group by property

[bhojendra]

As in my initial post, I want the result as like:

result = [
  { // n is 1
    "g": [
      {
        "name": "John",
        "n": 1
      },
      {
        "name":"Alina",
        "n": 1
      }
    ],
    "b": [
      {
        "name": "...",
        "n": 1
      },
      {
        "name": "...",
        "n": 1
      }
    ]
  },
  { // n is 2
    "g": [...],
    "b": [...]
  },
  { // n is 3
   // ...
  }
]

And I think I understood one liner syntax. I will try this.