diff --git a/lib/plugins/browsertime/analyzer.js b/lib/plugins/browsertime/analyzer.js
index 90bbd971b..92cf5c9af 100644
--- a/lib/plugins/browsertime/analyzer.js
+++ b/lib/plugins/browsertime/analyzer.js
@@ -51,9 +51,9 @@ function addExtraScripts(scriptsByCategory, pluginScripts) {
 }
 
 function setupAsynScripts(asyncScripts) {
-  var allAsyncScripts = {};
+  const allAsyncScripts = {};
   // For all different script in the array
-  for (var scripts of asyncScripts) {
+  for (let scripts of asyncScripts) {
     // and then for all scripts in that category
     forEach(scripts.scripts, function(script, name) {
       set(allAsyncScripts, scripts.category + '.' + name, script);
diff --git a/lib/plugins/budget/verify.js b/lib/plugins/budget/verify.js
index 0d6886e1b..4b91122c5 100644
--- a/lib/plugins/budget/verify.js
+++ b/lib/plugins/budget/verify.js
@@ -35,7 +35,7 @@ module.exports = {
     const working = [];
     // do we have an entry in the budget for this kind of message?
     if (budgets[message.type]) {
-      for (var budget of budgets[message.type]) {
+      for (let budget of budgets[message.type]) {
         let value = get(message.data, budget.metric);
 
         if (value !== undefined) {
diff --git a/lib/plugins/html/setup/detailed.js b/lib/plugins/html/setup/detailed.js
index 7332f3d80..5aba588a8 100644
--- a/lib/plugins/html/setup/detailed.js
+++ b/lib/plugins/html/setup/detailed.js
@@ -143,7 +143,7 @@ module.exports = function(data) {
     }
 
     if (summary.custom) {
-      for (var key of Object.keys(summary.custom)) {
+      for (let key of Object.keys(summary.custom)) {
         rows.push(row(summary.custom[key], key));
       }
     }
diff --git a/lib/plugins/html/setup/summaryBoxes.js b/lib/plugins/html/setup/summaryBoxes.js
index 95db0ca8c..dadd6dfcb 100644
--- a/lib/plugins/html/setup/summaryBoxes.js
+++ b/lib/plugins/html/setup/summaryBoxes.js
@@ -257,7 +257,7 @@ module.exports = function(data) {
     }
 
     if (summary.custom) {
-      for (var key of Object.keys(summary.custom)) {
+      for (let key of Object.keys(summary.custom)) {
         boxes.push(infoBox(summary.custom[key], key));
       }
     }
diff --git a/lib/plugins/html/templates/index.pug b/lib/plugins/html/templates/index.pug
index 7330fe1bc..431a82e25 100644
--- a/lib/plugins/html/templates/index.pug
+++ b/lib/plugins/html/templates/index.pug
@@ -18,7 +18,7 @@ block content
     each rows in boxes
       .row
         each box in rows
-          - var length = rows.length
+          - const length = rows.length
           case length
             when 3
               .one-third.column
diff --git a/lib/plugins/html/templates/runInfo.pug b/lib/plugins/html/templates/runInfo.pug
index 0120a3eb7..eb23df0fd 100644
--- a/lib/plugins/html/templates/runInfo.pug
+++ b/lib/plugins/html/templates/runInfo.pug
@@ -1,5 +1,5 @@
 
-- var profile = options.mobile ? 'mobile' : 'desktop'
+- const profile = options.mobile ? 'mobile' : 'desktop'
   h2.url #{h.plural(noPages,'page')} analyzed for #{h.short(context.name, 30)}
   p.small Tested #{timestamp} using #{h.cap(options.browsertime.browser)} for
     | #{ h.get(options, 'browsertime.chrome.android.package') ?  h.get(options, 'browsertime.chrome.android.package') + ' ': ''}
diff --git a/lib/plugins/html/templates/toplist.pug b/lib/plugins/html/templates/toplist.pug
index 710a9577d..d9db3731d 100644
--- a/lib/plugins/html/templates/toplist.pug
+++ b/lib/plugins/html/templates/toplist.pug
@@ -18,8 +18,8 @@ block content
   include runInfo
 
