diff --git a/core/events/events_var_base.js b/core/events/events_var_base.js
index 202218269..3effcbce7 100644
--- a/core/events/events_var_base.js
+++ b/core/events/events_var_base.js
@@ -49,7 +49,7 @@ Blockly.utils.object.inherits(Blockly.Events.VarBase, Blockly.Events.Abstract);
  * @return {!Object} JSON representation.
  */
 Blockly.Events.VarBase.prototype.toJson = function() {
-  var json = Blockly.Events.VarBase.superClass_.toJson.call(this);
+  const json = Blockly.Events.VarBase.superClass_.toJson.call(this);
   json['varId'] = this.varId;
   return json;
 };
diff --git a/core/events/events_var_create.js b/core/events/events_var_create.js
index a228a1b92..69811feeb 100644
--- a/core/events/events_var_create.js
+++ b/core/events/events_var_create.js
@@ -49,7 +49,7 @@ Blockly.Events.VarCreate.prototype.type = Blockly.Events.VAR_CREATE;
  * @return {!Object} JSON representation.
  */
 Blockly.Events.VarCreate.prototype.toJson = function() {
-  var json = Blockly.Events.VarCreate.superClass_.toJson.call(this);
+  const json = Blockly.Events.VarCreate.superClass_.toJson.call(this);
   json['varType'] = this.varType;
   json['varName'] = this.varName;
   return json;
@@ -70,7 +70,7 @@ Blockly.Events.VarCreate.prototype.fromJson = function(json) {
  * @param {boolean} forward True if run forward, false if run backward (undo).
  */
 Blockly.Events.VarCreate.prototype.run = function(forward) {
-  var workspace = this.getEventWorkspace_();
+  const workspace = this.getEventWorkspace_();
   if (forward) {
     workspace.createVariable(this.varName, this.varType, this.varId);
   } else {
diff --git a/core/events/events_var_delete.js b/core/events/events_var_delete.js
index 87a57b1b9..284e499b3 100644
--- a/core/events/events_var_delete.js
+++ b/core/events/events_var_delete.js
@@ -49,7 +49,7 @@ Blockly.Events.VarDelete.prototype.type = Blockly.Events.VAR_DELETE;
  * @return {!Object} JSON representation.
  */
 Blockly.Events.VarDelete.prototype.toJson = function() {
-  var json = Blockly.Events.VarDelete.superClass_.toJson.call(this);
+  const json = Blockly.Events.VarDelete.superClass_.toJson.call(this);
   json['varType'] = this.varType;
   json['varName'] = this.varName;
   return json;
@@ -70,7 +70,7 @@ Blockly.Events.VarDelete.prototype.fromJson = function(json) {
  * @param {boolean} forward True if run forward, false if run backward (undo).
  */
 Blockly.Events.VarDelete.prototype.run = function(forward) {
-  var workspace = this.getEventWorkspace_();
+  const workspace = this.getEventWorkspace_();
   if (forward) {
     workspace.deleteVariableById(this.varId);
   } else {
diff --git a/core/events/events_var_rename.js b/core/events/events_var_rename.js
index 60368e0af..90329f0be 100644
--- a/core/events/events_var_rename.js
+++ b/core/events/events_var_rename.js
@@ -50,7 +50,7 @@ Blockly.Events.VarRename.prototype.type = Blockly.Events.VAR_RENAME;
  * @return {!Object} JSON representation.
  */
 Blockly.Events.VarRename.prototype.toJson = function() {
-  var json = Blockly.Events.VarRename.superClass_.toJson.call(this);
+  const json = Blockly.Events.VarRename.superClass_.toJson.call(this);
   json['oldName'] = this.oldName;
   json['newName'] = this.newName;
   return json;
@@ -71,7 +71,7 @@ Blockly.Events.VarRename.prototype.fromJson = function(json) {
  * @param {boolean} forward True if run forward, false if run backward (undo).
  */
 Blockly.Events.VarRename.prototype.run = function(forward) {
-  var workspace = this.getEventWorkspace_();
+  const workspace = this.getEventWorkspace_();
   if (forward) {
     workspace.renameVariableById(this.varId, this.newName);
   } else {