);
   const delta = (max - min) / noTicks;
-  let dec = -Math.floor(Math.log(delta) / Math.LN10);
+  const dec = -Math.floor(Math.log(delta) / Math.LN10);
 
-  let magn = Math.pow(10, -dec);
+  const magn = Math.pow(10, -dec);
   // norm is between 1.0 and 10.0
-  let norm = delta / magn;
+  const norm = delta / magn;
   let size;
 
   if (norm < 1.5) {
@@ -159,10 +159,10 @@ export function getFlotTickDecimals(datamin, datamax, axis, height) {
  */
 export function grafanaTimeFormat(ticks, min, max) {
   if (min && max && ticks) {
-    let range = max - min;
-    let secPerTick = range / ticks / 1000;
-    let oneDay = 86400000;
-    let oneYear = 31536000000;
+    const range = max - min;
+    const secPerTick = range / ticks / 1000;
+    const oneDay = 86400000;
+    const oneYear = 31536000000;
 
     if (secPerTick <= 45) {
       return '%H:%M:%S';
@@ -193,7 +193,7 @@ export function logp(value, base) {
  * Get decimal precision of number (3.14 => 2)
  */
 export function getPrecision(num: number): number {
-  let str = num.toString();
+  const str = num.toString();
   return getStringPrecision(str);
 }
 
@@ -201,7 +201,7 @@ export function getPrecision(num: number): number {
  * Get decimal precision of number stored as a string ("3.14" => 2)
  */
 export function getStringPrecision(num: string): number {
-  let dot_index = num.indexOf('.');
+  const dot_index = num.indexOf('.');
   if (dot_index === -1) {
     return 0;
   } else {

public/app/core/utils/url.ts

@@ -3,14 +3,14 @@
  */
 
 export function toUrlParams(a) {
-  let s = [];
-  let rbracket = /\[\]$/;
+  const s = [];
+  const rbracket = /\[\]$/;
 
-  let isArray = function(obj) {
+  const isArray = function(obj) {
     return Object.prototype.toString.call(obj) === '[object Array]';
   };
 
-  let add = function(k, v) {
+  const add = function(k, v) {
     v = typeof v === 'function' ? v() : v === null ? '' : v === undefined ? '' : v;
     if (typeof v !== 'boolean') {
       s[s.length] = encodeURIComponent(k) + '=' + encodeURIComponent(v);
@@ -19,7 +19,7 @@ export function toUrlParams(a) {
     }
   };
 
-  let buildParams = function(prefix, obj) {
+  const buildParams = function(prefix, obj) {
     var i, len, key;
 
     if (prefix) {

public/app/core/utils/version.ts

@@ -9,7 +9,7 @@ export class SemVersion {
   meta: string;
 
   constructor(version: string) {
-    let match = versionPattern.exec(version);
+    const match = versionPattern.exec(version);
     if (match) {
       this.major = Number(match[1]);
       this.minor = Number(match[2] || 0);
@@ -19,7 +19,7 @@ export class SemVersion {
   }
 
   isGtOrEq(version: string): boolean {
-    let compared = new SemVersion(version);
+    const compared = new SemVersion(version);
     return !(this.major < compared.major || this.minor < compared.minor || this.patch < compared.patch);
   }
 
@@ -29,6 +29,6 @@ export class SemVersion {
 }
 
 export function isVersionGtOrEq(a: string, b: string): boolean {
-  let a_semver = new SemVersion(a);
+  const a_semver = new SemVersion(a);
   return a_semver.isGtOrEq(b);
 }

public/app/features/alerting/alert_tab_ctrl.ts

@@ -184,7 +184,7 @@ export class AlertTabCtrl {
 
     ThresholdMapper.alertToGraphThresholds(this.panel);
 
-    for (let addedNotification of alert.notifications) {
+    for (const addedNotification of alert.notifications) {
       var model = _.find(this.notifications, { id: addedNotification.id });
       if (model && model.isDefault === false) {
         model.iconClass = this.getNotificationIcon(model.type);
@@ -192,7 +192,7 @@ export class AlertTabCtrl {
       }
     }
 
-    for (let notification of this.notifications) {
+    for (const notification of this.notifications) {
       if (notification.isDefault) {
         notification.iconClass = this.getNotificationIcon(notification.type);
         notification.bgColor = '#00678b';

public/app/features/alerting/notification_edit_ctrl.ts

@@ -30,7 +30,7 @@ export class AlertNotificationEditCtrl {
         this.notifiers = notifiers;
 
         // add option templates
-        for (let notifier of this.notifiers) {
+        for (const notifier of this.notifiers) {
           this.$templateCache.put(this.getNotifierTemplateId(notifier.type), notifier.optionsTemplate);
         }
 

public/app/features/alerting/threshold_mapper.ts

@@ -1,7 +1,7 @@
 export class ThresholdMapper {
   static alertToGraphThresholds(panel) {
     for (var i = 0; i < panel.alert.conditions.length; i++) {
-      let condition = panel.alert.conditions[i];
+      const condition = panel.alert.conditions[i];
       if (condition.type !== 'query') {
         continue;
       }
@@ -11,18 +11,18 @@ export class ThresholdMapper {
 
       switch (evaluator.type) {
         case 'gt': {
-          let value = evaluator.params[0];
+          const value = evaluator.params[0];
           thresholds.push({ value: value, op: 'gt' });
           break;
         }
         case 'lt': {
-          let value = evaluator.params[0];
+          const value = evaluator.params[0];
           thresholds.push({ value: value, op: 'lt' });
           break;
         }
         case 'outside_range': {
-          let value1 = evaluator.params[0];
-          let value2 = evaluator.params[1];
+          const value1 = evaluator.params[0];
+          const value2 = evaluator.params[1];
 
           if (value1 > value2) {
             thresholds.push({ value: value1, op: 'gt' });
@@ -35,8 +35,8 @@ export class ThresholdMapper {
           break;
         }
         case 'within_range': {
-          let value1 = evaluator.params[0];
-          let value2 = evaluator.params[1];
+          const value1 = evaluator.params[0];
+          const value2 = evaluator.params[1];
 
           if (value1 > value2) {
             thresholds.push({ value: value1, op: 'lt' });

public/app/features/annotations/annotations_srv.ts

@@ -91,7 +91,7 @@ export class AnnotationsSrv {
     var range = this.timeSrv.timeRange();
     var promises = [];
 
-    for (let annotation of dashboard.annotations.list) {
+    for (const annotation of dashboard.annotations.list) {
       if (!annotation.enable) {
         continue;
       }

public/app/features/annotations/event_editor.ts

@@ -31,7 +31,7 @@ export class EventEditorCtrl {
       return;
     }
 
-    let saveModel = _.cloneDeep(this.event);
+    const saveModel = _.cloneDeep(this.event);
     saveModel.time = saveModel.time.valueOf();
     saveModel.timeEnd = 0;
 
@@ -85,7 +85,7 @@ export class EventEditorCtrl {
 
 function tryEpochToMoment(timestamp) {
   if (timestamp && _.isNumber(timestamp)) {
-    let epoch = Number(timestamp);
+    const epoch = Number(timestamp);
     return moment(epoch);
   } else {
     return timestamp;

public/app/features/annotations/event_manager.ts

@@ -125,11 +125,11 @@ export class EventManager {
       }
     }
 
-    let regions = getRegions(annotations);
+    const regions = getRegions(annotations);
     addRegionMarking(regions, flotOptions);
 
-    let eventSectionHeight = 20;
-    let eventSectionMargin = 7;
+    const eventSectionHeight = 20;
+    const eventSectionMargin = 7;
     flotOptions.grid.eventSectionHeight = eventSectionMargin;
     flotOptions.xaxis.eventSectionHeight = eventSectionHeight;
 
@@ -147,8 +147,8 @@ function getRegions(events) {
 }
 
 function addRegionMarking(regions, flotOptions) {
-  let markings = flotOptions.grid.markings;
-  let defaultColor = DEFAULT_ANNOTATION_COLOR;
+  const markings = flotOptions.grid.markings;
+  const defaultColor = DEFAULT_ANNOTATION_COLOR;
   let fillColor;
 