   if (assetsBySize)
-    - var topLists = ['javascript', 'image', 'css', 'html'];
-    - var contentTypeNames = {javascript: 'JavaScript', image: 'image' , css: 'CSS', html : 'HTML'}
+    - const topLists = ['javascript', 'image', 'css', 'html'];
+    - const contentTypeNames = {javascript: 'JavaScript', image: 'image' , css: 'CSS', html : 'HTML'}
     ul
       li.group-item.active Quick links
       each type in topLists
diff --git a/lib/plugins/html/templates/url/coach/index.pug b/lib/plugins/html/templates/url/coach/index.pug
index aa5015c03..56e43372e 100644
--- a/lib/plugins/html/templates/url/coach/index.pug
+++ b/lib/plugins/html/templates/url/coach/index.pug
@@ -27,7 +27,7 @@ mixin adviceInfo(name, perfectScore, node)
   else
     p #{perfectScore}
 
-- var advice = pageInfo.data.coach.run ? pageInfo.data.coach.run.advice : pageInfo.data.coach.pageSummary.advice;
+- const advice = pageInfo.data.coach.run ? pageInfo.data.coach.run.advice : pageInfo.data.coach.pageSummary.advice;
 
 h2 Coach
 p.small
@@ -36,9 +36,9 @@ p.small
   
 script(type='text/javascript').
   function toggleRow(toggleElement) {
-    var rows = toggleElement.nextSibling.getElementsByClassName("u-hideable");
-    for (var i = 0; i < rows.length; ++i) {
-      var status = rows[i].currentStyle ? rows[i].currentStyle.display :
+    const rows = toggleElement.nextSibling.getElementsByClassName("u-hideable");
+    for (let i = 0; i < rows.length; ++i) {
+      const status = rows[i].currentStyle ? rows[i].currentStyle.display :
                               getComputedStyle(rows[i], null).display;
       rows[i].style.display = (status === 'none') ? "table-row" : "none";
     }
diff --git a/lib/plugins/html/templates/url/includes/pageRunInfo.pug b/lib/plugins/html/templates/url/includes/pageRunInfo.pug
index bf287c07c..587a1eb6d 100644
--- a/lib/plugins/html/templates/url/includes/pageRunInfo.pug
+++ b/lib/plugins/html/templates/url/includes/pageRunInfo.pug
@@ -1,5 +1,5 @@
-- var profile = options.mobile ? 'mobile' : 'desktop'
-- var runTime = h.get(pageInfo, 'pageInfo.data.browsertime.run.timestamp', timestamp)
+- const profile = options.mobile ? 'mobile' : 'desktop'
+- const runTime = h.get(pageInfo, 'pageInfo.data.browsertime.run.timestamp', timestamp)
 p.small Tested #{runTime} using #{h.cap(options.browsertime.browser)} #{browser.version} for
   | #{ h.get(options, 'browsertime.chrome.android.package') ?  ' ' + h.get(options, 'browsertime.chrome.android.package') + ' ': ''}
   | #{options.preURL ? 'preURL ' + h.short(options.preURL, 60) + ' ': ''}
diff --git a/lib/plugins/html/templates/url/iteration/downloads.pug b/lib/plugins/html/templates/url/iteration/downloads.pug
index ca9578930..e5a38b540 100644
--- a/lib/plugins/html/templates/url/iteration/downloads.pug
+++ b/lib/plugins/html/templates/url/iteration/downloads.pug
@@ -1,11 +1,11 @@
 if options.browsertime.video
-    - var videoPath = 'data/video/' + (iteration ? iteration : 1) +'.mp4'
+    - const videoPath = 'data/video/' + (iteration ? iteration : 1) +'.mp4'
     a.button.button-download(href=videoPath, download=downloadName + '-video.mp4') Download video
 if options.browsertime.chrome && options.browsertime.chrome.timeline
-    - var tracePath = 'data/trace-' + (iteration ? iteration : 1) + '.json.gz'
+    - const tracePath = 'data/trace-' + (iteration ? iteration : 1) + '.json.gz'
     a.button.button-download(href=tracePath, download=downloadName + '-timeline.json.gz') Download timeline
 if d.browsertime && d.browsertime.har    
-    - var harEnding = options.gzipHAR ? '.har.gz' : '.har'
-    - var harName = 'data/browsertime' + harEnding
-    - var harDownloadName = downloadName + harEnding
+    - const harEnding = options.gzipHAR ? '.har.gz' : '.har'
+    - const harName = 'data/browsertime' + harEnding
+    - const harDownloadName = downloadName + harEnding
     a.button.button-download(href=harName, download=harDownloadName) Download HAR    
diff --git a/lib/plugins/html/templates/url/iteration/index.pug b/lib/plugins/html/templates/url/iteration/index.pug
index 59608f0c0..64bd813fd 100644
--- a/lib/plugins/html/templates/url/iteration/index.pug
+++ b/lib/plugins/html/templates/url/iteration/index.pug
@@ -1,10 +1,10 @@
 extends ../../layout.pug
 
