promblem apex 23.1.0

[lucbind]

I can't able to run on apex 23.1.0

I imported the plugin
I create an item json_viewr type (P6_PRETTY)
I use button to copy value from an item(P6_JSON) to the new item (P6_PRETTY) by js. apex.item( "P6_JSON" ).getValue()
but nothing happend

[lucbind]

taxError: Unexpected end of JSON input
at Function.parse [as parseJSON] ()
at new JsonViewer (json-viewer.js:22:22)
at HTMLDivElement. (json-viewer.js:17:13)
at Function.each (desktop_all.min.js?v=23.1.0:2:3003)
at S.fn.init.each (desktop_all.min.js?v=23.1.0:2:1481)
at $.fn.jsonview (json-viewer.js:6:21)
at cancellare?session=115452955960699:293:60
at HTMLDocument. (cancellare?session=115452955960699:293:75)
at e.init (desktop_all.min.js?v=23.1.0:20:5718)
at HTMLDocument. (cancellare?session=115452955960699:290:11)
e