diff --git a/examples/.eslintrc b/examples/.eslintrc
index 433abdbfa..14eeee2f8 100644
--- a/examples/.eslintrc
+++ b/examples/.eslintrc
@@ -8,4 +8,9 @@
     "pdfjsLib": false,
     "pdfjsViewer": false,
   },
+
+  "rules": {
+    // ECMAScript 6
+    "no-var": "error",
+  },
 }
diff --git a/examples/browserify/gulpfile.js b/examples/browserify/gulpfile.js
index 7d836e78f..15661bbfd 100644
--- a/examples/browserify/gulpfile.js
+++ b/examples/browserify/gulpfile.js
@@ -1,12 +1,12 @@
-var gulp = require("gulp");
-var browserify = require("browserify");
-var streamify = require("gulp-streamify");
-var rename = require("gulp-rename");
-var uglify = require("gulp-uglify");
-var source = require("vinyl-source-stream");
+const gulp = require("gulp");
+const browserify = require("browserify");
+const streamify = require("gulp-streamify");
+const rename = require("gulp-rename");
+const uglify = require("gulp-uglify");
+const source = require("vinyl-source-stream");
 
-var OUTPUT_PATH = "../../build/browserify";
-var TMP_FILE_PREFIX = "../../build/browserify_";
+const OUTPUT_PATH = "../../build/browserify";
+const TMP_FILE_PREFIX = "../../build/browserify_";
 
 gulp.task("build-bundle", function () {
   return browserify("main.js", { output: TMP_FILE_PREFIX + "main.tmp" })
@@ -20,7 +20,7 @@ gulp.task("build-bundle", function () {
 
 gulp.task("build-worker", function () {
   // We can create our own viewer (see worker.js) or use already defined one.
-  var workerSrc = require.resolve("pdfjs-dist/build/pdf.worker.entry");
+  const workerSrc = require.resolve("pdfjs-dist/build/pdf.worker.entry");
   return browserify(workerSrc, { output: TMP_FILE_PREFIX + "worker.tmp" })
     .bundle()
     .pipe(source(TMP_FILE_PREFIX + "worker.tmp"))
diff --git a/examples/browserify/main.js b/examples/browserify/main.js
index 585bffe2a..f033660ef 100644
--- a/examples/browserify/main.js
+++ b/examples/browserify/main.js
@@ -3,27 +3,27 @@
 
 // Hello world example for browserify.
 
-var pdfjsLib = require("pdfjs-dist");
+const pdfjsLib = require("pdfjs-dist");
 
-var pdfPath = "../learning/helloworld.pdf";
+const pdfPath = "../learning/helloworld.pdf";
 
 // Setting worker path to worker bundle.
 pdfjsLib.GlobalWorkerOptions.workerSrc =
   "../../build/browserify/pdf.worker.bundle.js";
 
 // Loading a document.
-var loadingTask = pdfjsLib.getDocument(pdfPath);
+const loadingTask = pdfjsLib.getDocument(pdfPath);
 loadingTask.promise
   .then(function (pdfDocument) {
     // Request a first page
     return pdfDocument.getPage(1).then(function (pdfPage) {
       // Display page on the existing canvas with 100% scale.
-      var viewport = pdfPage.getViewport({ scale: 1.0 });
-      var canvas = document.getElementById("theCanvas");
+      const viewport = pdfPage.getViewport({ scale: 1.0 });
+      const canvas = document.getElementById("theCanvas");
       canvas.width = viewport.width;
       canvas.height = viewport.height;
-      var ctx = canvas.getContext("2d");
-      var renderTask = pdfPage.render({
+      const ctx = canvas.getContext("2d");
+      const renderTask = pdfPage.render({
         canvasContext: ctx,
         viewport,
       });
diff --git a/examples/components/pageviewer.js b/examples/components/pageviewer.js
index 25f99bc97..dfd82dacc 100644
--- a/examples/components/pageviewer.js
+++ b/examples/components/pageviewer.js
@@ -27,19 +27,19 @@ pdfjsLib.GlobalWorkerOptions.workerSrc =
 
 // Some PDFs need external cmaps.
 //
-var CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
-var CMAP_PACKED = true;
+const CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
+const CMAP_PACKED = true;
 
-var DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
-var PAGE_TO_VIEW = 1;
-var SCALE = 1.0;
+const DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
+const PAGE_TO_VIEW = 1;
+const SCALE = 1.0;
 
-var container = document.getElementById("pageContainer");
+const container = document.getElementById("pageContainer");
 
-var eventBus = new pdfjsViewer.EventBus();
+const eventBus = new pdfjsViewer.EventBus();
 
 // Loading document.
-var loadingTask = pdfjsLib.getDocument({
+const loadingTask = pdfjsLib.getDocument({
   url: DEFAULT_URL,
   cMapUrl: CMAP_URL,
   cMapPacked: CMAP_PACKED,
@@ -48,7 +48,7 @@ loadingTask.promise.then(function (pdfDocument) {
   // Document loaded, retrieving the page.
   return pdfDocument.getPage(PAGE_TO_VIEW).then(function (pdfPage) {
     // Creating the page view with default parameters.
-    var pdfPageView = new pdfjsViewer.PDFPageView({
+    const pdfPageView = new pdfjsViewer.PDFPageView({
       container,
       id: PAGE_TO_VIEW,
       scale: SCALE,
diff --git a/examples/components/simpleviewer.js b/examples/components/simpleviewer.js
index 17ab72f46..2c9853046 100644
--- a/examples/components/simpleviewer.js
+++ b/examples/components/simpleviewer.js
@@ -27,40 +27,40 @@ pdfjsLib.GlobalWorkerOptions.workerSrc =
 