 block content
-  - var d = pageInfo.data
+  - const d = pageInfo.data
   - runNumber = iteration
-  - var daTitle = daurlAlias ? daurlAlias : daurl
-  - var downloadName = (daTitle + '-' + runNumber + '-' + options.browser + '-' + timestamp).replace(/(https?\:\/\/)|( )|(:)/ig, '')
+  - const daTitle = daurlAlias ? daurlAlias : daurl
+  - const downloadName = (daTitle + '-' + runNumber + '-' + options.browser + '-' + timestamp).replace(/(https?\:\/\/)|( )|(:)/ig, '')
 
   h1 Run #{runNumber} summary
   h5.url
@@ -104,7 +104,7 @@ block content
                  img.screenshot(src=screenshotName, alt='Screenshot')
              else if hasScreenShots
                - screenshotName = 'data/screenshots/' + iteration + '.' + screenShotType
-               - var width = options.mobile ? 150 : '100%';
+               - const width = options.mobile ? 150 : '100%';
                a(href=screenshotName)
                  img.screenshot(src=screenshotName, width=width, alt='Screenshot')
        .downloads
@@ -130,6 +130,6 @@ block content
         include ../pagexray/index.pug
 
     each pageRun in pageRuns
-      - var panelName = pageRun.id + '-panel'
+      - const panelName = pageRun.id + '-panel'
       section(id=panelName)
         p !{pugs[pageRun.id]}
diff --git a/lib/plugins/html/templates/url/metrics/index.pug b/lib/plugins/html/templates/url/metrics/index.pug
index 235ea56ae..f46ac68e7 100644
--- a/lib/plugins/html/templates/url/metrics/index.pug
+++ b/lib/plugins/html/templates/url/metrics/index.pug
@@ -1,8 +1,8 @@
-- var browsertime = medianRun ? pageInfo.data.browsertime.pageSummary.browserScripts[medianRun.runIndex - 1] : pageInfo.data.browsertime.run 
+- const browsertime = medianRun ? pageInfo.data.browsertime.pageSummary.browserScripts[medianRun.runIndex - 1] : pageInfo.data.browsertime.run 
 
 if  browsertime
-  - var timings = browsertime.timings;
-  - var visualMetrics = browsertime.visualMetrics;
+  - const timings = browsertime.timings;
+  - const visualMetrics = browsertime.visualMetrics;
   - baseHelpURL = rootPath + 'help.html#';
 
   if options.browsertime.visualMetrics && visualMetrics
@@ -131,7 +131,7 @@ if  browsertime
   .downloads
 
