diff --git a/src/static/js/AttributePool.js b/src/static/js/AttributePool.js
index 78d3e7c5b..79849f4d3 100644
--- a/src/static/js/AttributePool.js
+++ b/src/static/js/AttributePool.js
@@ -1,3 +1,4 @@
+'use strict';
 /**
  * This code represents the Attribute Pool Object of the original Etherpad.
  * 90% of the code is still like in the original Etherpad
@@ -69,7 +70,7 @@ AttributePool.prototype.getAttribValue = function (num) {
 };
 
 AttributePool.prototype.eachAttrib = function (func) {
-  for (const n in this.numToAttrib) {
+  for (const n of Object.keys(this.numToAttrib)) {
     const pair = this.numToAttrib[n];
     func(pair[0], pair[1]);
   }
@@ -86,7 +87,7 @@ AttributePool.prototype.fromJsonable = function (obj) {
   this.numToAttrib = obj.numToAttrib;
   this.nextNum = obj.nextNum;
   this.attribToNum = {};
-  for (const n in this.numToAttrib) {
+  for (const n of Object.keys(this.numToAttrib)) {
     this.attribToNum[String(this.numToAttrib[n])] = Number(n);
   }
   return this;
diff --git a/src/static/js/caretPosition.js b/src/static/js/caretPosition.js
index e59fb4be5..32f6d919b 100644
--- a/src/static/js/caretPosition.js
+++ b/src/static/js/caretPosition.js
@@ -1,18 +1,20 @@
+'use strict';
+
 // One rep.line(div) can be broken in more than one line in the browser.
 // This function is useful to get the caret position of the line as
 // is represented by the browser
-exports.getPosition = function () {
+exports.getPosition = () => {
   let rect, line;
-  const editor = $('#innerdocbody')[0];
   const range = getSelectionRange();
-  const isSelectionInsideTheEditor = range && $(range.endContainer).closest('body')[0].id === 'innerdocbody';
+  const isSelectionInsideTheEditor = range &&
+      $(range.endContainer).closest('body')[0].id === 'innerdocbody';
 
   if (isSelectionInsideTheEditor) {
     // when we have the caret in an empty line, e.g. a line with only a <br>,
     // getBoundingClientRect() returns all dimensions value as 0
     const selectionIsInTheBeginningOfLine = range.endOffset > 0;
     if (selectionIsInTheBeginningOfLine) {
-      var clonedRange = createSelectionRange(range);
+      const clonedRange = createSelectionRange(range);
       line = getPositionOfElementOrSelection(clonedRange);
       clonedRange.detach();
     }
@@ -20,7 +22,7 @@ exports.getPosition = function () {
     // when there's a <br> or any element that has no height, we can't get
     // the dimension of the element where the caret is
     if (!rect || rect.height === 0) {
-      var clonedRange = createSelectionRange(range);
+      const clonedRange = createSelectionRange(range);
 
       // as we can't get the element height, we create a text node to get the dimensions
       // on the position
@@ -36,8 +38,8 @@ exports.getPosition = function () {
   return line;
 };
 
-var createSelectionRange = function (range) {
-  clonedRange = range.cloneRange();
+const createSelectionRange = (range) => {
+  const clonedRange = range.cloneRange();
 
   // we set the selection start and end to avoid error when user selects a text bigger than
   // the viewport height and uses the arrow keys to expand the selection. In this particular
@@ -48,7 +50,7 @@ var createSelectionRange = function (range) {
   return clonedRange;
 };
 
-const getPositionOfRepLineAtOffset = function (node, offset) {
+const getPositionOfRepLineAtOffset = (node, offset) => {
   // it is not a text node, so we cannot make a selection
   if (node.tagName === 'BR' || node.tagName === 'EMPTY') {
     return getPositionOfElementOrSelection(node);
@@ -66,7 +68,7 @@ const getPositionOfRepLineAtOffset = function (node, offset) {
   return linePosition;
 };
 
-function getPositionOfElementOrSelection(element) {
+const getPositionOfElementOrSelection = (element) => {
   const rect = element.getBoundingClientRect();
   const linePosition = {
     bottom: rect.bottom,
@@ -74,15 +76,15 @@ function getPositionOfElementOrSelection(element) {
     top: rect.top,
   };
   return linePosition;
-}
+};
 
