diff --git a/tools/parse-processor.mjs b/tools/parse-processor.mjs
index f78c4c0261..debde68665 100644
--- a/tools/parse-processor.mjs
+++ b/tools/parse-processor.mjs
@@ -40,7 +40,7 @@ function BYTES(bytes, total) {
     unitIndex++;
   }
   let result = formatNumber(value).padStart(10) + ' ' + units[unitIndex];
-  if (total !== void 0 && total != 0) {
+  if (total !== undefined && total != 0) {
     result += PERCENT(bytes, total).padStart(5);
   }
   return result;
@@ -161,7 +161,7 @@ class CompilationUnit {
 class Script extends CompilationUnit {
   constructor(id) {
     super();
-    if (id === void 0 || id <= 0) {
+    if (id === undefined || id <= 0) {
       throw new Error(`Invalid id=${id} for script`);
     }
     this.file = '';
@@ -214,7 +214,7 @@ class Script extends CompilationUnit {
   addMissingFunktions(list) {
     if (this.finalized) throw 'script is finalized!';
     list.forEach(fn => {
-      if (this.funktions[fn.start] === void 0) {
+      if (this.funktions[fn.start] === undefined) {
         this.addFunktion(fn);
       }
     });
@@ -222,8 +222,8 @@ class Script extends CompilationUnit {
 
   addFunktion(fn) {
     if (this.finalized) throw 'script is finalized!';
-    if (fn.start === void 0) throw "Funktion has no start position";
-    if (this.funktions[fn.start] !== void 0) {
+    if (fn.start === undefined) throw "Funktion has no start position";
+    if (this.funktions[fn.start] !== undefined) {
       fn.print();
       throw "adding same function twice to script";
     }
@@ -441,7 +441,7 @@ class Script extends CompilationUnit {
       for (let i = 1; i < metricProperties.length; i += kMetricIncrement) {
         let timestampPropertyName = metricProperties[i];
         let timestamp = funktionOrScript[timestampPropertyName];
-        if (timestamp === void 0) continue;
+        if (timestamp === undefined) continue;
         if (timestamp < start || end < timestamp) continue;
         timestamp -= start;
         let index = Math.floor(timestamp / delta);
@@ -906,7 +906,7 @@ export class ParseProcessor extends LogReader {
     }
     let script = this.lookupScript(scriptId);
     let funktion = script.getFunktionAtStartPosition(startPosition);
-    if (funktion === void 0) {
+    if (funktion === undefined) {
       funktion = new Funktion(functionName, startPosition, endPosition, script);
     }
     return funktion;
diff --git a/tools/system-analyzer/helper.mjs b/tools/system-analyzer/helper.mjs
index bbf7a1241d..49202a7cc6 100644
--- a/tools/system-analyzer/helper.mjs
+++ b/tools/system-analyzer/helper.mjs
@@ -24,4 +24,4 @@ export function formatSeconds(millis) {
 
 export function delay(time) {
   return new Promise(resolver => setTimeout(resolver, time));
-}
\ No newline at end of file
+}
diff --git a/tools/system-analyzer/log/log.mjs b/tools/system-analyzer/log/log.mjs
index 69195d7853..c965124b39 100644
--- a/tools/system-analyzer/log/log.mjs
+++ b/tools/system-analyzer/log/log.mjs
@@ -20,4 +20,4 @@ export class LogEntry {
   static get allTypes() {
     throw new Error('Not implemented.');
   }
-}
\ No newline at end of file
+}
diff --git a/tools/system-analyzer/log/map.mjs b/tools/system-analyzer/log/map.mjs
index 46fd4c385c..e376844ca9 100644
--- a/tools/system-analyzer/log/map.mjs
+++ b/tools/system-analyzer/log/map.mjs
@@ -34,7 +34,7 @@ define(Array.prototype, 'last', function() {
 // Map Log Events
 
 class MapLogEntry extends LogEntry {
-  edge = void 0;
+  edge = undefined;
   children = [];
   depth = 0;
   _isDeprecated = false;
@@ -80,8 +80,7 @@ class MapLogEntry extends LogEntry {
   }
 
   parent() {
-    if (this.edge === void 0) return void 0;
-    return this.edge.from;
+    return this.edge?.from;
   }
 
   isDeprecated() {
@@ -93,7 +92,7 @@ class MapLogEntry extends LogEntry {
   }
 
   isRoot() {
-    return this.edge === void 0 || this.edge.from === void 0;
+    return this.edge === undefined || this.edge.from === undefined;
   }
 
   contains(map) {
@@ -136,11 +135,11 @@ class MapLogEntry extends LogEntry {
   }
 
   get type() {
-    return this.edge === void 0 ? 'new' : this.edge.type;
+    return this.edge === undefined ? 'new' : this.edge.type;
   }
 
   isBootstrapped() {
-    return this.edge === void 0;
+    return this.edge === undefined;
   }
 
   getParents() {
diff --git a/tools/system-analyzer/view/events.mjs b/tools/system-analyzer/view/events.mjs
index 2142d4db2b..db5b72e696 100644
--- a/tools/system-analyzer/view/events.mjs
+++ b/tools/system-analyzer/view/events.mjs
@@ -69,4 +69,4 @@ export class ToolTipEvent extends CustomEvent {
   get positionOrTargetNode() {
     return this._positionOrTargetNode;
   }
-}
\ No newline at end of file
+}
diff --git a/tools/system-analyzer/view/map-panel/map-transitions.mjs b/tools/system-analyzer/view/map-panel/map-transitions.mjs
index 2b19314697..e983ff1805 100644
--- a/tools/system-analyzer/view/map-panel/map-transitions.mjs
+++ b/tools/system-analyzer/view/map-panel/map-transitions.mjs
@@ -87,7 +87,7 @@ DOM.defineCustomElement(
       }
 
       _addMapAndParentTransitions(map) {
-        if (map === void 0) return;
+        if (map === undefined) return;
         if (this._displayedMapsInTree.has(map)) return;
         this._displayedMapsInTree.add(map);
         this.currentNode = this.transitionView;
@@ -191,7 +191,7 @@ DOM.defineCustomElement(
           // Add subtransitions except the one that's already shown.
           let visibleTransitionMap = subtransitionNodes.length == 1 ?
               transitionsNode.querySelector('.map').map :
-              void 0;
+              undefined;
           map.children.forEach((edge) => {
             if (edge.to != visibleTransitionMap) {
               this.currentNode = transitionsNode;
diff --git a/tools/system-analyzer/view/source-panel.mjs b/tools/system-analyzer/view/source-panel.mjs
index b4b6aabcad..c2fdac616a 100644
--- a/tools/system-analyzer/view/source-panel.mjs
+++ b/tools/system-analyzer/view/source-panel.mjs
@@ -249,4 +249,4 @@ class LineBuilder {
     marker.onmouseover = this._mouseoverHandler;
     return marker;
   }
-}
\ No newline at end of file
+}