   _.each(regions, region => {
@@ -167,7 +167,7 @@ function addRegionMarking(regions, flotOptions) {
 }
 
 function addAlphaToRGB(colorString: string, alpha: number): string {
-  let color = tinycolor(colorString);
+  const color = tinycolor(colorString);
   if (color.isValid()) {
     color.setAlpha(alpha);
     return color.toRgbString();

public/app/features/annotations/events_processing.ts

@@ -7,20 +7,20 @@ import _ from 'lodash';
  * @param options
  */
 export function makeRegions(annotations, options) {
-  let [regionEvents, singleEvents] = _.partition(annotations, 'regionId');
-  let regions = getRegions(regionEvents, options.range);
+  const [regionEvents, singleEvents] = _.partition(annotations, 'regionId');
+  const regions = getRegions(regionEvents, options.range);
   annotations = _.concat(regions, singleEvents);
   return annotations;
 }
 
 function getRegions(events, range) {
-  let region_events = _.filter(events, event => {
+  const region_events = _.filter(events, event => {
     return event.regionId;
   });
   let regions = _.groupBy(region_events, 'regionId');
   regions = _.compact(
     _.map(regions, region_events => {
-      let region_obj = _.head(region_events);
+      const region_obj = _.head(region_events);
       if (region_events && region_events.length > 1) {
         region_obj.timeEnd = region_events[1].time;
         region_obj.isRegion = true;
@@ -57,9 +57,9 @@ export function dedupAnnotations(annotations) {
   let dedup = [];
 
   // Split events by annotationId property existence
-  let events = _.partition(annotations, 'id');
+  const events = _.partition(annotations, 'id');
 
-  let eventsById = _.groupBy(events[0], 'id');
+  const eventsById = _.groupBy(events[0], 'id');
   dedup = _.map(eventsById, eventGroup => {
     if (eventGroup.length > 1 && !_.every(eventGroup, isPanelAlert)) {
       // Get first non-panel alert

public/app/features/annotations/specs/annotations_srv.test.ts

@@ -3,7 +3,7 @@ import 'app/features/dashboard/time_srv';
 import { AnnotationsSrv } from '../annotations_srv';
 
 describe('AnnotationsSrv', function() {
-  let $rootScope = {
+  const $rootScope = {
     onAppEvent: jest.fn(),
   };
   let $q;
@@ -11,7 +11,7 @@ describe('AnnotationsSrv', function() {
   let backendSrv;
   let timeSrv;
 
-  let annotationsSrv = new AnnotationsSrv($rootScope, $q, datasourceSrv, backendSrv, timeSrv);
+  const annotationsSrv = new AnnotationsSrv($rootScope, $q, datasourceSrv, backendSrv, timeSrv);
 
   describe('When translating the query result', () => {
     const annotationSource = {

public/app/features/annotations/specs/annotations_srv_specs.test.ts

@@ -24,7 +24,7 @@ describe('Annotations', () => {
         { id: 2, time: 2 },
       ];
 
-      let regions = makeRegions(testAnnotations, { range: range });
+      const regions = makeRegions(testAnnotations, { range: range });
       expect(regions).toEqual(expectedAnnotations);
     });
 
@@ -33,7 +33,7 @@ describe('Annotations', () => {
       testAnnotations = [{ id: 5, time: 4, regionId: 5 }];
       const expectedAnnotations = [{ id: 5, regionId: 5, isRegion: true, time: 4, timeEnd: 7 }];
 
-      let regions = makeRegions(testAnnotations, { range: range });
+      const regions = makeRegions(testAnnotations, { range: range });
       expect(regions).toEqual(expectedAnnotations);
     });
   });
@@ -49,7 +49,7 @@ describe('Annotations', () => {
       ];
       const expectedAnnotations = [{ id: 1, time: 1 }, { id: 2, time: 2 }, { id: 5, time: 5 }];
 
-      let deduplicated = dedupAnnotations(testAnnotations);
+      const deduplicated = dedupAnnotations(testAnnotations);
       expect(deduplicated).toEqual(expectedAnnotations);
     });
 
@@ -63,7 +63,7 @@ describe('Annotations', () => {
       ];
       const expectedAnnotations = [{ id: 1, time: 1 }, { id: 2, time: 2 }, { id: 5, time: 5 }];
 
-      let deduplicated = dedupAnnotations(testAnnotations);
+      const deduplicated = dedupAnnotations(testAnnotations);
       expect(deduplicated).toEqual(expectedAnnotations);
     });
   });

public/app/features/dashboard/ad_hoc_filters.ts

@@ -30,7 +30,7 @@ export class AdHocFiltersCtrl {
     if (this.variable.value && !_.isArray(this.variable.value)) {
     }
 
-    for (let tag of this.variable.filters) {
+    for (const tag of this.variable.filters) {
       if (this.segments.length > 0) {
         this.segments.push(this.uiSegmentSrv.newCondition('AND'));
       }

public/app/features/dashboard/change_tracker.ts

@@ -94,13 +94,13 @@ export class ChangeTracker {
   // remove stuff that should not count in diff
   cleanDashboardFromIgnoredChanges(dashData) {
     // need to new up the domain model class to get access to expand / collapse row logic
-    let model = new DashboardModel(dashData);
+    const model = new DashboardModel(dashData);
 
     // Expand all rows before making comparison. This is required because row expand / collapse
     // change order of panel array and panel positions.
     model.expandRows();
 
-    let dash = model.getSaveModelClone();
+    const dash = model.getSaveModelClone();
 
     // ignore time and refresh
     dash.time = 0;
@@ -138,8 +138,8 @@ export class ChangeTracker {
   }
 
   hasChanges() {
-    let current = this.cleanDashboardFromIgnoredChanges(this.current.getSaveModelClone());
-    let original = this.cleanDashboardFromIgnoredChanges(this.original);
+    const current = this.cleanDashboardFromIgnoredChanges(this.current.getSaveModelClone());
+    const original = this.cleanDashboardFromIgnoredChanges(this.original);
 
     var currentTimepicker = _.find(current.nav, { type: 'timepicker' });
     var originalTimepicker = _.find(original.nav, { type: 'timepicker' });

public/app/features/dashboard/dashboard_import_ctrl.ts

@@ -51,7 +51,7 @@ export class DashboardImportCtrl {
     this.inputs = [];
 
     if (this.dash.__inputs) {
-      for (let input of this.dash.__inputs) {
+      for (const input of this.dash.__inputs) {
         var inputModel = {
           name: input.name,
           label: input.label,
@@ -95,7 +95,7 @@ export class DashboardImportCtrl {
 
   inputValueChanged() {
     this.inputsValid = true;
-    for (let input of this.inputs) {
+    for (const input of this.inputs) {
       if (!input.value) {
         this.inputsValid = false;
       }

public/app/features/dashboard/dashboard_migration.ts

@@ -389,7 +389,7 @@ export class DashboardMigrator {
 
   upgradeToGridLayout(old) {
     let yPos = 0;
-    let widthFactor = GRID_COLUMN_COUNT / 12;
+    const widthFactor = GRID_COLUMN_COUNT / 12;
 
     const maxPanelId = _.max(
       _.flattenDeep(
@@ -407,15 +407,15 @@ export class DashboardMigrator {
     // Add special "row" panels if even one row is collapsed, repeated or has visible title
     const showRows = _.some(old.rows, row => row.collapse || row.showTitle || row.repeat);
 
-    for (let row of old.rows) {
+    for (const row of old.rows) {
       if (row.repeatIteration) {
         continue;
       }
 
-      let height: any = row.height || DEFAULT_ROW_HEIGHT;
+      const height: any = row.height || DEFAULT_ROW_HEIGHT;
       const rowGridHeight = getGridHeight(height);
 
-      let rowPanel: any = {};
+      const rowPanel: any = {};
       let rowPanelModel: PanelModel;
       if (showRows) {
         // add special row panel
@@ -436,9 +436,9 @@ export class DashboardMigrator {
         yPos++;
       }
 
-      let rowArea = new RowArea(rowGridHeight, GRID_COLUMN_COUNT, yPos);
+      const rowArea = new RowArea(rowGridHeight, GRID_COLUMN_COUNT, yPos);
 
-      for (let panel of row.panels) {
+      for (const panel of row.panels) {
         panel.span = panel.span || DEFAULT_PANEL_SPAN;
         if (panel.minSpan) {
           panel.minSpan = Math.min(GRID_COLUMN_COUNT, GRID_COLUMN_COUNT / 12 * panel.minSpan);
@@ -446,7 +446,7 @@ export class DashboardMigrator {
         const panelWidth = Math.floor(panel.span) * widthFactor;
         const panelHeight = panel.height ? getGridHeight(panel.height) : rowGridHeight;
 
-        let panelPos = rowArea.getPanelPosition(panelHeight, panelWidth);
+        const panelPos = rowArea.getPanelPosition(panelHeight, panelWidth);
         yPos = rowArea.yPos;
         panel.gridPos = {
           x: panelPos.x,

public/app/features/dashboard/dashboard_model.ts

@@ -95,7 +95,7 @@ export class DashboardModel {
 
   addBuiltInAnnotationQuery() {
     let found = false;
-    for (let item of this.annotations.list) {
+    for (const item of this.annotations.list) {
       if (item.builtIn === 1) {
         found = true;
         break;
@@ -138,7 +138,7 @@ export class DashboardModel {
 