 // here we have two possibilities:
-// [1] the line before the caret line has the same type, so both of them has the same margin, padding
-// height, etc. So, we can use the caret line to make calculation necessary to know where is the top
-// of the previous line
+// [1] the line before the caret line has the same type, so both of them has the same margin,
+// padding height, etc. So, we can use the caret line to make calculation necessary to know
+// where is the top of the previous line
 // [2] the line before is part of another rep line. It's possible this line has different margins
 // height. So we have to get the exactly position of the line
-exports.getPositionTopOfPreviousBrowserLine = function (caretLinePosition, rep) {
+exports.getPositionTopOfPreviousBrowserLine = (caretLinePosition, rep) => {
   let previousLineTop = caretLinePosition.top - caretLinePosition.height; // [1]
   const isCaretLineFirstBrowserLine = caretLineIsFirstBrowserLine(caretLinePosition.top, rep);
 
@@ -91,13 +93,14 @@ exports.getPositionTopOfPreviousBrowserLine = function (caretLinePosition, rep)
   if (isCaretLineFirstBrowserLine) { // [2]
     const lineBeforeCaretLine = rep.selStart[0] - 1;
     const firstLineVisibleBeforeCaretLine = getPreviousVisibleLine(lineBeforeCaretLine, rep);
-    const linePosition = getDimensionOfLastBrowserLineOfRepLine(firstLineVisibleBeforeCaretLine, rep);
+    const linePosition =
+      getDimensionOfLastBrowserLineOfRepLine(firstLineVisibleBeforeCaretLine, rep);
     previousLineTop = linePosition.top;
   }
   return previousLineTop;
 };
 
-function caretLineIsFirstBrowserLine(caretLineTop, rep) {
+const caretLineIsFirstBrowserLine = (caretLineTop, rep) => {
   const caretRepLine = rep.selStart[0];
   const lineNode = rep.lines.atIndex(caretRepLine).lineNode;
   const firstRootNode = getFirstRootChildNode(lineNode);
@@ -105,37 +108,28 @@ function caretLineIsFirstBrowserLine(caretLineTop, rep) {
   // to get the position of the node we get the position of the first char
   const positionOfFirstRootNode = getPositionOfRepLineAtOffset(firstRootNode, 1);
   return positionOfFirstRootNode.top === caretLineTop;
-}
+};
 
 // find the first root node, usually it is a text node
-function getFirstRootChildNode(node) {
+const getFirstRootChildNode = (node) => {
   if (!node.firstChild) {
     return node;
   } else {
     return getFirstRootChildNode(node.firstChild);
   }
-}
+};
 
-function getPreviousVisibleLine(line, rep) {
-  if (line < 0) {
-    return 0;
-  } else if (isLineVisible(line, rep)) {
-    return line;
-  } else {
-    return getPreviousVisibleLine(line - 1, rep);
-  }
-}
-
-function getDimensionOfLastBrowserLineOfRepLine(line, rep) {
+const getDimensionOfLastBrowserLineOfRepLine = (line, rep) => {
   const lineNode = rep.lines.atIndex(line).lineNode;
   const lastRootChildNode = getLastRootChildNode(lineNode);
 
   // we get the position of the line in the last char of it
-  const lastRootChildNodePosition = getPositionOfRepLineAtOffset(lastRootChildNode.node, lastRootChildNode.length);
+  const lastRootChildNodePosition =
+    getPositionOfRepLineAtOffset(lastRootChildNode.node, lastRootChildNode.length);
   return lastRootChildNodePosition;
-}
+};
 
-function getLastRootChildNode(node) {
+const getLastRootChildNode = (node) => {
   if (!node.lastChild) {
     return {
       node,
@@ -144,39 +138,42 @@ function getLastRootChildNode(node) {
   } else {
     return getLastRootChildNode(node.lastChild);
   }
-}
+};
 
 // here we have two possibilities:
 // [1] The next line is part of the same rep line of the caret line, so we have the same dimensions.
 // So, we can use the caret line to calculate the bottom of the line.
-// [2] the next line is part of another rep line. It's possible this line has different dimensions, so we
-// have to get the exactly dimension of it
-exports.getBottomOfNextBrowserLine = function (caretLinePosition, rep) {
+// [2] the next line is part of another rep line.
+// It's possible this line has different dimensions, so we have to get the exactly dimension of it
+exports.getBottomOfNextBrowserLine = (caretLinePosition, rep) => {
   let nextLineBottom = caretLinePosition.bottom + caretLinePosition.height; // [1]
-  const isCaretLineLastBrowserLine = caretLineIsLastBrowserLineOfRepLine(caretLinePosition.top, rep);
+  const isCaretLineLastBrowserLine =
+    caretLineIsLastBrowserLineOfRepLine(caretLinePosition.top, rep);
 
