var gifts = [
  {name:"partridge", type : "bird"},
  {name:"turtle dove", type : "bird"},
  {name:"french hen", type : "bird"},
  {name:"calling bird", type : "bird"},
  {name:"gold ring", type : "jewlery"},
  {name: "goose", type:"bird"},
  {name: "swan", type: "bird"},
  {name: "milk maid", type: "person"},
  {name: "lady dancing", type: "person"},
  {name: "leaping lord", type: "person"},
  {name: "piper", type: "person"},
  {name: "drummer", type: "person"}
];
function numberOfTotalGifts(day=12){
  var sum = 0;
  for(let n = 0; n < day; n++){
    sum += 0.5*n*(n+1);
  }
  return sum
}

function totalTypesOfGifts(day = 12){
  var sums = {};
  for(let n = 0; n < day; n++){
    for(let g = 0; g < n+1; g++){
      if(sums.hasOwnProperty(gifts[g].type) == false){
        sums[gifts[g].type] = g+1;
      }else{
        sums[gifts[g].type] += g+1;
      }
    }
  }
  return sums;
}

function totalGiftsByName(day = 12){
  var sums = {};
  for(let n = 0; n < day; n++){
    for(let g = 0; g < n+1; g++){
      if(sums.hasOwnProperty(gifts[g].name) == false){
        sums[gifts[g].name] = g+1;
      }else{
        sums[gifts[g].name] += g+1;
      }
    }
  }
  return sums;
}