diff --git a/eslint.config.js b/eslint.config.js
index ed703ea71..8b4807bc5 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -109,6 +109,7 @@ export default tseslint.config(
       '@typescript-eslint/no-unsafe-member-access': 'off',
       '@typescript-eslint/no-unsafe-return': 'off',
       '@typescript-eslint/only-throw-error': 'warn',
+      '@typescript-eslint/prefer-nullish-coalescing': 'warn',
       '@typescript-eslint/prefer-promise-reject-errors': 'warn',
       // END
       'json/*': ['error', 'allowComments'],
diff --git a/packages/mermaid-layout-elk/src/render.ts b/packages/mermaid-layout-elk/src/render.ts
index ead157a04..79bd9bbf0 100644
--- a/packages/mermaid-layout-elk/src/render.ts
+++ b/packages/mermaid-layout-elk/src/render.ts
@@ -144,7 +144,7 @@ const drawNodes = (relX, relY, nodeArray, svg, subgraphsEl, depth) => {
     }
   });
   nodeArray.forEach(function (node) {
-    if (node && node.isGroup) {
+    if (node?.isGroup) {
       drawNodes(relX + node.x, relY + node.y, node.children, svg, subgraphsEl, depth + 1);
     }
   });
diff --git a/packages/mermaid/src/rendering-util/createText.ts b/packages/mermaid/src/rendering-util/createText.ts
index 6ee2bf921..d3428f019 100644
--- a/packages/mermaid/src/rendering-util/createText.ts
+++ b/packages/mermaid/src/rendering-util/createText.ts
@@ -231,10 +231,10 @@ export const createText = async (
       structuredText,
       text ? addSvgBackground : false
     );
-    if (style.match('stroke:')) style = style.replace('stroke:', 'lineColor:');
+    if (/stroke:/.exec(style)) {style = style.replace('stroke:', 'lineColor:');}
     select(svgLabel)
       .select('text')
-      .attr('style', style.replace(/color\:/g, 'fill:'));
+      .attr('style', style.replace(/color:/g, 'fill:'));
     // svgLabel.setAttribute('style', style);
     return svgLabel;
   }
diff --git a/packages/mermaid/src/rendering-util/layout-algorithms/dagre/index.js b/packages/mermaid/src/rendering-util/layout-algorithms/dagre/index.js
index c5855849b..80ab33eb3 100644
--- a/packages/mermaid/src/rendering-util/layout-algorithms/dagre/index.js
+++ b/packages/mermaid/src/rendering-util/layout-algorithms/dagre/index.js
@@ -69,7 +69,7 @@ const recursiveRender = async (_elem, graph, diagramType, id, parentCluster, sit
         }
       }
       log.info('(Insert) Node XXX' + v + ': ' + JSON.stringify(graph.node(v)));
-      if (node && node.clusterNode) {
+      if (node?.clusterNode) {
         // const children = graph.children(v);
         log.info('Cluster identified XBX', v, node.width, graph.node(v));
 
@@ -217,7 +217,7 @@ const recursiveRender = async (_elem, graph, diagramType, id, parentCluster, sit
         ' height: ',
         node.height
       );
-      if (node && node.clusterNode) {
+      if (node?.clusterNode) {
         const parentId = graph.parent(v);
         // Adjust for padding when on root level
         node.y += subGraphTitleTotalMargin;
diff --git a/packages/mermaid/src/rendering-util/layout-algorithms/dagre/mermaid-graphlib.js b/packages/mermaid/src/rendering-util/layout-algorithms/dagre/mermaid-graphlib.js
index ac834b8f5..883fbdc89 100644
--- a/packages/mermaid/src/rendering-util/layout-algorithms/dagre/mermaid-graphlib.js
+++ b/packages/mermaid/src/rendering-util/layout-algorithms/dagre/mermaid-graphlib.js
@@ -437,7 +437,7 @@ export const extractor = (graph, depth) => {
 