     if options.browsertime.chrome && options.browsertime.chrome.timeline
-      - var tracePath = 'data/trace-' + (runNumber? runNumber : 1) + '.json.gz'
+      - const tracePath = 'data/trace-' + (runNumber? runNumber : 1) + '.json.gz'
       a.button.button-download(href=tracePath, download=downloadName + '-timeline.json.gz') Download timeline
   if options.browsertime.visualElements
    a#visual-elements
diff --git a/lib/plugins/html/templates/url/metrics/visualProgress.pug b/lib/plugins/html/templates/url/metrics/visualProgress.pug
index 25aff463c..d63f60a66 100644
--- a/lib/plugins/html/templates/url/metrics/visualProgress.pug
+++ b/lib/plugins/html/templates/url/metrics/visualProgress.pug
@@ -1,11 +1,11 @@
-- var allRows = browsertime.visualMetrics.VisualProgress.split(',')
-- var seriesVisualProgress = [];
-- var oldPercent = -1;
-- var oldValue = -1;
+- const allRows = browsertime.visualMetrics.VisualProgress.split(',')
+- const seriesVisualProgress = [];
+- const oldPercent = -1;
+- const oldValue = -1;
 each eachRow in allRows
-  - var row = eachRow.split('=')
-  - var newValue = (Number(row[0])/1000).toFixed(1)
-  - var percent = row[1]
+  - const row = eachRow.split('=')
+  - const newValue = (Number(row[0])/1000).toFixed(1)
+  - const percent = row[1]
   //- Sometimes VisualMetrics report the same percentage multiple times after each other
   // and since the original time is in ms we wanna remove entries on the same 0.1 s
   if percent !== oldPercent &&  newValue !== oldValue
@@ -14,7 +14,7 @@ each eachRow in allRows
     - seriesVisualProgress.push({x: newValue, y: Number(percent.replace('%',''))})
 script(type='text/javascript').
   document.addEventListener("DOMContentLoaded", function() {
-      var visualProgressChart = new Chartist.Line('#ct-visualprogress', {
+      const visualProgressChart = new Chartist.Line('#ct-visualprogress', {
         series: [!{JSON.stringify(seriesVisualProgress)}],
         }, {
         showArea: true,
@@ -60,7 +60,7 @@ script(type='text/javascript').
             }),
             Chartist.plugins.tooltip({
               transformTooltipTextFnc: function(text) {
-                var m = text.split(',');
+                const m = text.split(',');
                 return m[0] + 's ' + m[1] + '%';
               }
             })
diff --git a/lib/plugins/html/templates/url/pagexray/index.pug b/lib/plugins/html/templates/url/pagexray/index.pug
index 6b4f7fc51..a58612c66 100644
--- a/lib/plugins/html/templates/url/pagexray/index.pug
+++ b/lib/plugins/html/templates/url/pagexray/index.pug
@@ -2,7 +2,7 @@ include ../../_tableMixins
 
 a
 h2 PageXray
-- var pagexray = pageInfo.data.pagexray.run || pageInfo.data.pagexray.pageSummary;
+- const pagexray = pageInfo.data.pagexray.run || pageInfo.data.pagexray.pageSummary;
 p.small Hard facts about the page.
 a#pagexray-summary
 .row
diff --git a/lib/plugins/html/templates/url/summary/downloads.pug b/lib/plugins/html/templates/url/summary/downloads.pug
index e371af172..63dc6d4e1 100644
--- a/lib/plugins/html/templates/url/summary/downloads.pug
+++ b/lib/plugins/html/templates/url/summary/downloads.pug
@@ -1,13 +1,13 @@
 if options.html.logDownloadLink
       a.button.button-download(href=rootPath + 'logs/sitespeed.io.log', download) Download run log
 if options.browsertime.video
-    - var videoPath = 'data/video/' + (runIndex ? (Number(runIndex)+1) : 1) +'.mp4'
+    - const videoPath = 'data/video/' + (runIndex ? (Number(runIndex)+1) : 1) +'.mp4'
     a.button.button-download(href=videoPath, download=downloadName + '-video.mp4') Download video
 if options.browsertime.chrome && options.browsertime.chrome.timeline
-    - var tracePath = 'data/trace-' + (runNumber? runNumber : 1) + '.json.gz'
+    - const tracePath = 'data/trace-' + (runNumber? runNumber : 1) + '.json.gz'
     a.button.button-download(href=tracePath, download=downloadName + '-timeline.json.gz') Download timeline
 if d.browsertime && d.browsertime.har    
-    - var harEnding = options.gzipHAR ? '.har.gz' : '.har'
-    - var harName = 'data/browsertime' + harEnding
-    - var harDownloadName = downloadName + harEnding
+    - const harEnding = options.gzipHAR ? '.har.gz' : '.har'
+    - const harName = 'data/browsertime' + harEnding
+    - const harDownloadName = downloadName + harEnding
     a.button.button-download(href=harName, download=harDownloadName) Download HAR    
diff --git a/lib/plugins/html/templates/url/summary/index.pug b/lib/plugins/html/templates/url/summary/index.pug
index 4494cc87c..676546b55 100644
--- a/lib/plugins/html/templates/url/summary/index.pug
+++ b/lib/plugins/html/templates/url/summary/index.pug
@@ -1,9 +1,9 @@
 extends ./layout.pug
 