   // cleans meta data and other non persistent state
   getSaveModelClone(options?) {
-    let defaults = _.defaults(options || {}, {
+    const defaults = _.defaults(options || {}, {
       saveVariables: true,
       saveTimerange: true,
     });
@@ -160,8 +160,8 @@ export class DashboardModel {
 
     if (!defaults.saveVariables) {
       for (let i = 0; i < copy.templating.list.length; i++) {
-        let current = copy.templating.list[i];
-        let original = _.find(this.originalTemplating, { name: current.name, type: current.type });
+        const current = copy.templating.list[i];
+        const original = _.find(this.originalTemplating, { name: current.name, type: current.type });
 
         if (!original) {
           continue;
@@ -213,13 +213,13 @@ export class DashboardModel {
   getNextPanelId() {
     let max = 0;
 
-    for (let panel of this.panels) {
+    for (const panel of this.panels) {
       if (panel.id > max) {
         max = panel.id;
       }
 
       if (panel.collapsed) {
-        for (let rowPanel of panel.panels) {
+        for (const rowPanel of panel.panels) {
           if (rowPanel.id > max) {
             max = rowPanel.id;
           }
@@ -237,7 +237,7 @@ export class DashboardModel {
   }
 
   getPanelById(id) {
-    for (let panel of this.panels) {
+    for (const panel of this.panels) {
       if (panel.id === id) {
         return panel;
       }
@@ -248,7 +248,7 @@ export class DashboardModel {
   addPanel(panelData) {
     panelData.id = this.getNextPanelId();
 
-    let panel = new PanelModel(panelData);
+    const panel = new PanelModel(panelData);
 
     this.panels.unshift(panel);
 
@@ -273,15 +273,15 @@ export class DashboardModel {
     }
 
     this.iteration = (this.iteration || new Date().getTime()) + 1;
-    let panelsToRemove = [];
+    const panelsToRemove = [];
 
     // cleanup scopedVars
-    for (let panel of this.panels) {
+    for (const panel of this.panels) {
       delete panel.scopedVars;
     }
 
     for (let i = 0; i < this.panels.length; i++) {
-      let panel = this.panels[i];
+      const panel = this.panels[i];
       if ((!panel.repeat || panel.repeatedByRow) && panel.repeatPanelId && panel.repeatIteration !== this.iteration) {
         panelsToRemove.push(panel);
       }
@@ -304,7 +304,7 @@ export class DashboardModel {
     this.iteration = (this.iteration || new Date().getTime()) + 1;
 
     for (let i = 0; i < this.panels.length; i++) {
-      let panel = this.panels[i];
+      const panel = this.panels[i];
       if (panel.repeat) {
         this.repeatPanel(panel, i);
       }
@@ -315,9 +315,9 @@ export class DashboardModel {
   }
 
   cleanUpRowRepeats(rowPanels) {
-    let panelsToRemove = [];
+    const panelsToRemove = [];
     for (let i = 0; i < rowPanels.length; i++) {
-      let panel = rowPanels[i];
+      const panel = rowPanels[i];
       if (!panel.repeat && panel.repeatPanelId) {
         panelsToRemove.push(panel);
       }
@@ -333,16 +333,16 @@ export class DashboardModel {
 
     let rowPanels = row.panels;
     if (!row.collapsed) {
-      let rowPanelIndex = _.findIndex(this.panels, p => p.id === row.id);
+      const rowPanelIndex = _.findIndex(this.panels, p => p.id === row.id);
       rowPanels = this.getRowPanels(rowPanelIndex);
     }
 
     this.cleanUpRowRepeats(rowPanels);
 
     for (let i = 0; i < rowPanels.length; i++) {
-      let panel = rowPanels[i];
+      const panel = rowPanels[i];
       if (panel.repeat) {
-        let panelIndex = _.findIndex(this.panels, p => p.id === panel.id);
+        const panelIndex = _.findIndex(this.panels, p => p.id === panel.id);
         this.repeatPanel(panel, panelIndex);
       }
     }
@@ -354,7 +354,7 @@ export class DashboardModel {
       return sourcePanel;
     }
 
-    let clone = new PanelModel(sourcePanel.getSaveModel());
+    const clone = new PanelModel(sourcePanel.getSaveModel());
     clone.id = this.getNextPanelId();
 
     // insert after source panel + value index
@@ -370,13 +370,13 @@ export class DashboardModel {
     // if first clone return source
     if (valueIndex === 0) {
       if (!sourceRowPanel.collapsed) {
-        let rowPanels = this.getRowPanels(sourcePanelIndex);
+        const rowPanels = this.getRowPanels(sourcePanelIndex);
         sourceRowPanel.panels = rowPanels;
       }
       return sourceRowPanel;
     }
 
-    let clone = new PanelModel(sourceRowPanel.getSaveModel());
+    const clone = new PanelModel(sourceRowPanel.getSaveModel());
     // for row clones we need to figure out panels under row to clone and where to insert clone
     let rowPanels, insertPos;
     if (sourceRowPanel.collapsed) {
@@ -397,7 +397,7 @@ export class DashboardModel {
   }
 
   repeatPanel(panel: PanelModel, panelIndex: number) {
-    let variable = _.find(this.templating.list, { name: panel.repeat });
+    const variable = _.find(this.templating.list, { name: panel.repeat });
     if (!variable) {
       return;
     }
@@ -407,13 +407,13 @@ export class DashboardModel {
       return;
     }
 
-    let selectedOptions = this.getSelectedVariableOptions(variable);
-    let minWidth = panel.minSpan || 6;
+    const selectedOptions = this.getSelectedVariableOptions(variable);
+    const minWidth = panel.minSpan || 6;
     let xPos = 0;
     let yPos = panel.gridPos.y;
 
     for (let index = 0; index < selectedOptions.length; index++) {
-      let option = selectedOptions[index];
+      const option = selectedOptions[index];
       let copy;
 
       copy = this.getPanelRepeatClone(panel, index, panelIndex);
@@ -443,9 +443,9 @@ export class DashboardModel {
     }
 
     // Update gridPos for panels below
-    let yOffset = yPos - panel.gridPos.y;
+    const yOffset = yPos - panel.gridPos.y;
     if (yOffset > 0) {
-      let panelBelowIndex = panelIndex + selectedOptions.length;
+      const panelBelowIndex = panelIndex + selectedOptions.length;
       for (let i = panelBelowIndex; i < this.panels.length; i++) {
         this.panels[i].gridPos.y += yOffset;
       }
@@ -453,7 +453,7 @@ export class DashboardModel {
   }
 
   repeatRow(panel: PanelModel, panelIndex: number, variable) {
-    let selectedOptions = this.getSelectedVariableOptions(variable);
+    const selectedOptions = this.getSelectedVariableOptions(variable);
     let yPos = panel.gridPos.y;
 
     function setScopedVars(panel, variableOption) {
@@ -462,12 +462,12 @@ export class DashboardModel {
     }
 
     for (let optionIndex = 0; optionIndex < selectedOptions.length; optionIndex++) {
-      let option = selectedOptions[optionIndex];
-      let rowCopy = this.getRowRepeatClone(panel, optionIndex, panelIndex);
+      const option = selectedOptions[optionIndex];
+      const rowCopy = this.getRowRepeatClone(panel, optionIndex, panelIndex);
       setScopedVars(rowCopy, option);
 