 // Some PDFs need external cmaps.
 //
-var CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
-var CMAP_PACKED = true;
+const CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
+const CMAP_PACKED = true;
 
-var DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
+const DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
 // To test the AcroForm and/or scripting functionality, try e.g. this file:
 // var DEFAULT_URL = "../../test/pdfs/160F-2019.pdf";
 
-var SEARCH_FOR = ""; // try 'Mozilla';
+const SEARCH_FOR = ""; // try 'Mozilla';
 
 // For scripting support, note also `enableScripting` below.
-var SANDBOX_BUNDLE_SRC = "../../node_modules/pdfjs-dist/build/pdf.sandbox.js";
+const SANDBOX_BUNDLE_SRC = "../../node_modules/pdfjs-dist/build/pdf.sandbox.js";
 
-var container = document.getElementById("viewerContainer");
+const container = document.getElementById("viewerContainer");
 
-var eventBus = new pdfjsViewer.EventBus();
+const eventBus = new pdfjsViewer.EventBus();
 
 // (Optionally) enable hyperlinks within PDF files.
-var pdfLinkService = new pdfjsViewer.PDFLinkService({
+const pdfLinkService = new pdfjsViewer.PDFLinkService({
   eventBus,
 });
 
 // (Optionally) enable find controller.
-var pdfFindController = new pdfjsViewer.PDFFindController({
+const pdfFindController = new pdfjsViewer.PDFFindController({
   eventBus,
   linkService: pdfLinkService,
 });
 
 // (Optionally) enable scripting support.
-var pdfScriptingManager = new pdfjsViewer.PDFScriptingManager({
+const pdfScriptingManager = new pdfjsViewer.PDFScriptingManager({
   eventBus,
   sandboxBundleSrc: SANDBOX_BUNDLE_SRC,
 });
 
-var pdfViewer = new pdfjsViewer.PDFViewer({
+const pdfViewer = new pdfjsViewer.PDFViewer({
   container,
   eventBus,
   linkService: pdfLinkService,
@@ -82,7 +82,7 @@ eventBus.on("pagesinit", function () {
 });
 
 // Loading document.
-var loadingTask = pdfjsLib.getDocument({
+const loadingTask = pdfjsLib.getDocument({
   url: DEFAULT_URL,
   cMapUrl: CMAP_URL,
   cMapPacked: CMAP_PACKED,
diff --git a/examples/components/singlepageviewer.js b/examples/components/singlepageviewer.js
index d8ece8ef6..821ef2214 100644
--- a/examples/components/singlepageviewer.js
+++ b/examples/components/singlepageviewer.js
@@ -27,40 +27,40 @@ pdfjsLib.GlobalWorkerOptions.workerSrc =
 
 // Some PDFs need external cmaps.
 //
-var CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
-var CMAP_PACKED = true;
+const CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
+const CMAP_PACKED = true;
 
-var DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
+const DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
 // To test the AcroForm and/or scripting functionality, try e.g. this file:
 // var DEFAULT_URL = "../../test/pdfs/160F-2019.pdf";
 
-var SEARCH_FOR = ""; // try 'Mozilla';
+const SEARCH_FOR = ""; // try 'Mozilla';
 
 // For scripting support, note also `enableScripting` below.
-var SANDBOX_BUNDLE_SRC = "../../node_modules/pdfjs-dist/build/pdf.sandbox.js";
+const SANDBOX_BUNDLE_SRC = "../../node_modules/pdfjs-dist/build/pdf.sandbox.js";
 
-var container = document.getElementById("viewerContainer");
+const container = document.getElementById("viewerContainer");
 
-var eventBus = new pdfjsViewer.EventBus();
+const eventBus = new pdfjsViewer.EventBus();
 
 // (Optionally) enable hyperlinks within PDF files.
-var pdfLinkService = new pdfjsViewer.PDFLinkService({
+const pdfLinkService = new pdfjsViewer.PDFLinkService({
   eventBus,
 });
 
 // (Optionally) enable find controller.
-var pdfFindController = new pdfjsViewer.PDFFindController({
+const pdfFindController = new pdfjsViewer.PDFFindController({
   eventBus,
   linkService: pdfLinkService,
 });
 
 // (Optionally) enable scripting support.
-var pdfScriptingManager = new pdfjsViewer.PDFScriptingManager({
+const pdfScriptingManager = new pdfjsViewer.PDFScriptingManager({
   eventBus,
   sandboxBundleSrc: SANDBOX_BUNDLE_SRC,
 });
 
-var pdfSinglePageViewer = new pdfjsViewer.PDFSinglePageViewer({
+const pdfSinglePageViewer = new pdfjsViewer.PDFSinglePageViewer({
   container,
   eventBus,
   linkService: pdfLinkService,
@@ -82,7 +82,7 @@ eventBus.on("pagesinit", function () {
 });
 
 // Loading document.
-var loadingTask = pdfjsLib.getDocument({
+const loadingTask = pdfjsLib.getDocument({
   url: DEFAULT_URL,
   cMapUrl: CMAP_URL,
   cMapPacked: CMAP_PACKED,
diff --git a/examples/image_decoders/jpeg_viewer.js b/examples/image_decoders/jpeg_viewer.js
index 31008ff19..474b48744 100644
--- a/examples/image_decoders/jpeg_viewer.js
+++ b/examples/image_decoders/jpeg_viewer.js
@@ -20,15 +20,15 @@ if (!pdfjsImageDecoders.JpegImage) {
   alert("Please build the pdfjs-dist library using `gulp dist-install`");
 }
 
-var JPEG_IMAGE = "fish.jpg";
+const JPEG_IMAGE = "fish.jpg";
 