 block content
-  - var d = pageInfo.data
-  - var daTitle = daurlAlias ? daurlAlias : daurl
-  - var downloadName = (daTitle + '-' + options.browser + '-' + timestamp).replace(/(https?\:\/\/)|( )|(:)/ig, '')
+  - const d = pageInfo.data
+  - const daTitle = daurlAlias ? daurlAlias : daurl
+  - const downloadName = (daTitle + '-' + options.browser + '-' + timestamp).replace(/(https?\:\/\/)|( )|(:)/ig, '')
   h1 Page summary
 
   h5.url
@@ -94,9 +94,9 @@ block content
 
         .one-half.column
             if hasScreenShots
-              - var width = options.mobile ? 150 : '100%';
-              - var screenshotNo = medianRun ? medianRun.runIndex : 1
-              - var screenshotName = 'data/screenshots/' + screenshotNo + '.' + screenShotType
+              - const width = options.mobile ? 150 : '100%';
+              - const screenshotNo = medianRun ? medianRun.runIndex : 1
+              - const screenshotName = 'data/screenshots/' + screenshotNo + '.' + screenShotType
               a(href=screenshotName)
                 img.screenshot(src=screenshotName, width=width, alt='Screenshot of run ' + screenshotNo)
             else if !d.browsertime && d.webpagetest
@@ -128,6 +128,6 @@ block content
         include ../pagexray/index.pug
 
     each pageSummary in pageSummaries
-      - var panelName = pageSummary.id + '-panel'
+      - const panelName = pageSummary.id + '-panel'
       section(id=panelName)
         p !{pugs[pageSummary.id]}
diff --git a/lib/plugins/html/templates/url/video/index.pug b/lib/plugins/html/templates/url/video/index.pug
index a4e287164..5a31673ae 100644
--- a/lib/plugins/html/templates/url/video/index.pug
+++ b/lib/plugins/html/templates/url/video/index.pug
@@ -1,5 +1,5 @@
-- var videoIndex = medianRun ? medianRun.runIndex : iteration;
-- var width = options.mobile ? 'max-width: 400px;' : h.get(options, 'browsertime.chrome.android.package') ? 'max-width: 400px;' : 'width: 100%'
+- const videoIndex = medianRun ? medianRun.runIndex : iteration;
+- const width = options.mobile ? 'max-width: 400px;' : h.get(options, 'browsertime.chrome.android.package') ? 'max-width: 400px;' : 'width: 100%'
 
 a#video
 h3 Video 
@@ -10,5 +10,5 @@ h3 Video
 
 script(src= rootPath + 'js/video.novtt.min.js')
 
