JSFiddle - React, Tailwind, and code Playground

JavaScript

let dataArr = [{
  Name: 'Rick',
  City: 'Sunnyvale',
  FactorJSONMap: `{
    "Id": 673,
    "Country": "USA"
  }`
}, {
  Name: 'Diana',
  City: 'Santa Clara',
  FactorJSONMap: `{
    "Id": 673,
    "Country": "USA"
  }`
}, {
  Name: 'Thiago',
  City: 'New Jeresy',
  FactorJSONMap: `{
  "Id": 673,
  "Country": "USA"
}`
}];

function traverseData(data) {
  for(let data_obj of data) {
  Object.assign(data_obj, JSON.parse(data_obj.FactorJSONMap));
  delete data_obj.FactorJSONMap;
  }
  return data;
};
console.log(
	traverseData(dataArr)
);