[
  {
    "operation": "modify-default-beta",
    "spec": {
      "y": "=join(',',@(1,x))",
      "z": "=join(' ',@(1,x))",
      "small_toUpper": "=toUpper(@(1,small))",
      "BIG_toLower": "=toLower(@(1,BIG))",
      "people": {
        "*": {
          "fullName": "=concat(@(1,firstName),' ',@(1,lastName))",
          "address?": {
            "state": "Texas"
          }
        }
      }
    }
  }
]