-- var videoPath = 'data/video/' + (iteration ? iteration : medianRun.runIndex ) +'.mp4'
+- const videoPath = 'data/video/' + (iteration ? iteration : medianRun.runIndex ) +'.mp4'
 a.button.button-download(href=videoPath, download=downloadName + '-video.mp4') Download video
diff --git a/lib/plugins/html/templates/url/waterfall/fetchHAR.pug b/lib/plugins/html/templates/url/waterfall/fetchHAR.pug
index 9f6707a5a..3cff7baf7 100644
--- a/lib/plugins/html/templates/url/waterfall/fetchHAR.pug
+++ b/lib/plugins/html/templates/url/waterfall/fetchHAR.pug
@@ -2,10 +2,10 @@
 script(src= rootPath + 'js/fetch.min.js')
 script(src= rootPath + 'js/perf-cascade.min.js')
 script(type='text/javascript').
-  var outputHolderEl = document.getElementById("output");
-  var pageSelectorEl = document.getElementById("page-selector");
-  var legendHolderEl = document.getElementById("legend-holder");
-  var options = {
+  const outputHolderEl = document.getElementById("output");
+  const pageSelectorEl = document.getElementById("page-selector");
+  const legendHolderEl = document.getElementById("legend-holder");
+  const options = {
     rowHeight: 23,
     showAlignmentHelpers : false,
     showIndicatorIcons: false,
@@ -21,10 +21,10 @@ if options.gzipHAR
       if (window["fetch"]) {
           window["fetch"]('data/browsertime.har.gz')
           .then(f => f.arrayBuffer()).then(arrayBuffer => {
-            var byteArray = new Uint8Array(arrayBuffer);
-            var gunzip = new Zlib.Gunzip(byteArray);
-            var decompressedArray = gunzip.decompress();
-            var string = '';
+            const byteArray = new Uint8Array(arrayBuffer);
+            const gunzip = new Zlib.Gunzip(byteArray);
+            const decompressedArray = gunzip.decompress();
+            let string = '';
             // only way to make it work on Safari iOS?
             try {
               string = new TextDecoder("utf-8").decode(decompressedArray);
@@ -73,8 +73,8 @@ if options.gzipHAR
               }
               string = Utf8ArrayToStr(decompressedArray);
             }
-            var har = JSON.parse(string);
-            var perfCascadeSvg = perfCascade.fromHar(har, options);
+            const har = JSON.parse(string);
+            const perfCascadeSvg = perfCascade.fromHar(har, options);
             document.getElementById('output').classList.remove('loader');
             outputHolderEl.appendChild(perfCascadeSvg);
           })
@@ -84,7 +84,7 @@ else
       if (window["fetch"]) {
        window["fetch"]('data/browsertime.har')
        .then(f => f.json()).then(har => {
-         var perfCascadeSvg = perfCascade.fromHar(har, options);
+         const perfCascadeSvg = perfCascade.fromHar(har, options);
          document.getElementById('output').classList.remove('loader');
          outputHolderEl.appendChild(perfCascadeSvg);
        })
diff --git a/lib/plugins/html/templates/url/waterfall/includeHARinHTML.pug b/lib/plugins/html/templates/url/waterfall/includeHARinHTML.pug
index 0a73906eb..f4612a583 100644
--- a/lib/plugins/html/templates/url/waterfall/includeHARinHTML.pug
+++ b/lib/plugins/html/templates/url/waterfall/includeHARinHTML.pug
@@ -5,10 +5,10 @@
 
 script(src= rootPath + 'js/perf-cascade.min.js')
 script(type='text/javascript').
-  var outputHolderEl = document.getElementById("output");
-  var pageSelectorEl = document.getElementById("page-selector");
-  var legendHolderEl = document.getElementById("legend-holder");
-  var options = {
+  const outputHolderEl = document.getElementById("output");
+  const pageSelectorEl = document.getElementById("page-selector");
+  const legendHolderEl = document.getElementById("legend-holder");
+  const options = {
     rowHeight: 23,
     showAlignmentHelpers : false,
     showIndicatorIcons: false,
@@ -19,6 +19,6 @@ script(type='text/javascript').
     pageSelector: pageSelectorEl
 
   };
-  var har = !{JSON.stringify(dahar.log)};
-  var perfCascadeSvg =  perfCascade.fromHar(har, options);
+  const har = !{JSON.stringify(dahar.log)};
+  const perfCascadeSvg =  perfCascade.fromHar(har, options);
   outputHolderEl.appendChild(perfCascadeSvg);
diff --git a/lib/plugins/html/templates/url/waterfall/index.pug b/lib/plugins/html/templates/url/waterfall/index.pug
index 3950cac32..38d89dff0 100644
--- a/lib/plugins/html/templates/url/waterfall/index.pug
+++ b/lib/plugins/html/templates/url/waterfall/index.pug
@@ -21,7 +21,7 @@ else
   include ./includeHARinHTML.pug
 