   // the caret is at the end of a rep line, so we can get the next browser line dimension
   // using the position of the first char of the next rep line
   if (isCaretLineLastBrowserLine) { // [2]
     const nextLineAfterCaretLine = rep.selStart[0] + 1;
     const firstNextLineVisibleAfterCaretLine = getNextVisibleLine(nextLineAfterCaretLine, rep);
-    const linePosition = getDimensionOfFirstBrowserLineOfRepLine(firstNextLineVisibleAfterCaretLine, rep);
+    const linePosition =
+      getDimensionOfFirstBrowserLineOfRepLine(firstNextLineVisibleAfterCaretLine, rep);
     nextLineBottom = linePosition.bottom;
   }
   return nextLineBottom;
 };
 
-function caretLineIsLastBrowserLineOfRepLine(caretLineTop, rep) {
+const caretLineIsLastBrowserLineOfRepLine = (caretLineTop, rep) => {
   const caretRepLine = rep.selStart[0];
   const lineNode = rep.lines.atIndex(caretRepLine).lineNode;
   const lastRootChildNode = getLastRootChildNode(lineNode);
 
   // we take a rep line and get the position of the last char of it
-  const lastRootChildNodePosition = getPositionOfRepLineAtOffset(lastRootChildNode.node, lastRootChildNode.length);
+  const lastRootChildNodePosition =
+    getPositionOfRepLineAtOffset(lastRootChildNode.node, lastRootChildNode.length);
   return lastRootChildNodePosition.top === caretLineTop;
-}
+};
 
-function getPreviousVisibleLine(line, rep) {
+const getPreviousVisibleLine = (line, rep) => {
   const firstLineOfPad = 0;
   if (line <= firstLineOfPad) {
     return firstLineOfPad;
@@ -185,10 +182,12 @@ function getPreviousVisibleLine(line, rep) {
   } else {
     return getPreviousVisibleLine(line - 1, rep);
   }
-}
+};
+
+
 exports.getPreviousVisibleLine = getPreviousVisibleLine;
 
-function getNextVisibleLine(line, rep) {
+const getNextVisibleLine = (line, rep) => {
   const lastLineOfThePad = rep.lines.length() - 1;
   if (line >= lastLineOfThePad) {
     return lastLineOfThePad;
@@ -197,31 +196,28 @@ function getNextVisibleLine(line, rep) {
   } else {
     return getNextVisibleLine(line + 1, rep);
   }
-}
+};
 exports.getNextVisibleLine = getNextVisibleLine;
 
-function isLineVisible(line, rep) {
-  return rep.lines.atIndex(line).lineNode.offsetHeight > 0;
-}
+const isLineVisible = (line, rep) => rep.lines.atIndex(line).lineNode.offsetHeight > 0;
 
-function getDimensionOfFirstBrowserLineOfRepLine(line, rep) {
+const getDimensionOfFirstBrowserLineOfRepLine = (line, rep) => {
   const lineNode = rep.lines.atIndex(line).lineNode;
   const firstRootChildNode = getFirstRootChildNode(lineNode);
 
   // we can get the position of the line, getting the position of the first char of the rep line
   const firstRootChildNodePosition = getPositionOfRepLineAtOffset(firstRootChildNode, 1);
   return firstRootChildNodePosition;
-}
+};
 
-function getSelectionRange() {
-  let selection;
+const getSelectionRange = () => {
   if (!window.getSelection) {
     return;
   }
-  selection = window.getSelection();
+  const selection = window.getSelection();
   if (selection.rangeCount > 0) {
     return selection.getRangeAt(0);
   } else {
     return null;
   }
-}
+};
diff --git a/src/static/js/colorutils.js b/src/static/js/colorutils.js
index 6feba3a75..9688b8e59 100644
--- a/src/static/js/colorutils.js
+++ b/src/static/js/colorutils.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
@@ -26,24 +28,24 @@ const colorutils = {};
 
 // Check that a given value is a css hex color value, e.g.
 // "#ffffff" or "#fff"
-colorutils.isCssHex = function (cssColor) {
-  return /^#([0-9a-f]{3}|[0-9a-f]{6})$/i.test(cssColor);
-};
+colorutils.isCssHex = (cssColor) => /^#([0-9a-f]{3}|[0-9a-f]{6})$/i.test(cssColor);
 
 // "#ffffff" or "#fff" or "ffffff" or "fff" to [1.0, 1.0, 1.0]
-colorutils.css2triple = function (cssColor) {
+colorutils.css2triple = (cssColor) => {
   const sixHex = colorutils.css2sixhex(cssColor);
 