-var jpegCanvas = document.getElementById("jpegCanvas");
-var jpegCtx = jpegCanvas.getContext("2d");
+const jpegCanvas = document.getElementById("jpegCanvas");
+const jpegCtx = jpegCanvas.getContext("2d");
 
 // Load the image data, and convert it to a Uint8Array.
 //
-var nonBinaryRequest = false;
-var request = new XMLHttpRequest();
+let nonBinaryRequest = false;
+const request = new XMLHttpRequest();
 request.open("GET", JPEG_IMAGE, false);
 try {
   request.responseType = "arraybuffer";
@@ -41,12 +41,12 @@ if (nonBinaryRequest && request.overrideMimeType) {
 }
 request.send(null);
 
-var typedArrayImage;
+let typedArrayImage;
 if (nonBinaryRequest) {
-  var str = request.responseText,
+  const str = request.responseText,
     length = str.length;
-  var bytes = new Uint8Array(length);
-  for (var i = 0; i < length; ++i) {
+  const bytes = new Uint8Array(length);
+  for (let i = 0; i < length; ++i) {
     bytes[i] = str.charCodeAt(i) & 0xff;
   }
   typedArrayImage = bytes;
@@ -56,12 +56,12 @@ if (nonBinaryRequest) {
 
 // Parse the image data using `JpegImage`.
 //
-var jpegImage = new pdfjsImageDecoders.JpegImage();
+const jpegImage = new pdfjsImageDecoders.JpegImage();
 jpegImage.parse(typedArrayImage);
 
-var width = jpegImage.width,
+const width = jpegImage.width,
   height = jpegImage.height;
-var jpegData = jpegImage.getData({
+const jpegData = jpegImage.getData({
   width,
   height,
   forceRGB: true,
@@ -69,9 +69,9 @@ var jpegData = jpegImage.getData({
 
 // Render the JPEG image on a <canvas>.
 //
-var imageData = jpegCtx.createImageData(width, height);
-var imageBytes = imageData.data;
-for (var j = 0, k = 0, jj = width * height * 4; j < jj; ) {
+const imageData = jpegCtx.createImageData(width, height);
+const imageBytes = imageData.data;
+for (let j = 0, k = 0, jj = width * height * 4; j < jj; ) {
   imageBytes[j++] = jpegData[k++];
   imageBytes[j++] = jpegData[k++];
   imageBytes[j++] = jpegData[k++];
diff --git a/examples/mobile-viewer/viewer.js b/examples/mobile-viewer/viewer.js
index fe0b84efd..18b28688c 100644
--- a/examples/mobile-viewer/viewer.js
+++ b/examples/mobile-viewer/viewer.js
@@ -20,22 +20,22 @@ if (!pdfjsLib.getDocument || !pdfjsViewer.PDFViewer) {
   alert("Please build the pdfjs-dist library using\n `gulp dist-install`");
 }
 
-var USE_ONLY_CSS_ZOOM = true;
-var TEXT_LAYER_MODE = 0; // DISABLE
-var MAX_IMAGE_SIZE = 1024 * 1024;
-var CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
-var CMAP_PACKED = true;
+const USE_ONLY_CSS_ZOOM = true;
+const TEXT_LAYER_MODE = 0; // DISABLE
+const MAX_IMAGE_SIZE = 1024 * 1024;
+const CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
+const CMAP_PACKED = true;
 
 pdfjsLib.GlobalWorkerOptions.workerSrc =
   "../../node_modules/pdfjs-dist/build/pdf.worker.js";
 
-var DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
-var DEFAULT_SCALE_DELTA = 1.1;
-var MIN_SCALE = 0.25;
-var MAX_SCALE = 10.0;
-var DEFAULT_SCALE_VALUE = "auto";
+const DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
+const DEFAULT_SCALE_DELTA = 1.1;
+const MIN_SCALE = 0.25;
+const MAX_SCALE = 10.0;
+const DEFAULT_SCALE_VALUE = "auto";
 
-var PDFViewerApplication = {
+const PDFViewerApplication = {
   pdfLoadingTask: null,
   pdfDocument: null,
   pdfViewer: null,
@@ -59,12 +59,12 @@ var PDFViewerApplication = {
       );
     }
 
-    var url = params.url;
-    var self = this;
+    const url = params.url;
+    const self = this;
     this.setTitleUsingUrl(url);
 
     // Loading document.
-    var loadingTask = pdfjsLib.getDocument({
+    const loadingTask = pdfjsLib.getDocument({
       url,
       maxImageSize: MAX_IMAGE_SIZE,
       cMapUrl: CMAP_URL,
@@ -88,9 +88,9 @@ var PDFViewerApplication = {
         self.setTitleUsingMetadata(pdfDocument);
       },
       function (exception) {
-        var message = exception && exception.message;
-        var l10n = self.l10n;
-        var loadingErrorMessage;
+        const message = exception && exception.message;
+        const l10n = self.l10n;
+        let loadingErrorMessage;
 
         if (exception instanceof pdfjsLib.InvalidPDFException) {
           // change error message also for other builds
@@ -134,14 +134,14 @@ var PDFViewerApplication = {
    *                      destruction is completed.
    */
   close() {
-    var errorWrapper = document.getElementById("errorWrapper");
+    const errorWrapper = document.getElementById("errorWrapper");
     errorWrapper.hidden = true;
 
     if (!this.pdfLoadingTask) {
       return Promise.resolve();
     }
 
-    var promise = this.pdfLoadingTask.destroy();
+    const promise = this.pdfLoadingTask.destroy();
     this.pdfLoadingTask = null;
 
