JSFiddle - React, Tailwind, and code Playground

by tivie

HTML

<script id="myJson" type="application/json">
{
   "stuff":[
      {
         "State_Code":"01",
         "County_Code":"000",
         "State_Abbrv":"AL",
         "County_Name":"ALABAMA",
         "DATA":"12345"
      },
      {
         "State_Code":"01",
         "County_Code":"001",
         "State_Abbrv":"AL",
         "County_Name":"AUTAUGA COUNTY",
         "DATA":"123"
      },
      {
         "State_Code":"01",
         "County_Code":"003",
         "State_Abbrv":"AL",
         "County_Name":"BALDWIN COUNTY",
         "DATA":"321"
      },
      {
         "State_Code":"02",
         "County_Code":"000",
         "State_Abbrv":"AK",
         "County_Name":"ALASKA",
         "DATA":"98765"
      },
      {
         "State_Code":"02",
         "County_Code":"013",
         "State_Abbrv":"AK",
         "County_Name":"ALEUTIANS EAST BOROU",
         "DATA":"456"
      }
   ]
}
</script>

JavaScript

var statesObj = $.parseJSON(document.getElementById('myJson').innerHTML).stuff,
    finalObj = {
        USA : {
            name: "USA",
            children: []
        }
    };
for (var st = 0; st < statesObj.length; ++st) {
    // First the states
    if( statesObj[st].County_Code === "000") {
        var newState = {
            name: statesObj[st].County_Name,
            abbrv: statesObj[st].State_Abbrv,
            children: []
        };
        finalObj.USA.children.push(newState);
    }
}

for (var st = 0; st < statesObj.length; ++st) {
    // Now the rest
    if( statesObj[st].County_Code !== "000") {
        var newChild = {
            name: statesObj[st].County_Name,
            data: statesObj[st].DATA
        };
        for (var sub in finalObj.USA.children) {
            if (finalObj.USA.children.hasOwnProperty(sub) &&
                finalObj.USA.children[sub].abbrv === statesObj[st].State_Abbrv) {
                finalObj.USA.children[sub].children.push(newChild);
                break;
            }
        }
    }
}

var finalJson = JSON.stringify(finalObj);
console.log(finalJson);