-  function hexToFloat(hh) {
-    return Number(`0x${hh}`) / 255;
-  }
-  return [hexToFloat(sixHex.substr(0, 2)), hexToFloat(sixHex.substr(2, 2)), hexToFloat(sixHex.substr(4, 2))];
+  const hexToFloat = (hh) => Number(`0x${hh}`) / 255;
+  return [
+    hexToFloat(sixHex.substr(0, 2)),
+    hexToFloat(sixHex.substr(2, 2)),
+    hexToFloat(sixHex.substr(4, 2)),
+  ];
 };
 
 // "#ffffff" or "#fff" or "ffffff" or "fff" to "ffffff"
-colorutils.css2sixhex = function (cssColor) {
+colorutils.css2sixhex = (cssColor) => {
   let h = /[0-9a-fA-F]+/.exec(cssColor)[0];
-  if (h.length != 6) {
+  if (h.length !== 6) {
     const a = h.charAt(0);
     const b = h.charAt(1);
     const c = h.charAt(2);
@@ -53,66 +55,54 @@ colorutils.css2sixhex = function (cssColor) {
 };
 
 // [1.0, 1.0, 1.0] -> "#ffffff"
-colorutils.triple2css = function (triple) {
-  function floatToHex(n) {
+colorutils.triple2css = (triple) => {
+  const floatToHex = (n) => {
     const n2 = colorutils.clamp(Math.round(n * 255), 0, 255);
     return (`0${n2.toString(16)}`).slice(-2);
-  }
+  };
   return `#${floatToHex(triple[0])}${floatToHex(triple[1])}${floatToHex(triple[2])}`;
 };
 
 
-colorutils.clamp = function (v, bot, top) {
-  return v < bot ? bot : (v > top ? top : v);
-};
-colorutils.min3 = function (a, b, c) {
-  return (a < b) ? (a < c ? a : c) : (b < c ? b : c);
-};
-colorutils.max3 = function (a, b, c) {
-  return (a > b) ? (a > c ? a : c) : (b > c ? b : c);
-};
-colorutils.colorMin = function (c) {
-  return colorutils.min3(c[0], c[1], c[2]);
-};
-colorutils.colorMax = function (c) {
-  return colorutils.max3(c[0], c[1], c[2]);
-};
-colorutils.scale = function (v, bot, top) {
-  return colorutils.clamp(bot + v * (top - bot), 0, 1);
-};
-colorutils.unscale = function (v, bot, top) {
-  return colorutils.clamp((v - bot) / (top - bot), 0, 1);
-};
+colorutils.clamp = (v, bot, top) => v < bot ? bot : (v > top ? top : v);
+colorutils.min3 = (a, b, c) => (a < b) ? (a < c ? a : c) : (b < c ? b : c);
+colorutils.max3 = (a, b, c) => (a > b) ? (a > c ? a : c) : (b > c ? b : c);
+colorutils.colorMin = (c) => colorutils.min3(c[0], c[1], c[2]);
+colorutils.colorMax = (c) => colorutils.max3(c[0], c[1], c[2]);
+colorutils.scale = (v, bot, top) => colorutils.clamp(bot + v * (top - bot), 0, 1);
+colorutils.unscale = (v, bot, top) => colorutils.clamp((v - bot) / (top - bot), 0, 1);
 
-colorutils.scaleColor = function (c, bot, top) {
-  return [colorutils.scale(c[0], bot, top), colorutils.scale(c[1], bot, top), colorutils.scale(c[2], bot, top)];
-};
+colorutils.scaleColor = (c, bot, top) => [
+  colorutils.scale(c[0], bot, top),
+  colorutils.scale(c[1], bot, top),
+  colorutils.scale(c[2], bot, top),
+];
 
-colorutils.unscaleColor = function (c, bot, top) {
-  return [colorutils.unscale(c[0], bot, top), colorutils.unscale(c[1], bot, top), colorutils.unscale(c[2], bot, top)];
-};
+colorutils.unscaleColor = (c, bot, top) => [
+  colorutils.unscale(c[0], bot, top),
+  colorutils.unscale(c[1], bot, top),
+  colorutils.unscale(c[2], bot, top),
+];
 
-colorutils.luminosity = function (c) {
-  // rule of thumb for RGB brightness; 1.0 is white
-  return c[0] * 0.30 + c[1] * 0.59 + c[2] * 0.11;
-};
+// rule of thumb for RGB brightness; 1.0 is white
+colorutils.luminosity = (c) => c[0] * 0.30 + c[1] * 0.59 + c[2] * 0.11;
 
