Tester function for efficient and inefficient function

tester_eff_ineff_noob.js

function get_data_set(which){
  var all_data_set={ 
  basic:[
    {make: "Jeep",model: "Cherokee",trim:"Sport 4dr Front-wheel Drive",year:"2016",wheel:{wheel_size:"17 x 7.5",
    wheel_metal:"Aluminum"}},
    {make: "Jeep",model: "Compass",trim:"Latitude 4dr Front-wheel Drive",year:"2014",
    wheel:{wheel_metal:"Steel"}},
    {make: "Jeep",model: "Patriot",trim:"Sport 4dr 4x4"}, 
    {make: "Jeep",model: "Wrangler",trim:"Sahara 2dr 4x4",year: "2015"}
  ] 
  }
  
  var res = all_data_set[which]
  
  return res;
  
}