Track subgraph open history for breadcrumbs

src/utils/typeGuardUtil.ts

@@ -21,3 +21,9 @@ export const isAbortError = (
 export const isSubgraph = (
   item: LGraph | Subgraph | undefined | null
 ): item is Subgraph => item?.isRootGraph === false
+
+/**
+ * Check if an item is non-nullish.
+ */
+export const isNonNullish = <T>(item: T | undefined | null): item is T =>
+  item != null