     if (this.pdfDocument) {
@@ -159,14 +159,14 @@ var PDFViewerApplication = {
   },
 
   get loadingBar() {
-    var bar = new pdfjsViewer.ProgressBar("#loadingBar", {});
+    const bar = new pdfjsViewer.ProgressBar("#loadingBar", {});
 
     return pdfjsLib.shadow(this, "loadingBar", bar);
   },
 
   setTitleUsingUrl: function pdfViewSetTitleUsingUrl(url) {
     this.url = url;
-    var title = pdfjsLib.getFilenameFromUrl(url) || url;
+    let title = pdfjsLib.getFilenameFromUrl(url) || url;
     try {
       title = decodeURIComponent(title);
     } catch (e) {
@@ -177,9 +177,9 @@ var PDFViewerApplication = {
   },
 
   setTitleUsingMetadata(pdfDocument) {
-    var self = this;
+    const self = this;
     pdfDocument.getMetadata().then(function (data) {
-      var info = data.info,
+      const info = data.info,
         metadata = data.metadata;
       self.documentInfo = info;
       self.metadata = metadata;
@@ -200,9 +200,9 @@ var PDFViewerApplication = {
           ")"
       );
 
-      var pdfTitle;
+      let pdfTitle;
       if (metadata && metadata.has("dc:title")) {
-        var title = metadata.get("dc:title");
+        const title = metadata.get("dc:title");
         // Ghostscript sometimes returns 'Untitled', so prevent setting the
         // title to 'Untitled.
         if (title !== "Untitled") {
@@ -226,8 +226,8 @@ var PDFViewerApplication = {
   },
 
   error: function pdfViewError(message, moreInfo) {
-    var l10n = this.l10n;
-    var moreInfoText = [
+    const l10n = this.l10n;
+    const moreInfoText = [
       l10n.get(
         "error_version_info",
         { version: pdfjsLib.version || "?", build: pdfjsLib.build || "?" },
@@ -269,20 +269,20 @@ var PDFViewerApplication = {
       }
     }
 
-    var errorWrapper = document.getElementById("errorWrapper");
+    const errorWrapper = document.getElementById("errorWrapper");
     errorWrapper.hidden = false;
 
-    var errorMessage = document.getElementById("errorMessage");
+    const errorMessage = document.getElementById("errorMessage");
     errorMessage.textContent = message;
 
-    var closeButton = document.getElementById("errorClose");
+    const closeButton = document.getElementById("errorClose");
     closeButton.onclick = function () {
       errorWrapper.hidden = true;
     };
 
-    var errorMoreInfo = document.getElementById("errorMoreInfo");
-    var moreInfoButton = document.getElementById("errorShowMore");
-    var lessInfoButton = document.getElementById("errorShowLess");
+    const errorMoreInfo = document.getElementById("errorMoreInfo");
+    const moreInfoButton = document.getElementById("errorShowMore");
+    const lessInfoButton = document.getElementById("errorShowLess");
     moreInfoButton.onclick = function () {
       errorMoreInfo.hidden = false;
       moreInfoButton.hidden = true;
@@ -302,7 +302,7 @@ var PDFViewerApplication = {
   },
 
   progress: function pdfViewProgress(level) {
-    var percent = Math.round(level * 100);
+    const percent = Math.round(level * 100);
     // Updating the bar if value increases.
     if (percent > this.loadingBar.percent || isNaN(percent)) {
       this.loadingBar.percent = percent;
@@ -322,7 +322,7 @@ var PDFViewerApplication = {
   },
 
   zoomIn: function pdfViewZoomIn(ticks) {
-    var newScale = this.pdfViewer.currentScale;
+    let newScale = this.pdfViewer.currentScale;
     do {
       newScale = (newScale * DEFAULT_SCALE_DELTA).toFixed(2);
       newScale = Math.ceil(newScale * 10) / 10;
@@ -332,7 +332,7 @@ var PDFViewerApplication = {
   },
 
   zoomOut: function pdfViewZoomOut(ticks) {
-    var newScale = this.pdfViewer.currentScale;
+    let newScale = this.pdfViewer.currentScale;
     do {
       newScale = (newScale / DEFAULT_SCALE_DELTA).toFixed(2);
       newScale = Math.floor(newScale * 10) / 10;
@@ -342,18 +342,18 @@ var PDFViewerApplication = {
   },
 
   initUI: function pdfViewInitUI() {
-    var eventBus = new pdfjsViewer.EventBus();
+    const eventBus = new pdfjsViewer.EventBus();
     this.eventBus = eventBus;
 
-    var linkService = new pdfjsViewer.PDFLinkService({
+    const linkService = new pdfjsViewer.PDFLinkService({
       eventBus,
     });
     this.pdfLinkService = linkService;
 
     this.l10n = pdfjsViewer.NullL10n;
 
-    var container = document.getElementById("viewerContainer");
-    var pdfViewer = new pdfjsViewer.PDFViewer({
+    const container = document.getElementById("viewerContainer");
+    const pdfViewer = new pdfjsViewer.PDFViewer({
       container,
       eventBus,
       linkService,
@@ -413,8 +413,8 @@ var PDFViewerApplication = {
     eventBus.on(
       "pagechanging",
       function (evt) {
-        var page = evt.pageNumber;
-        var numPages = PDFViewerApplication.pagesCount;
+        const page = evt.pageNumber;
+        const numPages = PDFViewerApplication.pagesCount;
 
         document.getElementById("pageNumber").value = page;
         document.getElementById("previous").disabled = page <= 1;
@@ -425,6 +425,8 @@ var PDFViewerApplication = {
   },
 };
 
