diff --git a/packages/mermaid/src/dagre-wrapper/clusters.js b/packages/mermaid/src/dagre-wrapper/clusters.js
index 2c7746876..8686aa9aa 100644
--- a/packages/mermaid/src/dagre-wrapper/clusters.js
+++ b/packages/mermaid/src/dagre-wrapper/clusters.js
@@ -238,7 +238,7 @@ let clusterElems = {};
 
 export const insertCluster = (elem, node) => {
   log.trace('Inserting cluster');
-  const shape = node.shape || 'rect';
+  const shape = node.shape ?? 'rect';
   clusterElems[node.id] = shapes[shape](elem, node);
 };
 export const getClusterTitleWidth = (elem, node) => {