-colorutils.saturate = function (c) {
+colorutils.saturate = (c) => {
   const min = colorutils.colorMin(c);
   const max = colorutils.colorMax(c);
   if (max - min <= 0) return [1.0, 1.0, 1.0];
   return colorutils.unscaleColor(c, min, max);
 };
 
-colorutils.blend = function (c1, c2, t) {
-  return [colorutils.scale(t, c1[0], c2[0]), colorutils.scale(t, c1[1], c2[1]), colorutils.scale(t, c1[2], c2[2])];
-};
+colorutils.blend = (c1, c2, t) => [
+  colorutils.scale(t, c1[0], c2[0]),
+  colorutils.scale(t, c1[1], c2[1]),
+  colorutils.scale(t, c1[2], c2[2]),
+];
 
-colorutils.invert = function (c) {
-  return [1 - c[0], 1 - c[1], 1 - c[2]];
-};
+colorutils.invert = (c) => [1 - c[0], 1 - c[1], 1 - c[2]];
 
-colorutils.complementary = function (c) {
+colorutils.complementary = (c) => {
   const inv = colorutils.invert(c);
   return [
     (inv[0] >= c[0]) ? Math.min(inv[0] * 1.30, 1) : (c[0] * 0.30),
@@ -121,9 +111,9 @@ colorutils.complementary = function (c) {
   ];
 };
 
-colorutils.textColorFromBackgroundColor = function (bgcolor, skinName) {
-  const white = skinName == 'colibris' ? 'var(--super-light-color)' : '#fff';
-  const black = skinName == 'colibris' ? 'var(--super-dark-color)' : '#222';
+colorutils.textColorFromBackgroundColor = (bgcolor, skinName) => {
+  const white = skinName === 'colibris' ? 'var(--super-light-color)' : '#fff';
+  const black = skinName === 'colibris' ? 'var(--super-dark-color)' : '#222';
 
   return colorutils.luminosity(colorutils.css2triple(bgcolor)) < 0.5 ? white : black;
 };
diff --git a/src/static/js/cssmanager.js b/src/static/js/cssmanager.js
index e0c5e9926..0fcdad403 100644
--- a/src/static/js/cssmanager.js
+++ b/src/static/js/cssmanager.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
@@ -20,14 +22,15 @@
  * limitations under the License.
  */
 
-function makeCSSManager(emptyStylesheetTitle, doc) {
+const makeCSSManager = (emptyStylesheetTitle, doc) => {
   if (doc === true) {
     doc = 'parent';
   } else if (!doc) {
     doc = 'inner';
   }
 
-  function getSheetByTitle(title) {
+  const getSheetByTitle = (title) => {
+    let win;
     if (doc === 'parent') {
       win = window.parent.parent;
     } else if (doc === 'inner') {
@@ -35,46 +38,44 @@ function makeCSSManager(emptyStylesheetTitle, doc) {
     } else if (doc === 'outer') {
       win = window.parent;
     } else {
-      throw 'Unknown dynamic style container';
+      throw new Error('Unknown dynamic style container');
     }
     const allSheets = win.document.styleSheets;
 
     for (let i = 0; i < allSheets.length; i++) {
       const s = allSheets[i];
-      if (s.title == title) {
+      if (s.title === title) {
         return s;
       }
     }
     return null;
-  }
+  };
 
   const browserSheet = getSheetByTitle(emptyStylesheetTitle);
 
-  function browserRules() {
-    return (browserSheet.cssRules || browserSheet.rules);
-  }
+  const browserRules = () => (browserSheet.cssRules || browserSheet.rules);
 
-  function browserDeleteRule(i) {
+  const browserDeleteRule = (i) => {
     if (browserSheet.deleteRule) browserSheet.deleteRule(i);
     else browserSheet.removeRule(i);
-  }
+  };
 
-  function browserInsertRule(i, selector) {
+  const browserInsertRule = (i, selector) => {
     if (browserSheet.insertRule) browserSheet.insertRule(`${selector} {}`, i);
     else browserSheet.addRule(selector, null, i);
-  }
+  };
   const selectorList = [];
 
-  function indexOfSelector(selector) {
+  const indexOfSelector = (selector) => {
     for (let i = 0; i < selectorList.length; i++) {
-      if (selectorList[i] == selector) {
+      if (selectorList[i] === selector) {
         return i;
       }
     }
     return -1;
-  }
+  };
 