+window.PDFViewerApplication = PDFViewerApplication;
+
 document.addEventListener(
   "DOMContentLoaded",
   function () {
@@ -433,18 +435,14 @@ document.addEventListener(
   true
 );
 
-(function animationStartedClosure() {
-  // The offsetParent is not set until the PDF.js iframe or object is visible.
-  // Waiting for first animation.
-  PDFViewerApplication.animationStartedPromise = new Promise(function (
-    resolve
-  ) {
-    window.requestAnimationFrame(resolve);
-  });
-})();
+// The offsetParent is not set until the PDF.js iframe or object is visible;
+// waiting for first animation.
+const animationStarted = new Promise(function (resolve) {
+  window.requestAnimationFrame(resolve);
+});
 
 // We need to delay opening until all HTML is loaded.
-PDFViewerApplication.animationStartedPromise.then(function () {
+animationStarted.then(function () {
   PDFViewerApplication.open({
     url: DEFAULT_URL,
   });
diff --git a/examples/node/domstubs.js b/examples/node/domstubs.js
index 1f5b98d48..1d1039a0b 100644
--- a/examples/node/domstubs.js
+++ b/examples/node/domstubs.js
@@ -2,7 +2,7 @@
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 function xmlEncode(s) {
-  var i = 0,
+  let i = 0,
     ch;
   s = String(s);
   while (
@@ -19,7 +19,7 @@ function xmlEncode(s) {
   if (i >= s.length) {
     return s;
   }
-  var buf = s.substring(0, i);
+  let buf = s.substring(0, i);
   while (i < s.length) {
     ch = s[i++];
     switch (ch) {
@@ -82,8 +82,8 @@ DOMElement.prototype = {
     // Assuming that there is only one matching attribute for a given name,
     // across all namespaces.
     if (NS) {
-      var suffix = ":" + name;
-      for (var fullName in this.attributes) {
+      const suffix = ":" + name;
+      for (const fullName in this.attributes) {
         if (fullName.slice(-suffix.length) === suffix) {
           return this.attributes[fullName];
         }
@@ -103,7 +103,7 @@ DOMElement.prototype = {
   },
 
   appendChild: function DOMElement_appendChild(element) {
-    var childNodes = this.childNodes;
+    const childNodes = this.childNodes;
     if (!childNodes.includes(element)) {
       childNodes.push(element);
     }
@@ -114,7 +114,7 @@ DOMElement.prototype = {
   },
 
   cloneNode: function DOMElement_cloneNode() {
-    var newNode = new DOMElement(this.nodeName);
+    const newNode = new DOMElement(this.nodeName);
     newNode.childNodes = this.childNodes;
     newNode.attributes = this.attributes;
     newNode.textContent = this.textContent;
@@ -125,9 +125,9 @@ DOMElement.prototype = {
   // getSerializer because that allows you to process the chunks as they come
   // instead of requiring the whole image to fit in memory.
   toString: function DOMElement_toString() {
-    var buf = [];
-    var serializer = this.getSerializer();
-    var chunk;
+    const buf = [];
+    const serializer = this.getSerializer();
+    let chunk;
     while ((chunk = serializer.getNext()) !== null) {
       buf.push(chunk);
     }
@@ -153,7 +153,7 @@ DOMElementSerializer.prototype = {
    * @returns {string|null} null if the element has fully been serialized.
    */
   getNext: function DOMElementSerializer_getNext() {
-    var node = this._node;
+    const node = this._node;
     switch (this._state) {
       case 0: // Start opening tag.
         ++this._state;
@@ -174,7 +174,7 @@ DOMElementSerializer.prototype = {
       /* falls through */
       case 3: // Serialize any attributes and end opening tag.
         if (this._loopIndex < this._attributeKeys.length) {
-          var name = this._attributeKeys[this._loopIndex++];
+          const name = this._attributeKeys[this._loopIndex++];
           return " " + name + '="' + xmlEncode(node.attributes[name]) + '"';
         }
         ++this._state;
@@ -188,13 +188,13 @@ DOMElementSerializer.prototype = {
         this._loopIndex = 0;
       /* falls through */
       case 5: // Serialize child nodes (only for non-tspan/style elements).
-        var value;
         while (true) {
-          value = this._childSerializer && this._childSerializer.getNext();
+          const value =
+            this._childSerializer && this._childSerializer.getNext();
           if (value !== null) {
             return value;
           }
-          var nextChild = node.childNodes[this._loopIndex++];
+          const nextChild = node.childNodes[this._loopIndex++];
           if (nextChild) {
             this._childSerializer = new DOMElementSerializer(nextChild);
           } else {
@@ -227,7 +227,7 @@ const document = {
   },
 
   createElementNS(NS, element) {
-    var elObject = new DOMElement(element);
+    const elObject = new DOMElement(element);
     return elObject;
   },
 
@@ -262,7 +262,7 @@ Image.prototype = {
 exports.document = document;
 exports.Image = Image;
 
-var exported_symbols = Object.keys(exports);
+const exported_symbols = Object.keys(exports);
 
 exports.setStubs = function (namespace) {
   exported_symbols.forEach(function (key) {
diff --git a/examples/node/getinfo.js b/examples/node/getinfo.js
index fccb984c5..944f9e930 100644
--- a/examples/node/getinfo.js
+++ b/examples/node/getinfo.js
@@ -8,22 +8,23 @@
 //
 
 // Run `gulp dist-install` to generate 'pdfjs-dist' npm package files.
-var pdfjsLib = require("pdfjs-dist/legacy/build/pdf.js");
+const pdfjsLib = require("pdfjs-dist/legacy/build/pdf.js");
 
 // Loading file from file system into typed array
-var pdfPath = process.argv[2] || "../../web/compressed.tracemonkey-pldi-09.pdf";
+const pdfPath =
+  process.argv[2] || "../../web/compressed.tracemonkey-pldi-09.pdf";
 
