JSFiddle - React, Tailwind, and code Playground

JavaScript

var arr = ['adam', 'smith', 'honda', 'civic']

var obj = {
  first_name : 0,
  last_name: 1,
  car : {
    make: 2,
    model: 3
  }
}

function mapObj(o, a)
{
    Object.keys(o).forEach(function(key){
        var objType = typeof(o[key]);
        if(objType === "object")
        {
            mapObj(o[key], a);
        }
        else
        {
            o[key] = a[o[key]];
        }
	});
    
}

mapObj(obj, arr);

console.log(obj);