 .downloads
-  - var harEnding = options.gzipHAR ? '.har.gz' : '.har'
-  - var harName = 'data/browsertime' + harEnding
-  - var harDownloadName = downloadName + harEnding
+  - const harEnding = options.gzipHAR ? '.har.gz' : '.har'
+  - const harName = 'data/browsertime' + harEnding
+  - const harDownloadName = downloadName + harEnding
   a.button.button-download(href=harName, download=harDownloadName) Download HAR
diff --git a/lib/plugins/influxdb/data-generator.js b/lib/plugins/influxdb/data-generator.js
index 3a522069d..4d2c6871b 100644
--- a/lib/plugins/influxdb/data-generator.js
+++ b/lib/plugins/influxdb/data-generator.js
@@ -10,7 +10,7 @@ class InfluxDBDataGenerator {
     this.includeQueryParams = !!includeQueryParams;
     this.options = options;
     this.defaultTags = {};
-    for (var row of options.influxdb.tags.split(',')) {
+    for (let row of options.influxdb.tags.split(',')) {
       const keyAndValue = row.split('=');
       this.defaultTags[keyAndValue[0]] = keyAndValue[1];
     }
diff --git a/lib/plugins/influxdb/send-annotation.js b/lib/plugins/influxdb/send-annotation.js
index 84ebce9a4..40e2cce00 100644
--- a/lib/plugins/influxdb/send-annotation.js
+++ b/lib/plugins/influxdb/send-annotation.js
@@ -37,7 +37,7 @@ module.exports = {
     const timestamp = Math.round(dayjs() / 1000);
     // if we have a category, let us send that category too
     if (options.influxdb.tags) {
-      for (var row of options.influxdb.tags.split(',')) {
+      for (let row of options.influxdb.tags.split(',')) {
         const keyAndValue = row.split('=');
         tags.push(keyAndValue[1]);
       }
diff --git a/lib/plugins/webpagetest/pug/index.pug b/lib/plugins/webpagetest/pug/index.pug
index 4a72b5522..d742824e0 100644
--- a/lib/plugins/webpagetest/pug/index.pug
+++ b/lib/plugins/webpagetest/pug/index.pug
@@ -10,9 +10,9 @@ mixin numberCell(title, number)
 mixin sizeCell(title, size)
   td.number(data-title=title, data-value= size)= h.size.format(size)
 
-- var wpt = pageInfo.data.webpagetest.run ? pageInfo.data.webpagetest.run : pageInfo.data.webpagetest.pageSummary.data.median
-- var wptRoot = pageInfo.data.webpagetest.run ? pageInfo.data.webpagetest : pageInfo.data.webpagetest.pageSummary.data;
-- var wptRun  = runNumber? runNumber : 1
+- const wpt = pageInfo.data.webpagetest.run ? pageInfo.data.webpagetest.run : pageInfo.data.webpagetest.pageSummary.data.median
+- const wptRoot = pageInfo.data.webpagetest.run ? pageInfo.data.webpagetest : pageInfo.data.webpagetest.pageSummary.data;
+- const wptRun  = runNumber? runNumber : 1
 
 a
 h2 WebPageTest
@@ -73,20 +73,20 @@ p.small Metrics and data collected using #{options.webpagetest.host}.&nbsp;
     img.u-max-full-width(src='data/screenshots/wpt-' + wptRun  + '-firstView.png', alt='Screenshot')
 
 .downloads
-  - var harEnding = options.gzipHAR ? '.har.gz' : '.har'
-  - var harName = 'data/webpagetest' + harEnding
-  - var harDownloadName = downloadName + '-webpagetest-' + harEnding
+  - const harEnding = options.gzipHAR ? '.har.gz' : '.har'
+  - const harName = 'data/webpagetest' + harEnding
+  - const harDownloadName = downloadName + '-webpagetest-' + harEnding
 
   a.button.button-download(href=harName, download=downloadName) Download HAR
   if options.webpagetest.timeline
-    - var tracePath = 'data/trace-' + wptRun  + '-wpt-firstView.json.gz'
+    - const tracePath = 'data/trace-' + wptRun  + '-wpt-firstView.json.gz'
     a.button.button-download(href=tracePath, download=downloadName + 'trace-' + wptRun  + '-wpt-firstView.json.gz') Download first view timeline
     if wpt.repeatView
-      - var tracePathRepeat = 'data/trace-' + wptRun  + '-wpt-repeatView.json.gz'
+      - const tracePathRepeat = 'data/trace-' + wptRun  + '-wpt-repeatView.json.gz'
       a.button.button-download(href=tracePathRepeat, download=downloadName + 'trace-' + wptRun  + '-wpt-repeatView.json.gz') Download repeat view timeline
 
