Map and Reduce a JSON Object with JavaScript

Question

Consider this object below:

    {
    "_items": [
        {
            "_id": "player_1",
            "score": {
                "a": -4.74,
                "b": 0.71,
                "c": -4.04,
                "d": 3.37,
                "e": 0.22,
                "f": 1.09,
                "g": -2.17              
            }
        }
    ]
}

I would to Map and Reduce and generate a new object containing only the score object :

{
    "a": -4.74,
    "b": 0.71,
    "c": -4.04,
    "d": 3.37,
    "e": 0.22,
    "f": 1.09,
    "g": -2.17
}

I was thinking something like this might be moving in the right directions, but does not seem to do what I was expecting:

this.service.getscore()
  .map(res => res.json())
  .map(v => v._items[0].score)
  .subscribe(data => { this.sc = data });

console.log(this.sc); will give me the same result as the first json.

While I recognize that it is probably better and easier to do this on the server-side, it's not possible in my case. I am wondering if what I am trying to do can be done on the client side with JavaScript. Any suggestions?

Solution

Could you try my code below:

var item = {
  "_items": [{
      "_id": "player_1",
      "score": {
        "a": -4.74,
        "b": 0.71,
        "c": -4.04,
        "d": 3.37,
        "e": 0.22,
        "f": 1.09,
        "g": -2.17
      }
    },
    {
      "_id": "player_2",
      "score": {
        "a": -4.74,
        "b": 0.71,
        "c": -4.04,
        "d": 3.37,
        "e": 0.22,
        "f": 1.09,
        "g": -2.17
      }
    }
  ]
};
let arrayScores = item._items.map(el => el.score);
console.log(arrayScores);

There is the arrayScores value:

[{
  a: -4.74,
  b: 0.71,
  c: -4.04,
  d: 3.37,
  e: 0.22,
  f: 1.09,
  g: -2.17
}, {
  a: -4.74,
  b: 0.71,
  c: -4.04,
  d: 3.37,
  e: 0.22,
  f: 1.09,
  g: -2.17
}]

Does it make sense ?