Best way to merge two objects and sum the values of same key?

I have two objects similar to this:

let data = [[
  {
    10: {key1: 1, key2: 2, key3: 3},
    11: {key1: 1, key2: 2, key3: 3},
    12: {key1: 1, key2: 2, key3: 3},
    },
  {},
  {}
],
[
  {
    10: {key1: 1, key2: 2, key3: 3},
    11: {key1: 1, key2: 2, key3: 3},
    12: {key1: 1, key2: 2, key3: 3},
    },
  {},
  {}
]]

I wanna create a new object and sum every value of each key. Like this:

let newData = [
      {
        10: {key1: 2, key2: 4, key3: 6},
        11: {key1: 2, key2: 4, key3: 6},
        12: {key1: 2, key2: 4, key3: 6},
        },
      {},
      {}
    ]

Each object has three object in them. In these three objects, there is 45 keys, each of them has a object with three keys/values.

I can't find any good solution to sum every value.

My current solution is that I first loop thru data:

let count = 0;
let count2 = 0;
for(let ob of data){
     for(let child in ob[0]){
          keyOne = ob[0][child].keyOne;
          keyTwo = ob[0][child].keyTwo;
          keyThree = ob[0][child].keyThree;
          keyFour = ob[0][child].keyFour;
          if(count < 45) {
               newData[0][count].keyOne += keyOne;
               newData[0][count].keyTwo += gkeyTwop;
               newData[0][count].keyThree += keyThree;
               newData[0][count].keyFour += keyFour;
          } else {
               newData[0][count2].keyOne += keyOne;
               newData[0][count2].keyTwo += keyTwo;
               newData[0][count2].keyThree += keyThree;
               newData[0][count2].keyFour += keyFour;
               count2++;

          }
          count++;
     }

In the worst case, data got three objects with 45 keys each. Then I must do this three times. This seems really bad. There must be a better way. Tips?

via mintermasher