 each view in ['firstView', 'repeatView']
-  - var median = wpt[view];
+  - const median = wpt[view];
   if median
     h2 #{view === 'firstView' ? 'First View': 'Repeat View'}
     if options.webpagetest.video
@@ -127,7 +127,7 @@ each view in ['firstView', 'repeatView']
             table
               tr
                 th(colspan='2') Visual Progress
-                - var lastProgress = -1
+                - let lastProgress = -1
               each frame in median.videoFrames
                 if lastProgress !== frame.VisuallyComplete
                   - lastProgress = frame.VisuallyComplete
diff --git a/lib/support/helpers/time.js b/lib/support/helpers/time.js
index e66a2238a..eb56132dc 100644
--- a/lib/support/helpers/time.js
+++ b/lib/support/helpers/time.js
@@ -8,7 +8,7 @@ module.exports = {
       return '';
     }
 
-    var secondsPerYear = 365 * 24 * 60 * 60,
+    const secondsPerYear = 365 * 24 * 60 * 60,
       secondsPerWeek = 60 * 60 * 24 * 7,
       secondsPerDay = 60 * 60 * 24,
       secondsPerHour = 60 * 60,
diff --git a/test/graphiteTests.js b/test/graphiteTests.js
index b9b411569..1bde752a4 100644
--- a/test/graphiteTests.js
+++ b/test/graphiteTests.js
@@ -31,7 +31,7 @@ describe('graphite', function() {
         connectivity: 'cable'
       });
 
-      var data = generator.dataFromMessage(message, dayjs());
+      const data = generator.dataFromMessage(message, dayjs());
       expect(data).to.match(/ns.pageSummary.sub_domain_com/);
       expect(data).to.match(/bar.gpsi.median/);
       expect(data).to.match(/foo_bar/);
@@ -63,7 +63,7 @@ describe('graphite', function() {
         browser: 'chrome',
         connectivity: 'cable'
       });
-      var data = generator.dataFromMessage(message, dayjs());
+      const data = generator.dataFromMessage(message, dayjs());
 
       expect(data).to.match(
         /ns.summary.sub_domain_com.chrome.cable.domains.www.sitespeed.io.dns.median [\d]{1,} [\d]*/
@@ -97,7 +97,7 @@ describe('graphite', function() {
         connectivity: 'cable',
         graphite: { statsd: true }
       });
-      var data = generator.dataFromMessage(message, dayjs());
+      const data = generator.dataFromMessage(message, dayjs());
 
       data.forEach(function(line) {
         expect(line).to.match(
diff --git a/test/helpers/first.js b/test/helpers/first.js
index 37af579df..70586e287 100644
--- a/test/helpers/first.js
+++ b/test/helpers/first.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var Bluebird = require('bluebird'),
+const Bluebird = require('bluebird'),
   chai = require('chai'),
   chaiAsPromised = require('chai-as-promised');
 
diff --git a/test/influxdbTests.js b/test/influxdbTests.js
index d7b560729..162c1ccaf 100644
--- a/test/influxdbTests.js
+++ b/test/influxdbTests.js
@@ -354,7 +354,7 @@ describe('influxdb', function() {
         }
       });
 
-      var data = generator.dataFromMessage(message, dayjs());
+      const data = generator.dataFromMessage(message, dayjs());
 
       expect(data).to.not.be.empty;
 
diff --git a/tools/tcp-server.js b/tools/tcp-server.js
index 8d25713e5..736f07feb 100755
--- a/tools/tcp-server.js
+++ b/tools/tcp-server.js
@@ -1,15 +1,15 @@
 #!/usr/bin/env node
 /*eslint no-console: 0*/
 
-var net = require('net');
+const net = require('net');
 
-var server = net
+const server = net
   .createServer(function(sock) {
     sock.on('data', function(data) {
       console.log(data.toString());
     });
   })
   .listen(process.argv[2] || 0, undefined, undefined, () => {
-    var address = server.address();
+    const address = server.address();
     console.log('Server listening on ' + address.address + ':' + address.port);
   });