-      let rowHeight = this.getRowHeight(rowCopy);
-      let rowPanels = rowCopy.panels || [];
+      const rowHeight = this.getRowHeight(rowCopy);
+      const rowPanels = rowCopy.panels || [];
       let panelBelowIndex;
 
       if (panel.collapsed) {
@@ -483,11 +483,11 @@ export class DashboardModel {
         panelBelowIndex = panelIndex + optionIndex + 1;
       } else {
         // insert after 'row' panel
-        let insertPos = panelIndex + (rowPanels.length + 1) * optionIndex + 1;
+        const insertPos = panelIndex + (rowPanels.length + 1) * optionIndex + 1;
         _.each(rowPanels, (rowPanel, i) => {
           setScopedVars(rowPanel, option);
           if (optionIndex > 0) {
-            let cloneRowPanel = new PanelModel(rowPanel);
+            const cloneRowPanel = new PanelModel(rowPanel);
             this.updateRepeatedPanelIds(cloneRowPanel, true);
             // For exposed row additionally set proper Y grid position and add it to dashboard panels
             cloneRowPanel.gridPos.y += rowHeight * optionIndex;
@@ -650,29 +650,29 @@ export class DashboardModel {
   formatDate(date, format?) {
     date = moment.isMoment(date) ? date : moment(date);
     format = format || 'YYYY-MM-DD HH:mm:ss';
-    let timezone = this.getTimezone();
+    const timezone = this.getTimezone();
 
     return timezone === 'browser' ? moment(date).format(format) : moment.utc(date).format(format);
   }
 
   destroy() {
     this.events.removeAllListeners();
-    for (let panel of this.panels) {
+    for (const panel of this.panels) {
       panel.destroy();
     }
   }
 
   toggleRow(row: PanelModel) {
-    let rowIndex = _.indexOf(this.panels, row);
+    const rowIndex = _.indexOf(this.panels, row);
 
     if (row.collapsed) {
       row.collapsed = false;
-      let hasRepeat = _.some(row.panels, p => p.repeat);
+      const hasRepeat = _.some(row.panels, p => p.repeat);
 
       if (row.panels.length > 0) {
         // Use first panel to figure out if it was moved or pushed
-        let firstPanel = row.panels[0];
-        let yDiff = firstPanel.gridPos.y - (row.gridPos.y + row.gridPos.h);
+        const firstPanel = row.panels[0];
+        const yDiff = firstPanel.gridPos.y - (row.gridPos.y + row.gridPos.h);
 
         // start inserting after row
         let insertPos = rowIndex + 1;
@@ -680,7 +680,7 @@ export class DashboardModel {
         // needed to know home much panels below should be pushed down
         let yMax = row.gridPos.y;
 
-        for (let panel of row.panels) {
+        for (const panel of row.panels) {
           // make sure y is adjusted (in case row moved while collapsed)
           // console.log('yDiff', yDiff);
           panel.gridPos.y -= yDiff;
@@ -713,7 +713,7 @@ export class DashboardModel {
       return;
     }
 
-    let rowPanels = this.getRowPanels(rowIndex);
+    const rowPanels = this.getRowPanels(rowIndex);
 
     // remove panels
     _.pull(this.panels, ...rowPanels);
@@ -729,10 +729,10 @@ export class DashboardModel {
    * Will return all panels after rowIndex until it encounters another row
    */
   getRowPanels(rowIndex: number): PanelModel[] {
-    let rowPanels = [];
+    const rowPanels = [];
 
     for (let index = rowIndex + 1; index < this.panels.length; index++) {
-      let panel = this.panels[index];
+      const panel = this.panels[index];
 
       // break when encountering another row
       if (panel.type === 'row') {
@@ -791,7 +791,7 @@ export class DashboardModel {
   }
 
   private updateSchema(old) {
-    let migrator = new DashboardMigrator(this);
+    const migrator = new DashboardMigrator(this);
     migrator.updateSchema(old);
   }
 

public/app/features/dashboard/dashgrid/AddPanelPanel.tsx

@@ -68,18 +68,18 @@ export class AddPanelPanel extends React.Component<AddPanelPanelProps, AddPanelP
   }
 
   getCopiedPanelPlugins(filter) {
-    let panels = _.chain(config.panels)
+    const panels = _.chain(config.panels)
       .filter({ hideFromList: false })
       .map(item => item)
       .value();
     let copiedPanels = [];
 
-    let copiedPanelJson = store.get(LS_PANEL_COPY_KEY);
+    const copiedPanelJson = store.get(LS_PANEL_COPY_KEY);
     if (copiedPanelJson) {
-      let copiedPanel = JSON.parse(copiedPanelJson);
-      let pluginInfo = _.find(panels, { id: copiedPanel.type });
+      const copiedPanel = JSON.parse(copiedPanelJson);
+      const pluginInfo = _.find(panels, { id: copiedPanel.type });
       if (pluginInfo) {
-        let pluginCopy = _.cloneDeep(pluginInfo);
+        const pluginCopy = _.cloneDeep(pluginInfo);
         pluginCopy.name = copiedPanel.title;
         pluginCopy.sort = -1;
         pluginCopy.defaults = copiedPanel;
@@ -129,7 +129,7 @@ export class AddPanelPanel extends React.Component<AddPanelPanelProps, AddPanelP
   }
 
   renderText(text: string) {
-    let searchWords = this.state.filter.split('');
+    const searchWords = this.state.filter.split('');
     return <Highlighter highlightClassName="highlight-search-match" textToHighlight={text} searchWords={searchWords} />;
   }
 
@@ -156,7 +156,7 @@ export class AddPanelPanel extends React.Component<AddPanelPanelProps, AddPanelP
 
   filterKeyPress(evt) {
     if (evt.key === 'Enter') {
-      let panel = _.head(this.state.panelPlugins);
+      const panel = _.head(this.state.panelPlugins);
       if (panel) {
         this.onAddPanel(panel);
       }
@@ -164,7 +164,7 @@ export class AddPanelPanel extends React.Component<AddPanelPanelProps, AddPanelP
   }
 
   filterPanels(panels, filter) {
-    let regex = new RegExp(filter, 'i');
+    const regex = new RegExp(filter, 'i');
     return panels.filter(panel => {
       return regex.test(panel.name);
     });
@@ -189,12 +189,12 @@ export class AddPanelPanel extends React.Component<AddPanelPanelProps, AddPanelP
   }
 
   render() {
-    let addClass = classNames({
+    const addClass = classNames({
       'active active--panel': this.state.tab === 'Add',
       '': this.state.tab === 'Copy',
     });
 
-    let copyClass = classNames({
+    const copyClass = classNames({
       '': this.state.tab === 'Add',
       'active active--panel': this.state.tab === 'Copy',
     });

public/app/features/dashboard/dashgrid/DashboardGrid.tsx

@@ -94,8 +94,8 @@ export class DashboardGrid extends React.Component<DashboardGridProps, any> {
     const layout = [];
     this.panelMap = {};
 
-    for (let panel of this.dashboard.panels) {
-      let stringId = panel.id.toString();
+    for (const panel of this.dashboard.panels) {
+      const stringId = panel.id.toString();
       this.panelMap[stringId] = panel;
 
       if (!panel.gridPos) {
@@ -103,7 +103,7 @@ export class DashboardGrid extends React.Component<DashboardGridProps, any> {
         continue;
       }
 
-      let panelPos: any = {
+      const panelPos: any = {
         i: stringId,
         x: panel.gridPos.x,
         y: panel.gridPos.y,
@@ -174,7 +174,7 @@ export class DashboardGrid extends React.Component<DashboardGridProps, any> {
   renderPanels() {
     const panelElements = [];
 
-    for (let panel of this.dashboard.panels) {
+    for (const panel of this.dashboard.panels) {
       const panelClasses = classNames({ panel: true, 'panel--fullscreen': panel.fullscreen });
       panelElements.push(
         <div key={panel.id.toString()} className={panelClasses}>

public/app/features/dashboard/dashnav/dashnav.ts

@@ -22,7 +22,7 @@ export class DashNavCtrl {
   }
 
   toggleSettings() {
-    let search = this.$location.search();
+    const search = this.$location.search();
     if (search.editview) {
       delete search.editview;
     } else {
@@ -32,7 +32,7 @@ export class DashNavCtrl {
   }
 
   close() {
-    let search = this.$location.search();
+    const search = this.$location.search();
     if (search.editview) {
       delete search.editview;
     } else if (search.fullscreen) {

public/app/features/dashboard/export/export_modal.ts

@@ -29,7 +29,7 @@ export class DashExportCtrl {
 
   saveJson() {
     var clone = this.dash;
-    let editScope = this.$rootScope.$new();
+    const editScope = this.$rootScope.$new();
     editScope.object = clone;
     editScope.enableCopy = true;
 

public/app/features/dashboard/export/exporter.ts

@@ -24,7 +24,7 @@ export class DashboardExporter {
     var promises = [];
     var variableLookup: any = {};
 
-    for (let variable of saveModel.templating.list) {
+    for (const variable of saveModel.templating.list) {
       variableLookup[variable.name] = variable;
     }
 
@@ -69,7 +69,7 @@ export class DashboardExporter {
       }
 
       if (panel.targets) {
-        for (let target of panel.targets) {
+        for (const target of panel.targets) {
           if (target.datasource !== undefined) {
             templateizeDatasourceUsage(target);
           }
@@ -88,19 +88,19 @@ export class DashboardExporter {
     };
 
     // check up panel data sources
-    for (let panel of saveModel.panels) {
+    for (const panel of saveModel.panels) {
       processPanel(panel);
 