 // Will be using promises to load document, pages and misc data instead of
 // callback.
-var loadingTask = pdfjsLib.getDocument(pdfPath);
+const loadingTask = pdfjsLib.getDocument(pdfPath);
 loadingTask.promise
   .then(function (doc) {
-    var numPages = doc.numPages;
+    const numPages = doc.numPages;
     console.log("# Document Loaded");
     console.log("Number of Pages: " + numPages);
     console.log();
 
-    var lastPromise; // will be used to chain promises
+    let lastPromise; // will be used to chain promises
     lastPromise = doc.getMetadata().then(function (data) {
       console.log("# Metadata Is Loaded");
       console.log("## Info");
@@ -36,10 +37,10 @@ loadingTask.promise
       }
     });
 
-    var loadPage = function (pageNum) {
+    const loadPage = function (pageNum) {
       return doc.getPage(pageNum).then(function (page) {
         console.log("# Page " + pageNum);
-        var viewport = page.getViewport({ scale: 1.0 });
+        const viewport = page.getViewport({ scale: 1.0 });
         console.log("Size: " + viewport.width + "x" + viewport.height);
         console.log();
         return page
@@ -47,7 +48,7 @@ loadingTask.promise
           .then(function (content) {
             // Content contains lots of information about the text layout and
             // styles, but we need only strings at the moment
-            var strings = content.items.map(function (item) {
+            const strings = content.items.map(function (item) {
               return item.str;
             });
             console.log("## Text Content");
@@ -60,7 +61,7 @@ loadingTask.promise
     };
     // Loading of the first page will wait on metadata and subsequent loadings
     // will wait on the previous pages.
-    for (var i = 1; i <= numPages; i++) {
+    for (let i = 1; i <= numPages; i++) {
       lastPromise = lastPromise.then(loadPage.bind(null, i));
     }
     return lastPromise;
diff --git a/examples/node/pdf2png/pdf2png.js b/examples/node/pdf2png/pdf2png.js
index 423533001..aa61ef57e 100644
--- a/examples/node/pdf2png/pdf2png.js
+++ b/examples/node/pdf2png/pdf2png.js
@@ -13,16 +13,16 @@
  * limitations under the License.
  */
 
-var Canvas = require("canvas");
-var assert = require("assert").strict;
-var fs = require("fs");
+const Canvas = require("canvas");
+const assert = require("assert").strict;
+const fs = require("fs");
 
 function NodeCanvasFactory() {}
 NodeCanvasFactory.prototype = {
   create: function NodeCanvasFactory_create(width, height) {
     assert(width > 0 && height > 0, "Invalid canvas size");
-    var canvas = Canvas.createCanvas(width, height);
-    var context = canvas.getContext("2d");
+    const canvas = Canvas.createCanvas(width, height);
+    const context = canvas.getContext("2d");
     return {
       canvas,
       context,
@@ -48,19 +48,19 @@ NodeCanvasFactory.prototype = {
   },
 };
 
-var pdfjsLib = require("pdfjs-dist/legacy/build/pdf.js");
+const pdfjsLib = require("pdfjs-dist/legacy/build/pdf.js");
 
 // Some PDFs need external cmaps.
-var CMAP_URL = "../../../node_modules/pdfjs-dist/cmaps/";
-var CMAP_PACKED = true;
+const CMAP_URL = "../../../node_modules/pdfjs-dist/cmaps/";
+const CMAP_PACKED = true;
 
 // Loading file from file system into typed array.
-var pdfPath =
+const pdfPath =
   process.argv[2] || "../../../web/compressed.tracemonkey-pldi-09.pdf";
-var data = new Uint8Array(fs.readFileSync(pdfPath));
+const data = new Uint8Array(fs.readFileSync(pdfPath));
 
 // Load the PDF file.
-var loadingTask = pdfjsLib.getDocument({
+const loadingTask = pdfjsLib.getDocument({
   data,
   cMapUrl: CMAP_URL,
   cMapPacked: CMAP_PACKED,
@@ -72,22 +72,22 @@ loadingTask.promise
     // Get the first page.
     pdfDocument.getPage(1).then(function (page) {
       // Render the page on a Node canvas with 100% scale.
-      var viewport = page.getViewport({ scale: 1.0 });
-      var canvasFactory = new NodeCanvasFactory();
-      var canvasAndContext = canvasFactory.create(
+      const viewport = page.getViewport({ scale: 1.0 });
+      const canvasFactory = new NodeCanvasFactory();
+      const canvasAndContext = canvasFactory.create(
         viewport.width,
         viewport.height
       );
-      var renderContext = {
+      const renderContext = {
         canvasContext: canvasAndContext.context,
         viewport,
         canvasFactory,
       };
 
-      var renderTask = page.render(renderContext);
+      const renderTask = page.render(renderContext);
       renderTask.promise.then(function () {
         // Convert the canvas to an image buffer.
-        var image = canvasAndContext.canvas.toBuffer();
+        const image = canvasAndContext.canvas.toBuffer();
         fs.writeFile("output.png", image, function (error) {
           if (error) {
             console.error("Error: " + error);
diff --git a/examples/node/pdf2svg.js b/examples/node/pdf2svg.js
index f5b307023..dea014f4d 100644
--- a/examples/node/pdf2svg.js
+++ b/examples/node/pdf2svg.js
@@ -5,26 +5,27 @@
 // Node tool to dump SVG output into a file.
 //
 
-var fs = require("fs");
-var util = require("util");
-var path = require("path");
-var stream = require("stream");
+const fs = require("fs");
+const util = require("util");
+const path = require("path");
+const stream = require("stream");
 
