Nested grouping in array of objects with id and date?

I have an array of json objects as

[
  {
    "businessId": "7ab43023-7f40-40cf-b97c-563223bb27ef",
    "id": "38fe3c68-e6aa-4c57-b4d7-dc6c4f597269",
    "journalDate": "2020-08-13T00:00:00.000Z",
    "transactionId": "146",
    "accountId": "4",
    "amount": 85,
    "isReconciled": 0,
    "active": 1,
    "createdAt": "2020-08-14T02:55:43.988Z",
    "updatedAt": "2020-08-14T02:55:43.988Z"
  },
  {
    "id": "45bf4792-c5a5-44ed-b7e8-57557c4f30ee",
    "journalDate": "2020-08-13T00:00:00.000Z",
    "transactionId": "160",
    "accountId": "4",
    "amount": 70,
    "isReconciled": 0,
    "active": 1,
    "createdAt": "2020-08-14T02:55:43.988Z",
    "updatedAt": "2020-08-14T02:55:43.988Z"
  },
  {
    "id": "5fe82eb0-17cc-4a08-97cf-0291b4b2b740",
    "journalDate": "2020-08-13T00:00:00.000Z",
    "transactionId": "158",
    "accountId": "4",
    "amount": 274.5,
    "isReconciled": 0,
    "active": 1,
    "createdAt": "2020-08-14T02:55:43.988Z",
    "updatedAt": "2020-08-14T02:55:43.988Z"
  },
  {
    "id": "6690f228-35c1-4ba7-a0ff-a3e6a64cbc88",
    "journalDate": "2020-06-30T00:00:00.000Z",
    "transactionId": "151",
    "accountId": "4",
    "amount": -100,
    "isReconciled": 0,
    "active": 1,
    "createdAt": "2020-08-14T02:55:43.988Z",
    "updatedAt": "2020-08-14T02:55:43.988Z"
  },
  {
    "id": "89a0e960-943d-4f0a-a81c-44d1ec27de59",
    "journalDate": "2020-05-31T00:00:00.000Z",
    "transactionId": "153",
    "accountId": "4",
    "amount": -60,
    "isReconciled": 0,
    "active": 1,
    "createdAt": "2020-08-14T02:55:43.988Z",
    "updatedAt": "2020-08-14T02:55:43.988Z"
  }
]

Now i want to group data for same accountid for a year. For example

{
  "accountId": "4",
  "Jan": [
    {
      "businessId": "7ab43023-7f40-40cf-b97c-563223bb27ef",
      "id": "38fe3c68-e6aa-4c57-b4d7-dc6c4f597269",
      "journalDate": "2020-01-13T00:00:00.000Z",
      "transactionId": "146",
      "accountId": "4",
      "amount": 85,
      "isReconciled": 0,
      "active": 1,
      "createdAt": "2020-08-14T02:55:43.988Z",
      "updatedAt": "2020-08-14T02:55:43.988Z"
    }
  ],
  "Feb": [
    {
      "businessId": "7ab43023-7f40-40cf-b97c-563223bb27ef",
      "id": "38fe3c68-e6aa-4c57-b4d7-dc6c4f597269",
      "journalDate": "2020-02-13T00:00:00.000Z",
      "transactionId": "146",
      "accountId": "4",
      "amount": 85,
      "isReconciled": 0,
      "active": 1,
      "createdAt": "2020-08-14T02:55:43.988Z",
      "updatedAt": "2020-08-14T02:55:43.988Z"
    }
  ]
}

Please guide me how can achieve this ?

Answer

Use forEach over items and Build an object with keys and accountId (have separate buckets for each month). Get Object.values from the object just built.

const transform = (arr) => {
  const all = {};
  arr.forEach(({ accountId, journalDate, ...rest }) => {
    if (!all[accountId]) {
      all[accountId] = { accountId };
    }
    const month = new Date(journalDate)
      .toDateString()
      .split(" ")[1];
    if (!all[accountId][month]) {
      all[accountId][month] = [];
    }
    all[accountId][month].push({ accountId, journalDate, ...rest });
  });
  return Object.values(all);
};

const data = [
  {
    businessId: "7ab43023-7f40-40cf-b97c-563223bb27ef",
    id: "38fe3c68-e6aa-4c57-b4d7-dc6c4f597269",
    journalDate: "2020-08-13T00:00:00.000Z",
    transactionId: "146",
    accountId: "4",
    amount: 85,
    isReconciled: 0,
    active: 1,
    createdAt: "2020-08-14T02:55:43.988Z",
    updatedAt: "2020-08-14T02:55:43.988Z",
  },
  {
    id: "45bf4792-c5a5-44ed-b7e8-57557c4f30ee",
    journalDate: "2020-08-13T00:00:00.000Z",
    transactionId: "160",
    accountId: "4",
    amount: 70,
    isReconciled: 0,
    active: 1,
    createdAt: "2020-08-14T02:55:43.988Z",
    updatedAt: "2020-08-14T02:55:43.988Z",
  },
  {
    id: "5fe82eb0-17cc-4a08-97cf-0291b4b2b740",
    journalDate: "2020-08-13T00:00:00.000Z",
    transactionId: "158",
    accountId: "4",
    amount: 274.5,
    isReconciled: 0,
    active: 1,
    createdAt: "2020-08-14T02:55:43.988Z",
    updatedAt: "2020-08-14T02:55:43.988Z",
  },
  {
    id: "6690f228-35c1-4ba7-a0ff-a3e6a64cbc88",
    journalDate: "2020-06-30T00:00:00.000Z",
    transactionId: "151",
    accountId: "4",
    amount: -100,
    isReconciled: 0,
    active: 1,
    createdAt: "2020-08-14T02:55:43.988Z",
    updatedAt: "2020-08-14T02:55:43.988Z",
  },
  {
    id: "89a0e960-943d-4f0a-a81c-44d1ec27de59",
    journalDate: "2020-05-31T00:00:00.000Z",
    transactionId: "153",
    accountId: "4",
    amount: -60,
    isReconciled: 0,
    active: 1,
    createdAt: "2020-08-14T02:55:43.988Z",
    updatedAt: "2020-08-14T02:55:43.988Z",
  },
];

console.log(transform(data));