JSFiddle - React, Tailwind, and code Playground

JavaScript

var before = {
    "message": "Successfully Advisor data has been fetched.",
    "success": true,
    "data": {
        "dataHeaders": ["Carrier","B2B", "EM"],    
        "dataArray": {
            "DHL": ["DHL", "45", "5","5"],
            "Fedex": ["Fedex","40", "7","6"],
            "UPS" : ["UPS","30", "10","3"],
            "TNT" : ["TNT","30", "10","3"],
        }
    }
};


parseData = function (jsonData) {
    var result = [];
    jsonData.data.dataHeaders.forEach(function (carrier, indexHeader) {
        var el = {}
        el.key = carrier;
        el.values = []; 
        
        // shortcut
        dataArray = jsonData.data.dataArray;
        // generate sub elements
        for (arr in dataArray) {
            
            // generate element
            subEl = {};
            subEl.x = arr;
            subEl.y = dataArray[arr][indexHeader + 1];
            // add to array
            el.values.push(subEl);
        }
       
        // add el to result
        result.push(el);
    });
  return result;
}

var after = parseData(before);

alert(JSON.stringify(after));

console.log("before: ", before);
console.log("after: ", after);