I found that tile map editor could export json string ( At menu, "File" -> "Export As" -> "Json files" )
, so that I try to support that.
This is my teat capx
But I am not sure I had covered all cases. Please help me to test it. (I forgot how to create object layer, so I might be miss that.)
The older method to get json string is using tmx2json tool
I made before. I recommend user use the official exporting one.
Your input string is XML format, not json.