-  function selectorStyle(selector) {
+  const selectorStyle = (selector) => {
     let i = indexOfSelector(selector);
     if (i < 0) {
       // add selector
@@ -83,23 +84,21 @@ function makeCSSManager(emptyStylesheetTitle, doc) {
       i = 0;
     }
     return browserRules().item(i).style;
-  }
+  };
 
-  function removeSelectorStyle(selector) {
+  const removeSelectorStyle = (selector) => {
     const i = indexOfSelector(selector);
     if (i >= 0) {
       browserDeleteRule(i);
       selectorList.splice(i, 1);
     }
-  }
+  };
 
   return {
     selectorStyle,
     removeSelectorStyle,
-    info() {
-      return `${selectorList.length}:${browserRules().length}`;
-    },
+    info: () => `${selectorList.length}:${browserRules().length}`,
   };
-}
+};
 
 exports.makeCSSManager = makeCSSManager;
diff --git a/src/static/js/linestylefilter.js b/src/static/js/linestylefilter.js
index e005d1503..919a707f1 100644
--- a/src/static/js/linestylefilter.js
+++ b/src/static/js/linestylefilter.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
@@ -31,7 +33,6 @@
 const Changeset = require('./Changeset');
 const hooks = require('./pluginfw/hooks');
 const linestylefilter = {};
-const _ = require('./underscore');
 const AttributeManager = require('./AttributeManager');
 const padutils = require('./pad_utils').padutils;
 
@@ -45,32 +46,30 @@ linestylefilter.ATTRIB_CLASSES = {
 const lineAttributeMarker = 'lineAttribMarker';
 exports.lineAttributeMarker = lineAttributeMarker;
 
-linestylefilter.getAuthorClassName = function (author) {
-  return `author-${author.replace(/[^a-y0-9]/g, (c) => {
-    if (c == '.') return '-';
-    return `z${c.charCodeAt(0)}z`;
-  })}`;
-};
+linestylefilter.getAuthorClassName = (author) => `author-${author.replace(/[^a-y0-9]/g, (c) => {
+  if (c === '.') return '-';
+  return `z${c.charCodeAt(0)}z`;
+})}`;
 
 // lineLength is without newline; aline includes newline,
 // but may be falsy if lineLength == 0
-linestylefilter.getLineStyleFilter = function (lineLength, aline, textAndClassFunc, apool) {
+linestylefilter.getLineStyleFilter = (lineLength, aline, textAndClassFunc, apool) => {
   // Plugin Hook to add more Attrib Classes
   for (const attribClasses of hooks.callAll('aceAttribClasses', linestylefilter.ATTRIB_CLASSES)) {
     Object.assign(linestylefilter.ATTRIB_CLASSES, attribClasses);
   }
 
-  if (lineLength == 0) return textAndClassFunc;
+  if (lineLength === 0) return textAndClassFunc;
 
   const nextAfterAuthorColors = textAndClassFunc;
 
-  const authorColorFunc = (function () {
+  const authorColorFunc = (() => {
     const lineEnd = lineLength;
     let curIndex = 0;
     let extraClasses;
     let leftInAuthor;
 
-    function attribsToClasses(attribs) {
+    const attribsToClasses = (attribs) => {
       let classes = '';
       let isLineAttribMarker = false;
 top.console.log("attribs", attribs)
@@ -81,14 +80,14 @@ top.console.log("attribs", attribs)
         if (key) {
           const value = apool.getAttribValue(n);
           if (value) {
-            if (!isLineAttribMarker && _.indexOf(AttributeManager.lineAttributes, key) >= 0) {
+            if (!isLineAttribMarker && AttributeManager.lineAttributes.indexOf(key) >= 0) {
               isLineAttribMarker = true;
             }
-            if (key == 'author') {
+            if (key === 'author') {
               classes += ` ${linestylefilter.getAuthorClassName(value)}`;
-            } else if (key == 'list') {
+            } else if (key === 'list') {
               classes += ` list:${value}`;
-            } else if (key == 'start') {
+            } else if (key === 'start') {
               // Needed to introduce the correct Ordered list item start number on import
               classes += ` start:${value}`;
             } else if (linestylefilter.ATTRIB_CLASSES[key]) {
@@ -106,37 +105,38 @@ top.console.log("attribs", attribs)
 
       if (isLineAttribMarker) classes += ` ${lineAttributeMarker}`;
       return classes.substring(1);
-    }
+    };
 
     const attributionIter = Changeset.opIterator(aline);
     let nextOp, nextOpClasses;
 
-    function goNextOp() {
+    const goNextOp = () => {
       nextOp = attributionIter.next();
       nextOpClasses = (nextOp.opcode && attribsToClasses(nextOp.attribs));
-    }
+    };
     goNextOp();
 