       // handle collapsed rows
       if (panel.collapsed !== undefined && panel.collapsed === true && panel.panels) {
-        for (let rowPanel of panel.panels) {
+        for (const rowPanel of panel.panels) {
           processPanel(rowPanel);
         }
       }
     }
 
     // templatize template vars
-    for (let variable of saveModel.templating.list) {
+    for (const variable of saveModel.templating.list) {
       if (variable.type === 'query') {
         templateizeDatasourceUsage(variable);
         variable.options = [];
@@ -110,7 +110,7 @@ export class DashboardExporter {
     }
 
     // templatize annotations vars
-    for (let annotationDef of saveModel.annotations.list) {
+    for (const annotationDef of saveModel.annotations.list) {
       templateizeDatasourceUsage(annotationDef);
     }
 
@@ -129,7 +129,7 @@ export class DashboardExporter {
         });
 
         // templatize constants
-        for (let variable of saveModel.templating.list) {
+        for (const variable of saveModel.templating.list) {
           if (variable.type === 'constant') {
             var refName = 'VAR_' + variable.name.replace(' ', '_').toUpperCase();
             inputs.push({

public/app/features/dashboard/history/history.ts

@@ -67,7 +67,7 @@ export class HistoryListCtrl {
   }
 
   revisionSelectionChanged() {
-    let selected = _.filter(this.revisions, { checked: true }).length;
+    const selected = _.filter(this.revisions, { checked: true }).length;
     this.canCompare = selected === 2;
   }
 
@@ -134,7 +134,7 @@ export class HistoryListCtrl {
       .getHistoryList(this.dashboard, options)
       .then(revisions => {
         // set formatted dates & default values
-        for (let rev of revisions) {
+        for (const rev of revisions) {
           rev.createdDateString = this.formatDate(rev.created);
           rev.ageString = this.formatBasicDate(rev.created);
           rev.checked = false;

public/app/features/dashboard/settings/settings.ts

@@ -109,7 +109,7 @@ export class SettingsCtrl {
     const params = this.$location.search();
     const url = this.$location.path();
 
-    for (let section of this.sections) {
+    for (const section of this.sections) {
       const sectionParams = _.defaults({ editview: section.id }, params);
       section.url = config.appSubUrl + url + '?' + $.param(sectionParams);
     }

public/app/features/dashboard/shareModalCtrl.ts

@@ -91,7 +91,7 @@ export function ShareModalCtrl($scope, $rootScope, $location, $timeout, timeSrv,
   // This function will try to return the proper full name of the local timezone
   // Chrome does not handle the timezone offset (but phantomjs does)
   $scope.getLocalTimeZone = function() {
-    let utcOffset = '&tz=UTC' + encodeURIComponent(moment().format('Z'));
+    const utcOffset = '&tz=UTC' + encodeURIComponent(moment().format('Z'));
 
     // Older browser does not the internationalization API
     if (!(<any>window).Intl) {

public/app/features/dashboard/specs/dashboard_migration.test.ts

@@ -151,18 +151,18 @@ describe('DashboardModel', function() {
 
     it('should create proper grid', function() {
       model.rows = [createRow({ collapse: false, height: 8 }, [[6], [6]])];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [{ x: 0, y: 0, w: 12, h: 8 }, { x: 12, y: 0, w: 12, h: 8 }];
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [{ x: 0, y: 0, w: 12, h: 8 }, { x: 12, y: 0, w: 12, h: 8 }];
 
       expect(panelGridPos).toEqual(expectedGrid);
     });
 
     it('should add special "row" panel if row is collapsed', function() {
       model.rows = [createRow({ collapse: true, height: 8 }, [[6], [6]]), createRow({ height: 8 }, [[12]])];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [
         { x: 0, y: 0, w: 24, h: 8 }, // row
         { x: 0, y: 1, w: 24, h: 8 }, // row
         { x: 0, y: 2, w: 24, h: 8 },
@@ -176,9 +176,9 @@ describe('DashboardModel', function() {
         createRow({ showTitle: true, title: 'Row', height: 8 }, [[6], [6]]),
         createRow({ height: 8 }, [[12]]),
       ];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [
         { x: 0, y: 0, w: 24, h: 8 }, // row
         { x: 0, y: 1, w: 12, h: 8 },
         { x: 12, y: 1, w: 12, h: 8 },
@@ -196,9 +196,9 @@ describe('DashboardModel', function() {
         createRow({ height: 8 }, [[12], [6], [6]]),
         createRow({ collapse: true, height: 8 }, [[12]]),
       ];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [
         { x: 0, y: 0, w: 24, h: 8 }, // row
         { x: 0, y: 1, w: 24, h: 8 }, // row
         { x: 0, y: 2, w: 24, h: 8 },
@@ -214,9 +214,9 @@ describe('DashboardModel', function() {
 
     it('should add all rows if even one collapsed or titled row is present', function() {
       model.rows = [createRow({ collapse: true, height: 8 }, [[6], [6]]), createRow({ height: 8 }, [[12]])];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [
         { x: 0, y: 0, w: 24, h: 8 }, // row
         { x: 0, y: 1, w: 24, h: 8 }, // row
         { x: 0, y: 2, w: 24, h: 8 },
@@ -230,9 +230,9 @@ describe('DashboardModel', function() {
         createRow({ height: 6 }, [[6], [6, 3], [6, 3]]),
         createRow({ height: 6 }, [[4], [4], [4, 3], [4, 3]]),
       ];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [
         { x: 0, y: 0, w: 12, h: 6 },
         { x: 12, y: 0, w: 12, h: 3 },
         { x: 12, y: 3, w: 12, h: 3 },
@@ -247,9 +247,9 @@ describe('DashboardModel', function() {
 
     it('should place panel to the right side of panel having bigger height', function() {
       model.rows = [createRow({ height: 6 }, [[4], [2, 3], [4, 6], [2, 3], [2, 3]])];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [
         { x: 0, y: 0, w: 8, h: 6 },
         { x: 8, y: 0, w: 4, h: 3 },
         { x: 12, y: 0, w: 8, h: 6 },
@@ -262,9 +262,9 @@ describe('DashboardModel', function() {
 
     it('should fill current row if it possible', function() {
       model.rows = [createRow({ height: 9 }, [[4], [2, 3], [4, 6], [2, 3], [2, 3], [8, 3]])];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [
         { x: 0, y: 0, w: 8, h: 9 },
         { x: 8, y: 0, w: 4, h: 3 },
         { x: 12, y: 0, w: 8, h: 6 },
@@ -278,9 +278,9 @@ describe('DashboardModel', function() {
 
     it('should fill current row if it possible (2)', function() {
       model.rows = [createRow({ height: 8 }, [[4], [2, 3], [4, 6], [2, 3], [2, 3], [8, 3]])];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [
         { x: 0, y: 0, w: 8, h: 8 },
         { x: 8, y: 0, w: 4, h: 3 },
         { x: 12, y: 0, w: 8, h: 6 },
@@ -294,9 +294,9 @@ describe('DashboardModel', function() {
 
     it('should fill current row if panel height more than row height', function() {
       model.rows = [createRow({ height: 6 }, [[4], [2, 3], [4, 8], [2, 3], [2, 3]])];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [
         { x: 0, y: 0, w: 8, h: 6 },
         { x: 8, y: 0, w: 4, h: 3 },
         { x: 12, y: 0, w: 8, h: 8 },
@@ -309,9 +309,9 @@ describe('DashboardModel', function() {
 
     it('should wrap panels to multiple rows', function() {
       model.rows = [createRow({ height: 6 }, [[6], [6], [12], [6], [3], [3]])];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [
         { x: 0, y: 0, w: 12, h: 6 },
         { x: 12, y: 0, w: 12, h: 6 },
         { x: 0, y: 6, w: 24, h: 6 },
@@ -328,9 +328,9 @@ describe('DashboardModel', function() {
         createRow({ showTitle: true, title: 'Row', height: 8, repeat: 'server' }, [[6]]),
         createRow({ height: 8 }, [[12]]),
       ];
-      let dashboard = new DashboardModel(model);
-      let panelGridPos = getGridPositions(dashboard);
-      let expectedGrid = [
+      const dashboard = new DashboardModel(model);
+      const panelGridPos = getGridPositions(dashboard);
+      const expectedGrid = [
         { x: 0, y: 0, w: 24, h: 8 },
         { x: 0, y: 1, w: 12, h: 8 },
         { x: 0, y: 9, w: 24, h: 8 },
@@ -359,7 +359,7 @@ describe('DashboardModel', function() {
         ),
       ];
 
