How can I parse in Javascript a Bonita Variable?

Hello,

I have on my process a List Variable. It's a List<List<Map<String,Object>>.

I need to explode it in my UIDesigner.

I call this REST API

../API/bpm/caseVariable/{{$item.rootCaseId}}/detailResult

and I get that:

{"case_id":"6004","name":"detailResult","description":"","type":"java.util.List","value":"[[{name=ReviewManager, percent=43},{name=ReviewDirector, percent=55}], [{name=Review Team, percent=12}]]"}

How can I parse this String to have a Json Variable?

Using in my controller "formatedValue= JSON.parse( $data.resultDetail )" cause a "vendor.min.js:105 Error evaluating < formControler > data:  Unexpected token n in JSON at position 3"

because the result is not correctly formatted.

I know that if I use the REST API CONTEXT, I will get the correct data, but is a solution exist in the JavaScript world to transform this String into a parse-able JSON?

Best,