 // HACK few hacks to let PDF.js be loaded not as a module in global space.
 require("./domstubs.js").setStubs(global);
 
 // Run `gulp dist-install` to generate 'pdfjs-dist' npm package files.
-var pdfjsLib = require("pdfjs-dist/legacy/build/pdf.js");
+const pdfjsLib = require("pdfjs-dist/legacy/build/pdf.js");
 
 // Some PDFs need external cmaps.
-var CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
-var CMAP_PACKED = true;
+const CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
+const CMAP_PACKED = true;
 
 // Loading file from file system into typed array
-var pdfPath = process.argv[2] || "../../web/compressed.tracemonkey-pldi-09.pdf";
-var data = new Uint8Array(fs.readFileSync(pdfPath));
+const pdfPath =
+  process.argv[2] || "../../web/compressed.tracemonkey-pldi-09.pdf";
+const data = new Uint8Array(fs.readFileSync(pdfPath));
 
-var outputDirectory = "./svgdump";
+const outputDirectory = "./svgdump";
 
 try {
   // Note: This creates a directory only one level deep. If you want to create
@@ -38,7 +39,7 @@ try {
 
 // Dumps svg outputs to a folder called svgdump
 function getFilePathForPage(pageNum) {
-  var name = path.basename(pdfPath, path.extname(pdfPath));
+  const name = path.basename(pdfPath, path.extname(pdfPath));
   return path.join(outputDirectory, name + "-" + pageNum + ".svg");
 }
 
@@ -59,7 +60,7 @@ function ReadableSVGStream(options) {
 util.inherits(ReadableSVGStream, stream.Readable);
 // Implements https://nodejs.org/api/stream.html#stream_readable_read_size_1
 ReadableSVGStream.prototype._read = function () {
-  var chunk;
+  let chunk;
   while ((chunk = this.serializer.getNext()) !== null) {
     if (!this.push(chunk)) {
       return;
@@ -70,10 +71,10 @@ ReadableSVGStream.prototype._read = function () {
 
 // Streams the SVG element to the given file path.
 function writeSvgToFile(svgElement, filePath) {
-  var readableSvgStream = new ReadableSVGStream({
+  let readableSvgStream = new ReadableSVGStream({
     svgElement,
   });
-  var writableStream = fs.createWriteStream(filePath);
+  const writableStream = fs.createWriteStream(filePath);
   return new Promise(function (resolve, reject) {
     readableSvgStream.once("error", reject);
     writableStream.once("error", reject);
@@ -88,7 +89,7 @@ function writeSvgToFile(svgElement, filePath) {
 
 // Will be using promises to load document, pages and misc data instead of
 // callback.
-var loadingTask = pdfjsLib.getDocument({
+const loadingTask = pdfjsLib.getDocument({
   data,
   cMapUrl: CMAP_URL,
   cMapPacked: CMAP_PACKED,
@@ -96,21 +97,21 @@ var loadingTask = pdfjsLib.getDocument({
 });
 loadingTask.promise
   .then(function (doc) {
-    var numPages = doc.numPages;
+    const numPages = doc.numPages;
     console.log("# Document Loaded");
     console.log("Number of Pages: " + numPages);
     console.log();
 
-    var lastPromise = Promise.resolve(); // will be used to chain promises
-    var loadPage = function (pageNum) {
+    let lastPromise = Promise.resolve(); // will be used to chain promises
+    const loadPage = function (pageNum) {
       return doc.getPage(pageNum).then(function (page) {
         console.log("# Page " + pageNum);
-        var viewport = page.getViewport({ scale: 1.0 });
+        const viewport = page.getViewport({ scale: 1.0 });
         console.log("Size: " + viewport.width + "x" + viewport.height);
         console.log();
 
         return page.getOperatorList().then(function (opList) {
-          var svgGfx = new pdfjsLib.SVGGraphics(page.commonObjs, page.objs);
+          const svgGfx = new pdfjsLib.SVGGraphics(page.commonObjs, page.objs);
           svgGfx.embedFonts = true;
           return svgGfx.getSVG(opList, viewport).then(function (svg) {
             return writeSvgToFile(svg, getFilePathForPage(pageNum)).then(
@@ -126,7 +127,7 @@ loadingTask.promise
       });
     };
 
-    for (var i = 1; i <= numPages; i++) {
+    for (let i = 1; i <= numPages; i++) {
       lastPromise = lastPromise.then(loadPage.bind(null, i));
     }
     return lastPromise;
diff --git a/examples/svgviewer/viewer.js b/examples/svgviewer/viewer.js
index b72ba7825..3fb1307b5 100644
--- a/examples/svgviewer/viewer.js
+++ b/examples/svgviewer/viewer.js
@@ -27,21 +27,21 @@ pdfjsLib.GlobalWorkerOptions.workerSrc =
 
 // Some PDFs need external cmaps.
 //
-var CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
-var CMAP_PACKED = true;
+const CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
+const CMAP_PACKED = true;
 
-var DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
+const DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
 
-var container = document.getElementById("viewerContainer");
+const container = document.getElementById("viewerContainer");
 
-var eventBus = new pdfjsViewer.EventBus();
+const eventBus = new pdfjsViewer.EventBus();
 
 // (Optionally) enable hyperlinks within PDF files.
-var pdfLinkService = new pdfjsViewer.PDFLinkService({
+const pdfLinkService = new pdfjsViewer.PDFLinkService({
   eventBus,
 });
 
-var pdfViewer = new pdfjsViewer.PDFViewer({
+const pdfViewer = new pdfjsViewer.PDFViewer({
   container,
   eventBus,
   linkService: pdfLinkService,
@@ -56,7 +56,7 @@ eventBus.on("pagesinit", function () {
 });
 