-      let dashboard = new DashboardModel(model);
+      const dashboard = new DashboardModel(model);
       expect(dashboard.panels[0].repeat).toBe('server');
       expect(dashboard.panels.length).toBe(2);
     });
@@ -368,7 +368,7 @@ describe('DashboardModel', function() {
       model.rows = [createRow({ height: 8 }, [[6]])];
       model.rows[0].panels[0] = { minSpan: 12 };
 
-      let dashboard = new DashboardModel(model);
+      const dashboard = new DashboardModel(model);
       expect(dashboard.panels[0].minSpan).toBe(24);
     });
 
@@ -376,7 +376,7 @@ describe('DashboardModel', function() {
       model.rows = [createRow({ collapse: true, height: 8 }, [[6], [6]])];
       model.rows[0].panels[0] = {};
 
-      let dashboard = new DashboardModel(model);
+      const dashboard = new DashboardModel(model);
       expect(dashboard.panels[0].id).toBe(1);
     });
   });
@@ -386,15 +386,15 @@ function createRow(options, panelDescriptions: any[]) {
   const PANEL_HEIGHT_STEP = GRID_CELL_HEIGHT + GRID_CELL_VMARGIN;
   let { collapse, height, showTitle, title, repeat, repeatIteration } = options;
   height = height * PANEL_HEIGHT_STEP;
-  let panels = [];
+  const panels = [];
   _.each(panelDescriptions, panelDesc => {
-    let panel = { span: panelDesc[0] };
+    const panel = { span: panelDesc[0] };
     if (panelDesc.length > 1) {
       panel['height'] = panelDesc[1] * PANEL_HEIGHT_STEP;
     }
     panels.push(panel);
   });
-  let row = {
+  const row = {
     collapse,
     height,
     showTitle,

public/app/features/dashboard/specs/dashboard_model.test.ts

@@ -457,16 +457,16 @@ describe('DashboardModel', function() {
     });
 
     it('getSaveModelClone should return original time when saveTimerange=false', () => {
-      let options = { saveTimerange: false };
-      let saveModel = model.getSaveModelClone(options);
+      const options = { saveTimerange: false };
+      const saveModel = model.getSaveModelClone(options);
 
       expect(saveModel.time.from).toBe('now-6h');
       expect(saveModel.time.to).toBe('now');
     });
 
     it('getSaveModelClone should return updated time when saveTimerange=true', () => {
-      let options = { saveTimerange: true };
-      let saveModel = model.getSaveModelClone(options);
+      const options = { saveTimerange: true };
+      const saveModel = model.getSaveModelClone(options);
 
       expect(saveModel.time.from).toBe('now-3h');
       expect(saveModel.time.to).toBe('now-1h');
@@ -478,16 +478,16 @@ describe('DashboardModel', function() {
     });
 
     it('getSaveModelClone should return original time when saveTimerange=false', () => {
-      let options = { saveTimerange: false };
-      let saveModel = model.getSaveModelClone(options);
+      const options = { saveTimerange: false };
+      const saveModel = model.getSaveModelClone(options);
 
       expect(saveModel.time.from).toBe('now-6h');
       expect(saveModel.time.to).toBe('now');
     });
 
     it('getSaveModelClone should return updated time when saveTimerange=true', () => {
-      let options = { saveTimerange: true };
-      let saveModel = model.getSaveModelClone(options);
+      const options = { saveTimerange: true };
+      const saveModel = model.getSaveModelClone(options);
 
       expect(saveModel.time.from).toBe('now-3h');
       expect(saveModel.time.to).toBe('now-1h');
@@ -542,8 +542,8 @@ describe('DashboardModel', function() {
     it('getSaveModelClone should return original variable when saveVariables=false', () => {
       model.templating.list[0].current.text = 'server_002';
 
-      let options = { saveVariables: false };
-      let saveModel = model.getSaveModelClone(options);
+      const options = { saveVariables: false };
+      const saveModel = model.getSaveModelClone(options);
 
       expect(saveModel.templating.list[0].current.text).toBe('server_001');
     });
@@ -551,8 +551,8 @@ describe('DashboardModel', function() {
     it('getSaveModelClone should return updated variable when saveVariables=true', () => {
       model.templating.list[0].current.text = 'server_002';
 
-      let options = { saveVariables: true };
-      let saveModel = model.getSaveModelClone(options);
+      const options = { saveVariables: true };
+      const saveModel = model.getSaveModelClone(options);
 
       expect(saveModel.templating.list[0].current.text).toBe('server_002');
     });
@@ -620,8 +620,8 @@ describe('DashboardModel', function() {
     it('getSaveModelClone should return original variable when saveVariables=false', () => {
       model.templating.list[0].filters[0].value = 'server 1';
 
-      let options = { saveVariables: false };
-      let saveModel = model.getSaveModelClone(options);
+      const options = { saveVariables: false };
+      const saveModel = model.getSaveModelClone(options);
 
       expect(saveModel.templating.list[0].filters[0].value).toBe('server 20');
     });
@@ -629,8 +629,8 @@ describe('DashboardModel', function() {
     it('getSaveModelClone should return updated variable when saveVariables=true', () => {
       model.templating.list[0].filters[0].value = 'server 1';
 
-      let options = { saveVariables: true };
-      let saveModel = model.getSaveModelClone(options);
+      const options = { saveVariables: true };
+      const saveModel = model.getSaveModelClone(options);
 
       expect(saveModel.templating.list[0].filters[0].value).toBe('server 1');
     });

public/app/features/dashboard/specs/history_ctrl.test.ts

@@ -70,7 +70,7 @@ describe('HistoryListCtrl', () => {
       });
 
       it('should add a checked property to each revision', () => {
-        let actual = _.filter(historyListCtrl.revisions, rev => rev.hasOwnProperty('checked'));
+        const actual = _.filter(historyListCtrl.revisions, rev => rev.hasOwnProperty('checked'));
         expect(actual.length).toBe(4);
       });
 
@@ -78,7 +78,7 @@ describe('HistoryListCtrl', () => {
         historyListCtrl.revisions[0].checked = true;
         historyListCtrl.revisions[2].checked = true;
         historyListCtrl.reset();
-        let actual = _.filter(historyListCtrl.revisions, rev => !rev.checked);
+        const actual = _.filter(historyListCtrl.revisions, rev => !rev.checked);
         expect(actual.length).toBe(4);
       });
     });

public/app/features/dashboard/specs/history_srv.test.ts

@@ -8,7 +8,7 @@ describe('historySrv', function() {
   const versionsResponse = versions();
   const restoreResponse = restore;
 
-  let backendSrv = {
+  const backendSrv = {
     get: jest.fn(() => Promise.resolve({})),
     post: jest.fn(() => Promise.resolve({})),
   };
@@ -44,7 +44,7 @@ describe('historySrv', function() {
 
   describe('restoreDashboard', () => {
     it('should return a success response given valid parameters', function() {
-      let version = 6;
+      const version = 6;
       backendSrv.post = jest.fn(() => Promise.resolve(restoreResponse(version)));
       historySrv = new HistorySrv(backendSrv);
       return historySrv.restoreDashboard(dash, version).then(function(response) {
@@ -54,7 +54,7 @@ describe('historySrv', function() {
 
     it('should return an empty object when not given an id', async () => {
       historySrv = new HistorySrv(backendSrv);
-      let rsp = await historySrv.restoreDashboard(emptyDash, 6);
+      const rsp = await historySrv.restoreDashboard(emptyDash, 6);
       expect(rsp).toEqual({});
     });
   });

public/app/features/dashboard/specs/repeat.test.ts

@@ -8,7 +8,7 @@ describe('given dashboard with panel repeat', function() {
   var dashboard;
 
   beforeEach(function() {
-    let dashboardJSON = {
+    const dashboardJSON = {
       panels: [
         { id: 1, type: 'row', gridPos: { x: 0, y: 0, h: 1, w: 24 } },
         { id: 2, repeat: 'apps', repeatDirection: 'h', gridPos: { x: 0, y: 1, h: 2, w: 8 } },

public/app/features/dashboard/specs/viewstate_srv.test.ts

@@ -4,12 +4,12 @@ import config from 'app/core/config';
 import { DashboardViewState } from '../view_state_srv';
 
 describe('when updating view state', () => {
-  let location = {
+  const location = {
     replace: jest.fn(),
     search: jest.fn(),
   };
 
-  let $scope = {
+  const $scope = {
     onAppEvent: jest.fn(() => {}),
     dashboard: {
       meta: {},
@@ -17,7 +17,7 @@ describe('when updating view state', () => {
     },
   };
 
