JSFiddle - React, Tailwind, and code Playground

JavaScript

var myobject = {"MethodName":"ID,11|1|Item1,22|2|Item2,33|3|Item3"};
var itemlist = [];
var method;
var ID;

for (key in myobject) { 
    method = key;
    break;
}

itemlist = myobject[method].split(',');
ID = itemlist.shift();

alert("method=" + method + "\nID=" + ID + "\nitemlist=" + itemlist);