 // Loading document.
-var loadingTask = pdfjsLib.getDocument({
+const loadingTask = pdfjsLib.getDocument({
   url: DEFAULT_URL,
   cMapUrl: CMAP_URL,
   cMapPacked: CMAP_PACKED,
diff --git a/examples/text-only/pdf2svg.js b/examples/text-only/pdf2svg.js
index c62954f88..e00e7fbea 100644
--- a/examples/text-only/pdf2svg.js
+++ b/examples/text-only/pdf2svg.js
@@ -13,17 +13,17 @@
  * limitations under the License.
  */
 
-var PDF_PATH = "../../web/compressed.tracemonkey-pldi-09.pdf";
-var PAGE_NUMBER = 1;
-var PAGE_SCALE = 1.5;
-var SVG_NS = "http://www.w3.org/2000/svg";
+const PDF_PATH = "../../web/compressed.tracemonkey-pldi-09.pdf";
+const PAGE_NUMBER = 1;
+const PAGE_SCALE = 1.5;
+const SVG_NS = "http://www.w3.org/2000/svg";
 
 pdfjsLib.GlobalWorkerOptions.workerSrc =
   "../../node_modules/pdfjs-dist/build/pdf.worker.js";
 
 function buildSVG(viewport, textContent) {
   // Building SVG with size of the viewport (for simplicity)
-  var svg = document.createElementNS(SVG_NS, "svg:svg");
+  const svg = document.createElementNS(SVG_NS, "svg:svg");
   svg.setAttribute("width", viewport.width + "px");
   svg.setAttribute("height", viewport.height + "px");
   // items are transformed to have 1px font size
@@ -33,13 +33,13 @@ function buildSVG(viewport, textContent) {
   textContent.items.forEach(function (textItem) {
     // we have to take in account viewport transform, which includes scale,
     // rotation and Y-axis flip, and not forgetting to flip text.
-    var tx = pdfjsLib.Util.transform(
+    const tx = pdfjsLib.Util.transform(
       pdfjsLib.Util.transform(viewport.transform, textItem.transform),
       [1, 0, 0, -1, 0, 0]
     );
-    var style = textContent.styles[textItem.fontName];
+    const style = textContent.styles[textItem.fontName];
     // adding text element
-    var text = document.createElementNS(SVG_NS, "svg:text");
+    const text = document.createElementNS(SVG_NS, "svg:text");
     text.setAttribute("transform", "matrix(" + tx.join(" ") + ")");
     text.setAttribute("font-family", style.fontFamily);
     text.textContent = textItem.str;
@@ -50,13 +50,13 @@ function buildSVG(viewport, textContent) {
 
 function pageLoaded() {
   // Loading document and page text content
-  var loadingTask = pdfjsLib.getDocument({ url: PDF_PATH });
+  const loadingTask = pdfjsLib.getDocument({ url: PDF_PATH });
   loadingTask.promise.then(function (pdfDocument) {
     pdfDocument.getPage(PAGE_NUMBER).then(function (page) {
-      var viewport = page.getViewport({ scale: PAGE_SCALE });
+      const viewport = page.getViewport({ scale: PAGE_SCALE });
       page.getTextContent().then(function (textContent) {
         // building SVG and adding that to the DOM
-        var svg = buildSVG(viewport, textContent);
+        const svg = buildSVG(viewport, textContent);
         document.getElementById("pageContainer").appendChild(svg);
       });
     });
diff --git a/examples/webpack/main.js b/examples/webpack/main.js
index 088358c92..cc1a8be3c 100644
--- a/examples/webpack/main.js
+++ b/examples/webpack/main.js
@@ -3,27 +3,27 @@
 
 // Hello world example for webpack.
 
-var pdfjsLib = require("pdfjs-dist");
+const pdfjsLib = require("pdfjs-dist");
 
-var pdfPath = "../learning/helloworld.pdf";
+const pdfPath = "../learning/helloworld.pdf";
 
 // Setting worker path to worker bundle.
 pdfjsLib.GlobalWorkerOptions.workerSrc =
   "../../build/webpack/pdf.worker.bundle.js";
 
 // Loading a document.
-var loadingTask = pdfjsLib.getDocument(pdfPath);
+const loadingTask = pdfjsLib.getDocument(pdfPath);
 loadingTask.promise
   .then(function (pdfDocument) {
     // Request a first page
     return pdfDocument.getPage(1).then(function (pdfPage) {
       // Display page on the existing canvas with 100% scale.
-      var viewport = pdfPage.getViewport({ scale: 1.0 });
-      var canvas = document.getElementById("theCanvas");
+      const viewport = pdfPage.getViewport({ scale: 1.0 });
+      const canvas = document.getElementById("theCanvas");
       canvas.width = viewport.width;
       canvas.height = viewport.height;
-      var ctx = canvas.getContext("2d");
-      var renderTask = pdfPage.render({
+      const ctx = canvas.getContext("2d");
+      const renderTask = pdfPage.render({
         canvasContext: ctx,
         viewport,
       });
diff --git a/examples/webpack/webpack.config.js b/examples/webpack/webpack.config.js
index 4db8758f3..0dc1be1ae 100644
--- a/examples/webpack/webpack.config.js
+++ b/examples/webpack/webpack.config.js
@@ -1,5 +1,5 @@
-var webpack = require("webpack"); // eslint-disable-line no-unused-vars
-var path = require("path");
+const webpack = require("webpack"); // eslint-disable-line no-unused-vars
+const path = require("path");
 
 module.exports = {
   context: __dirname,