-  let $rootScope = {};
+  const $rootScope = {};
   let viewState;
 
   beforeEach(() => {

public/app/features/dashboard/validation_srv.ts

@@ -37,7 +37,7 @@ export class ValidationSrv {
       });
     }
 
-    let deferred = this.$q.defer();
+    const deferred = this.$q.defer();
 
     const promises = [];
     promises.push(this.backendSrv.search({ type: hitTypes.FOLDER, folderIds: [folderId], query: name }));
@@ -54,7 +54,7 @@ export class ValidationSrv {
         hits = hits.concat(res[1]);
       }
 
-      for (let hit of hits) {
+      for (const hit of hits) {
         if (nameLowerCased === hit.title.toLowerCase()) {
           deferred.reject({
             type: 'EXISTING',

public/app/features/dashboard/view_state_srv.ts

@@ -111,9 +111,9 @@ export class DashboardViewState {
   }
 
   toggleCollapsedPanelRow(panelId) {
-    for (let panel of this.dashboard.panels) {
+    for (const panel of this.dashboard.panels) {
       if (panel.collapsed) {
-        for (let rowPanel of panel.panels) {
+        for (const rowPanel of panel.panels) {
           if (rowPanel.id === panelId) {
             this.dashboard.toggleRow(panel);
             return;

public/app/features/org/org_users_ctrl.ts

@@ -44,7 +44,7 @@ export class OrgUsersCtrl {
   }
 
   onQueryUpdated() {
-    let regex = new RegExp(this.searchQuery, 'ig');
+    const regex = new RegExp(this.searchQuery, 'ig');
     this.users = _.filter(this.unfiltered, item => {
       return regex.test(item.email) || regex.test(item.login);
     });

public/app/features/panel/metrics_tab.ts

@@ -28,7 +28,7 @@ export class MetricsTabCtrl {
     this.datasources = datasourceSrv.getMetricSources();
     this.panelDsValue = this.panelCtrl.panel.datasource;
 
-    for (let ds of this.datasources) {
+    for (const ds of this.datasources) {
       if (ds.value === this.panelDsValue) {
         this.datasourceInstance = ds;
       }

public/app/features/panel/panel_ctrl.ts

@@ -138,7 +138,7 @@ export class PanelCtrl {
   }
 
   getMenu() {
-    let menu = [];
+    const menu = [];
     menu.push({
       text: 'View',
       click: 'ctrl.viewPanel();',
@@ -166,7 +166,7 @@ export class PanelCtrl {
     // Additional items from sub-class
     menu.push(...this.getAdditionalMenuItems());
 
-    let extendedMenu = this.getExtendedMenu();
+    const extendedMenu = this.getExtendedMenu();
     menu.push({
       text: 'More ...',
       click: '',
@@ -189,7 +189,7 @@ export class PanelCtrl {
   }
 
   getExtendedMenu() {
-    let menu = [];
+    const menu = [];
     if (!this.fullscreen && this.dashboard.meta.canEdit) {
       menu.push({
         text: 'Duplicate',
@@ -259,7 +259,7 @@ export class PanelCtrl {
   }
 
   editPanelJson() {
-    let editScope = this.$scope.$root.$new();
+    const editScope = this.$scope.$root.$new();
     editScope.object = this.panel.getSaveModel();
     editScope.updateHandler = this.replacePanel.bind(this);
     editScope.enableCopy = true;
@@ -276,12 +276,12 @@ export class PanelCtrl {
   }
 
   replacePanel(newPanel, oldPanel) {
-    let dashboard = this.dashboard;
-    let index = _.findIndex(dashboard.panels, panel => {
+    const dashboard = this.dashboard;
+    const index = _.findIndex(dashboard.panels, panel => {
       return panel.id === oldPanel.id;
     });
 
-    let deletedPanel = dashboard.panels.splice(index, 1);
+    const deletedPanel = dashboard.panels.splice(index, 1);
     this.dashboard.events.emit('panel-removed', deletedPanel);
 
     newPanel = new PanelModel(newPanel);
@@ -333,7 +333,7 @@ export class PanelCtrl {
 
     if (this.panel.links && this.panel.links.length > 0) {
       html += '<ul>';
-      for (let link of this.panel.links) {
+      for (const link of this.panel.links) {
         var info = linkSrv.getPanelLinkAnchorInfo(link, this.panel.scopedVars);
         html +=
           '<li><a class="panel-menu-link" href="' +

public/app/features/panel/panel_directive.ts

@@ -112,8 +112,8 @@ module.directive('grafanaPanel', function($rootScope, $document, $timeout) {
             </div>
           `;
 
-          let scrollRoot = panelContent;
-          let scroller = panelContent.find(':first').find(':first');
+          const scrollRoot = panelContent;
+          const scroller = panelContent.find(':first').find(':first');
 
           scrollRoot.addClass(scrollRootClass);
           $(scrollBarHTML).appendTo(scrollRoot);

public/app/features/panel/panel_header.ts

@@ -60,7 +60,7 @@ function renderMenuItem(item, ctrl) {
 
   if (item.submenu) {
     html += '<ul class="dropdown-menu dropdown-menu--menu panel-menu">';
-    for (let subitem of item.submenu) {
+    for (const subitem of item.submenu) {
       html += renderMenuItem(subitem, ctrl);
     }
     html += '</ul>';
@@ -73,7 +73,7 @@ function renderMenuItem(item, ctrl) {
 function createMenuTemplate(ctrl) {
   let html = '';
 
-  for (let item of ctrl.getMenu()) {
+  for (const item of ctrl.getMenu()) {
     html += renderMenuItem(item, ctrl);
   }
 
@@ -86,7 +86,7 @@ function panelHeader($compile) {
     restrict: 'E',
     template: template,
     link: function(scope, elem, attrs) {
-      let menuElem = elem.find('.panel-menu');
+      const menuElem = elem.find('.panel-menu');
       let menuScope;
       let isDragged;
 
@@ -99,7 +99,7 @@ function panelHeader($compile) {
         }
 
         menuScope = scope.$new();
-        let menuHtml = createMenuTemplate(scope.ctrl);
+        const menuHtml = createMenuTemplate(scope.ctrl);
         menuElem.html(menuHtml);
         $compile(menuElem)(menuScope);
 
@@ -132,12 +132,12 @@ function panelHeader($compile) {
           .find('[data-toggle=dropdown]')
           .parentsUntil('.panel')
           .parent();
-        let menuElem = elem.find('[data-toggle=dropdown]').parent();
+        const menuElem = elem.find('[data-toggle=dropdown]').parent();
         panelElem = panelElem && panelElem.length ? panelElem[0] : undefined;
         if (panelElem) {
           panelElem = $(panelElem);
           $(panelGridClass).removeClass(menuOpenClass);
-          let state = !menuElem.hasClass('open');
+          const state = !menuElem.hasClass('open');
           panelElem.toggleClass(menuOpenClass, state);
         }
       }

public/app/features/panel/solo_panel_ctrl.ts

@@ -34,7 +34,7 @@ export class SoloPanelCtrl {
     };
 
     $scope.initPanelScope = function() {
-      let panelInfo = $scope.dashboard.getPanelInfoById(panelId);
+      const panelInfo = $scope.dashboard.getPanelInfoById(panelId);
 
       // fake row ctrl scope
       $scope.ctrl = {

public/app/features/panellinks/specs/link_srv.test.ts

@@ -2,7 +2,7 @@ import { LinkSrv } from '../link_srv';
 import _ from 'lodash';
 
 jest.mock('angular', () => {
-  let AngularJSMock = require('test/mocks/angular');
+  const AngularJSMock = require('test/mocks/angular');
   return new AngularJSMock();
 });
 

public/app/features/playlist/playlist_routes.ts

@@ -24,7 +24,7 @@ function grafanaRoutes($routeProvider) {
       controller: 'PlaylistsCtrl',
       resolve: {
         init: function(playlistSrv, $route) {
-          let playlistId = $route.current.params.id;
+          const playlistId = $route.current.params.id;
           playlistSrv.start(playlistId);
         },
       },

public/app/features/playlist/specs/playlist_edit_ctrl.test.ts

@@ -4,7 +4,7 @@ import { PlaylistEditCtrl } from '../playlist_edit_ctrl';
 describe('PlaylistEditCtrl', () => {
   var ctx: any;
   beforeEach(() => {
-    let navModelSrv = {
+    const navModelSrv = {
       getNav: () => {
         return { breadcrumbs: [], node: {} };
       },

public/app/features/plugins/ds_list_ctrl.ts

@@ -17,7 +17,7 @@ export class DataSourcesCtrl {
   }
 
   onQueryUpdated() {
-    let regex = new RegExp(this.searchQuery, 'ig');
+    const regex = new RegExp(this.searchQuery, 'ig');
     this.datasources = _.filter(this.unfiltered, item => {
       regex.lastIndex = 0;
       return regex.test(item.name) || regex.test(item.type);

public/app/features/plugins/plugin_component.ts

@@ -68,7 +68,7 @@ function pluginDirectiveLoader($compile, datasourceSrv, $rootScope, $q, $http, $
       },
     };
 
