diff --git a/repository/TiddlyWiki/TiddlyWiki.class.st b/repository/TiddlyWiki/TiddlyWiki.class.st
index e37435c..5baf186 100644
--- a/repository/TiddlyWiki/TiddlyWiki.class.st
+++ b/repository/TiddlyWiki/TiddlyWiki.class.st
@@ -353,7 +353,7 @@ TiddlyWiki >> jsonFile: aFileLocator [
 { #category : #accessing }
 TiddlyWiki >> jsonSubtiddlers: subtiddlersCollection [
 	| subtiddlersDict |
-	subtiddlersDict := subtiddlersCollection collect: [:tiddler | tiddler asDictionary ].
+	subtiddlersDict := subtiddlersCollection asArray collect: [:tiddler | tiddler asDictionary ].
 	^ STONJSON toStringPretty: subtiddlersDict
 ]