diff --git a/common.js b/common.js
index <HASH>..<HASH> 100644
--- a/common.js
+++ b/common.js
@@ -188,9 +188,11 @@ function schemaToArray(schema,offset,options,data) {
     let blockDepth = 0;
     let container = [];
     let block = { title: '', rows: [] };
-    if (schema.description) block.title = schema.description;
-    if (!block.title && schema.title) block.title = schema.title;
-    if (schema.externalDocs) block.externalDocs = schema.externalDocs;
+    if (schema) {
+        if (schema.description) block.title = schema.description;
+        if (!block.title && schema.title) block.title = schema.title;
+        if (schema.externalDocs) block.externalDocs = schema.externalDocs;
+    }
     container.push(block);
     let wsState = wsGetState();
     wsState.combine = true;
Harden prev commit against undefined schemas