-    function nextClasses() {
+    const nextClasses = () => {
       if (curIndex < lineEnd) {
         extraClasses = nextOpClasses;
         leftInAuthor = nextOp.chars;
         goNextOp();
-        while (nextOp.opcode && nextOpClasses == extraClasses) {
+        while (nextOp.opcode && nextOpClasses === extraClasses) {
           leftInAuthor += nextOp.chars;
           goNextOp();
         }
       }
-    }
+    };
     nextClasses();
 
-    return function (txt, cls) {
+    return (txt, cls) => {
       const disableAuthColorForThisLine = hooks.callAll('disableAuthorColorsForThisLine', {
         linestylefilter,
         text: txt,
         class: cls,
       }, ' ', ' ', '');
-      const disableAuthors = (disableAuthColorForThisLine == null || disableAuthColorForThisLine.length == 0) ? false : disableAuthColorForThisLine[0];
+      const disableAuthors = (disableAuthColorForThisLine == null ||
+        disableAuthColorForThisLine.length === 0) ? false : disableAuthColorForThisLine[0];
       while (txt.length > 0) {
         if (leftInAuthor <= 0 || disableAuthors) {
           // prevent infinite loop if something funny's going on
@@ -151,7 +151,7 @@ top.console.log("attribs", attribs)
         nextAfterAuthorColors(curTxt, (cls && `${cls} `) + extraClasses);
         curIndex += spanSize;
         leftInAuthor -= spanSize;
-        if (leftInAuthor == 0) {
+        if (leftInAuthor === 0) {
           nextClasses();
         }
       }
@@ -160,7 +160,7 @@ top.console.log("attribs", attribs)
   return authorColorFunc;
 };
 
-linestylefilter.getAtSignSplitterFilter = function (lineText, textAndClassFunc) {
+linestylefilter.getAtSignSplitterFilter = (lineText, textAndClassFunc) => {
   const at = /@/g;
   at.lastIndex = 0;
   let splitPoints = null;
@@ -177,66 +177,66 @@ linestylefilter.getAtSignSplitterFilter = function (lineText, textAndClassFunc)
   return linestylefilter.textAndClassFuncSplitter(textAndClassFunc, splitPoints);
 };
 
-linestylefilter.getRegexpFilter = function (regExp, tag) {
-  return function (lineText, textAndClassFunc) {
-    regExp.lastIndex = 0;
-    let regExpMatchs = null;
-    let splitPoints = null;
-    let execResult;
-    while ((execResult = regExp.exec(lineText))) {
-      if (!regExpMatchs) {
-        regExpMatchs = [];
-        splitPoints = [];
-      }
-      const startIndex = execResult.index;
-      const regExpMatch = execResult[0];
-      regExpMatchs.push([startIndex, regExpMatch]);
-      splitPoints.push(startIndex, startIndex + regExpMatch.length);
+linestylefilter.getRegexpFilter = (regExp, tag) => (lineText, textAndClassFunc) => {
+  regExp.lastIndex = 0;
+  let regExpMatchs = null;
+  let splitPoints = null;
+  let execResult;
+  while ((execResult = regExp.exec(lineText))) {
+    if (!regExpMatchs) {
+      regExpMatchs = [];
+      splitPoints = [];
     }
+    const startIndex = execResult.index;
+    const regExpMatch = execResult[0];
+    regExpMatchs.push([startIndex, regExpMatch]);
+    splitPoints.push(startIndex, startIndex + regExpMatch.length);
+  }
 
-    if (!regExpMatchs) return textAndClassFunc;
+  if (!regExpMatchs) return textAndClassFunc;
 