       const graphSettings = graph.graph();
       let dir = graphSettings.rankdir === 'TB' ? 'LR' : 'TB';
-      if (clusterDb[node] && clusterDb[node].clusterData && clusterDb[node].clusterData.dir) {
+      if (clusterDb[node]?.clusterData?.dir) {
         dir = clusterDb[node].clusterData.dir;
         log.warn('Fixing dir', clusterDb[node].clusterData.dir, dir);
       }
diff --git a/packages/mermaid/src/rendering-util/rendering-elements/clusters.js b/packages/mermaid/src/rendering-util/rendering-elements/clusters.js
index 6b06eb139..aa273c380 100644
--- a/packages/mermaid/src/rendering-util/rendering-elements/clusters.js
+++ b/packages/mermaid/src/rendering-util/rendering-elements/clusters.js
@@ -224,7 +224,6 @@ const roundedWithTitle = async (parent, node) => {
   const y = node.y - height / 2;
   node.width = width;
   const innerY = node.y - node.height / 2 - halfPadding + bbox.height + 2;
-  const look = siteConfig.look;
 
   // add the rect
   let rect;
@@ -290,12 +289,11 @@ const roundedWithTitle = async (parent, node) => {
 
   return { cluster: shapeSvg, labelBBox: bbox };
 };
-const divider = async (parent, node) => {
+const divider = (parent, node) => {
   const siteConfig = getConfig();
 
   const { themeVariables, handdrawnSeed } = siteConfig;
-  const { altBackground, compositeBackground, compositeTitleBackground, nodeBorder } =
-    themeVariables;
+  const { compositeTitleBackground, nodeBorder } = themeVariables;
 
   // Add outer g element
   const shapeSvg = parent
@@ -307,11 +305,7 @@ const divider = async (parent, node) => {
   // add the rect
   const outerRectG = shapeSvg.insert('g', ':first-child');
 
-  // Create the label and insert it after the rect
-  let innerRect = shapeSvg.append('rect');
-
   const padding = 0 * node.padding;
-  const halfPadding = padding / 2;
 
   const width = node.width + padding;
 
@@ -322,12 +316,10 @@ const divider = async (parent, node) => {
   const x = node.x - width / 2;
   const y = node.y - height / 2;
   node.width = width;
-  const look = siteConfig.look;
 
   // add the rect
   let rect;
   if (node.look === 'handdrawn') {
-    const isAlt = node.cssClasses.includes('statediagram-cluster-alt');
     const rc = rough.svg(shapeSvg);
     const roughOuterNode =
       node.rx || node.ry
@@ -368,53 +360,6 @@ const divider = async (parent, node) => {
   return { cluster: shapeSvg, labelBBox: {} };
 };
 
-const dividerOrg = (parent, node) => {
-  console.log('Divider node IPI', node);
-  const { handdrawnSeed } = getConfig();
-  // Add outer g element
-  const shapeSvg = parent.insert('g').attr('class', node.cssClasses).attr('id', node.id);
-
-  // add the rect
-  let rect;
-
-  const padding = 0 * node.padding;
-  const halfPadding = padding / 2;
-
-  const x = node.x - node.width / 2 - node.padding;
-  const y = node.y - node.height / 2 + node.padding;
-  const width = node.width + padding;
-  const height = node.height + padding;
-  if (node.look === 'handdrawn') {
-    const rc = rough.svg(shapeSvg);
-    const roughNode = rc.rectangle(x, y, width, height, {
-      fill: 'lightgrey',
-      roughness: 0.5,
-      strokeLineDash: [5],
-      seed: handdrawnSeed,
-    });
-
-    rect = shapeSvg.insert(() => roughNode);
-  } else {
-    rect = shapeSvg.insert('rect', ':first-child');
-    // center the rect around its coordinate
-    rect
-      .attr('class', 'divider')
-      .attr('x', x)
-      .attr('y', y)
-      .attr('width', width)
-      .attr('height', height);
-  }
-  const rectBox = rect.node().getBBox();
-  node.width = rectBox.width;
-  node.height = rectBox.height - node.padding;
-  node.diff = 0; //-node.padding / 2;
-  node.offsetY = 0;
-  node.intersect = function (point) {
-    return intersectRect(node, point);
-  };
-
-  return { cluster: shapeSvg, labelBBox: { width: 0, height: 0 } };
-};
 const squareRect = rect;
 const shapes = {
   rect,