-    let panelInfo = config.panels[scope.panel.type];
+    const panelInfo = config.panels[scope.panel.type];
     var panelCtrlPromise = Promise.resolve(UnknownPanelCtrl);
     if (panelInfo) {
       panelCtrlPromise = importPluginModule(panelInfo.module).then(function(panelModule) {
@@ -107,7 +107,7 @@ function pluginDirectiveLoader($compile, datasourceSrv, $rootScope, $q, $http, $
     switch (attrs.type) {
       // QueryCtrl
       case 'query-ctrl': {
-        let datasource = scope.target.datasource || scope.ctrl.panel.datasource;
+        const datasource = scope.target.datasource || scope.ctrl.panel.datasource;
         return datasourceSrv.get(datasource).then(ds => {
           scope.datasource = ds;
 
@@ -160,7 +160,7 @@ function pluginDirectiveLoader($compile, datasourceSrv, $rootScope, $q, $http, $
       }
       // AppConfigCtrl
       case 'app-config-ctrl': {
-        let model = scope.ctrl.model;
+        const model = scope.ctrl.model;
         return importPluginModule(model.module).then(function(appModule) {
           return {
             baseUrl: model.baseUrl,
@@ -173,7 +173,7 @@ function pluginDirectiveLoader($compile, datasourceSrv, $rootScope, $q, $http, $
       }
       // App Page
       case 'app-page': {
-        let appModel = scope.ctrl.appModel;
+        const appModel = scope.ctrl.appModel;
         return importPluginModule(appModel.module).then(function(appModule) {
           return {
             baseUrl: appModel.baseUrl,

public/app/features/plugins/plugin_edit_ctrl.ts

@@ -53,7 +53,7 @@ export class PluginEditCtrl {
         url: `plugins/${this.model.id}/edit?tab=config`,
       });
 
-      let hasDashboards = _.find(model.includes, { type: 'dashboard' });
+      const hasDashboards = _.find(model.includes, { type: 'dashboard' });
 
       if (hasDashboards) {
         this.navModel.main.children.push({
@@ -69,7 +69,7 @@ export class PluginEditCtrl {
 
     this.tab = this.$routeParams.tab || defaultTab;
 
-    for (let tab of this.navModel.main.children) {
+    for (const tab of this.navModel.main.children) {
       if (tab.id === this.tab) {
         tab.active = true;
       }
@@ -98,7 +98,7 @@ export class PluginEditCtrl {
   initReadme() {
     return this.backendSrv.get(`/api/plugins/${this.pluginId}/markdown/readme`).then(res => {
       var md = new Remarkable({
-        linkify: true
+        linkify: true,
       });
       this.readmeHtml = this.$sce.trustAsHtml(md.render(res));
     });

public/app/features/plugins/plugin_list_ctrl.ts

@@ -20,7 +20,7 @@ export class PluginListCtrl {
   }
 
   onQueryUpdated() {
-    let regex = new RegExp(this.searchQuery, 'ig');
+    const regex = new RegExp(this.searchQuery, 'ig');
     this.plugins = _.filter(this.allPlugins, item => {
       return regex.test(item.name) || regex.test(item.type);
     });

public/app/features/plugins/plugin_loader.ts

@@ -140,12 +140,12 @@ const flotDeps = [
   'jquery.flot.events',
   'jquery.flot.gauge',
 ];
-for (let flotDep of flotDeps) {
+for (const flotDep of flotDeps) {
   exposeToPlugin(flotDep, { fakeDep: 1 });
 }
 
 export function importPluginModule(path: string): Promise<any> {
-  let builtIn = builtInPlugins[path];
+  const builtIn = builtInPlugins[path];
   if (builtIn) {
     return Promise.resolve(builtIn);
   }

public/app/features/plugins/plugin_page_ctrl.ts

@@ -33,7 +33,7 @@ export class AppPageCtrl {
       return;
     }
 
-    let pluginNav = this.navModelSrv.getNav('plugin-page-' + app.id);
+    const pluginNav = this.navModelSrv.getNav('plugin-page-' + app.id);
 
     this.navModel = {
       main: {

public/app/features/plugins/specs/datasource_srv.test.ts

@@ -16,7 +16,7 @@ const templateSrv = {
 };
 
 describe('datasource_srv', function() {
-  let _datasourceSrv = new DatasourceSrv({}, {}, {}, templateSrv);
+  const _datasourceSrv = new DatasourceSrv({}, {}, {}, templateSrv);
 
   describe('when loading explore sources', () => {
     beforeEach(() => {
@@ -46,7 +46,7 @@ describe('datasource_srv', function() {
 
   describe('when loading metric sources', () => {
     let metricSources;
-    let unsortedDatasources = {
+    const unsortedDatasources = {
       mmm: {
         type: 'test-db',
         meta: { metrics: { m: 1 } },

public/app/features/templating/specs/editor_ctrl.test.ts

@@ -9,7 +9,7 @@ jest.mock('app/core/app_events', () => {
 });
 
 describe('VariableEditorCtrl', () => {
-  let scope = {
+  const scope = {
     runQuery: () => {
       return Promise.resolve({});
     },

public/app/features/templating/specs/variable_srv_init.test.ts

@@ -5,7 +5,7 @@ import { VariableSrv } from '../variable_srv';
 import $q from 'q';
 
 describe('VariableSrv init', function() {
-  let templateSrv = {
+  const templateSrv = {
     init: vars => {
       this.variables = vars;
     },
@@ -17,8 +17,8 @@ describe('VariableSrv init', function() {
       }),
   };
 
-  let $injector = <any>{};
-  let $rootscope = {
+  const $injector = <any>{};
+  const $rootscope = {
     $on: () => {},
   };
 

public/app/features/templating/variable_srv.ts

@@ -23,7 +23,7 @@ export class VariableSrv {
     this.templateSrv.init(this.variables);
 
     // init variables
-    for (let variable of this.variables) {
+    for (const variable of this.variables) {
       variable.initLock = this.$q.defer();
     }
 
@@ -60,7 +60,7 @@ export class VariableSrv {
   processVariable(variable, queryParams) {
     var dependencies = [];
 
-    for (let otherVariable of this.variables) {
+    for (const otherVariable of this.variables) {
       if (variable.dependsOn(otherVariable)) {
         dependencies.push(otherVariable.initLock.promise);
       }
@@ -212,13 +212,13 @@ export class VariableSrv {
       });
 
       let defaultText = urlValue;
-      let defaultValue = urlValue;
+      const defaultValue = urlValue;
 
       if (!option && _.isArray(urlValue)) {
         defaultText = [];
 
         for (let n = 0; n < urlValue.length; n++) {
-          let t = _.find(variable.options, op => {
+          const t = _.find(variable.options, op => {
             return op.value === urlValue[n];
           });
 
@@ -275,7 +275,7 @@ export class VariableSrv {
       this.addVariable(variable);
     }
 
-    let filters = variable.filters;
+    const filters = variable.filters;
     let filter = _.find(filters, { key: options.key, value: options.value });
 
     if (!filter) {
@@ -288,7 +288,7 @@ export class VariableSrv {
   }
 
   createGraph() {
-    let g = new Graph();
+    const g = new Graph();
 
     this.variables.forEach(v1 => {
       g.createNode(v1.name);

public/app/plugins/datasource/cloudwatch/datasource.ts

@@ -45,7 +45,7 @@ export default class CloudWatchDatasource {
       item.returnData = typeof item.hide === 'undefined' ? true : !item.hide;
 
       // valid ExtendedStatistics is like p90.00, check the pattern
-      let hasInvalidStatistics = item.statistics.some(s => {
+      const hasInvalidStatistics = item.statistics.some(s => {
         return s.indexOf('p') === 0 && !/p\d{2}\.\d{2}/.test(s);
       });
       if (hasInvalidStatistics) {
@@ -402,7 +402,7 @@ export default class CloudWatchDatasource {
             value: v,
           };
         });
-    let useSelectedVariables =
+    const useSelectedVariables =
       selectedVariables.some(s => {
         return s.value === currentVariables[0].value;
       }) || currentVariables[0].value === '$__all';