-    function regExpMatchForIndex(idx) {
-      for (let k = 0; k < regExpMatchs.length; k++) {
-        const u = regExpMatchs[k];
-        if (idx >= u[0] && idx < u[0] + u[1].length) {
-          return u[1];
-        }
+  const regExpMatchForIndex = (idx) => {
+    for (let k = 0; k < regExpMatchs.length; k++) {
+      const u = regExpMatchs[k];
+      if (idx >= u[0] && idx < u[0] + u[1].length) {
+        return u[1];
       }
-      return false;
     }
-
-    const handleRegExpMatchsAfterSplit = (function () {
-      let curIndex = 0;
-      return function (txt, cls) {
-        const txtlen = txt.length;
-        let newCls = cls;
-        const regExpMatch = regExpMatchForIndex(curIndex);
-        if (regExpMatch) {
-          newCls += ` ${tag}:${regExpMatch}`;
-        }
-        textAndClassFunc(txt, newCls);
-        curIndex += txtlen;
-      };
-    })();
-
-    return linestylefilter.textAndClassFuncSplitter(handleRegExpMatchsAfterSplit, splitPoints);
+    return false;
   };
+
+  const handleRegExpMatchsAfterSplit = (() => {
+    let curIndex = 0;
+    return (txt, cls) => {
+      const txtlen = txt.length;
+      let newCls = cls;
+      const regExpMatch = regExpMatchForIndex(curIndex);
+      if (regExpMatch) {
+        newCls += ` ${tag}:${regExpMatch}`;
+      }
+      textAndClassFunc(txt, newCls);
+      curIndex += txtlen;
+    };
+  })();
+
+  return linestylefilter.textAndClassFuncSplitter(handleRegExpMatchsAfterSplit, splitPoints);
 };
 
 
 linestylefilter.getURLFilter = linestylefilter.getRegexpFilter(padutils.urlRegex, 'url');
 
-linestylefilter.textAndClassFuncSplitter = function (func, splitPointsOpt) {
+linestylefilter.textAndClassFuncSplitter = (func, splitPointsOpt) => {
   let nextPointIndex = 0;
   let idx = 0;
 
   // don't split at 0
-  while (splitPointsOpt && nextPointIndex < splitPointsOpt.length && splitPointsOpt[nextPointIndex] == 0) {
+  while (splitPointsOpt &&
+      nextPointIndex < splitPointsOpt.length &&
+      splitPointsOpt[nextPointIndex] === 0) {
     nextPointIndex++;
   }
 
-  function spanHandler(txt, cls) {
+  const spanHandler = (txt, cls) => {
     if ((!splitPointsOpt) || nextPointIndex >= splitPointsOpt.length) {
       func(txt, cls);
       idx += txt.length;
@@ -247,7 +247,7 @@ linestylefilter.textAndClassFuncSplitter = function (func, splitPointsOpt) {
       if (pointLocInSpan >= txtlen) {
         func(txt, cls);
         idx += txt.length;
-        if (pointLocInSpan == txtlen) {
+        if (pointLocInSpan === txtlen) {
           nextPointIndex++;
         }
       } else {
@@ -260,18 +260,18 @@ linestylefilter.textAndClassFuncSplitter = function (func, splitPointsOpt) {
         spanHandler(txt.substring(pointLocInSpan), cls);
       }
     }
-  }
+  };
   return spanHandler;
 };
 
-linestylefilter.getFilterStack = function (lineText, textAndClassFunc, abrowser) {
+linestylefilter.getFilterStack = (lineText, textAndClassFunc, abrowser) => {
   let func = linestylefilter.getURLFilter(lineText, textAndClassFunc);
 
   const hookFilters = hooks.callAll('aceGetFilterStack', {
     linestylefilter,
     browser: abrowser,
   });
-  _.map(hookFilters, (hookFilter) => {
+  hookFilters.map((hookFilter) => {
     func = hookFilter(lineText, func);
   });
 
@@ -279,16 +279,16 @@ linestylefilter.getFilterStack = function (lineText, textAndClassFunc, abrowser)
 };
 
 // domLineObj is like that returned by domline.createDomLine
-linestylefilter.populateDomLine = function (textLine, aline, apool, domLineObj) {
+linestylefilter.populateDomLine = (textLine, aline, apool, domLineObj) => {
   // remove final newline from text if any
   let text = textLine;
-  if (text.slice(-1) == '\n') {
+  if (text.slice(-1) === '\n') {
     text = text.substring(0, text.length - 1);
   }
 
-  function textAndClassFunc(tokenText, tokenClass) {
+  const textAndClassFunc = (tokenText, tokenClass) => {
     domLineObj.appendSpan(tokenText, tokenClass);
-  }
+  };
 
   let func = linestylefilter.getFilterStack(text, textAndClassFunc);
   func = linestylefilter.getLineStyleFilter(text.length, aline, func, apool);
diff --git a/src/static/js/rjquery.js b/src/static/js/rjquery.js
index f055d56f8..d729a25ba 100644
--- a/src/static/js/rjquery.js
+++ b/src/static/js/rjquery.js
@@ -1,4 +1,5 @@
-// Proviedes a require'able version of jQuery without leaking $ and jQuery;
+'use strict';
+// Provides a require'able version of jQuery without leaking $ and jQuery;
 window.$ = require('./jquery');
 const jq = window.$.noConflict(true);
 exports.jQuery = exports.$ = jq;