How to define USERDATA in JSON format

I am using very strongly USERDATA in my project and I would like to move to JSON as an input data format. Can you please tell me whether it is possible to define USERDATA in json.

thanks!
Choesang

The userdata example:

{id:0, item:[{id:1,text:“item 1”,userdata:[{name:“ud1”, content:"your data "},{name:“ud2”, content:“other data here”}]},{id:2, text:“item 2”},{id:3,text:“item 3”}]}

var data1 = tree.getUserData(1,“ud1”);
var data2 = tree.getUserData(1,“ud2”);

thanks alexandra!