Need to add similar customer into array after performing groupBy but with a limit per customer

Question

I had asked a similar question yesterday and got a correct answer, but today I faced more issues. So here is the new problem statement. I am fetching customer contacts from salesforce which are coming as an array of objects as shown below.

Input Payload:

[
    {
        "customerID": 1,
        "customerName": "Jonhn1"
    },
    {
        "customerID": 1,
        "customerName": "Jonhn2"
    },
    {
        "customerID": 1,
        "customerName": "Jonhn3"
    },
    {
        "customerID": 1,
        "customerName": "Jonhn4"
    },
    {
        "customerID": 1,
        "customerName": "Jonhn5"
    },
    {
        "customerID": 2,
        "customerName": "Jonhn6"
    },
    {
        "customerID": 2,
        "customerName": "Jonhn7"
    },
    {
        "customerID": 2,
        "customerName": "Jonhn8"
    },
    {
        "customerID": 3,
        "customerName": "Jonhn9"
    },
    {
        "customerID": 3,
        "customerName": "Jonhn10"
    },
    {
        "customerID": 3,
        "customerName": "Jonhn11"
    },
    {
        "customerID": 4,
        "customerName": "Jonhn12"
    },
    {
        "customerID": 4,
        "customerName": "Jonhn13"
    },
    {
        "customerID": 5,
        "customerName": "Jonhn14"
    },
    {
        "customerID": 5,
        "customerName": "Jonhn15"
    },
    {
        "customerID": 5,
        "customerName": "Jonhn16"
    },
    {
        "customerID": 6,
        "customerName": "Jonhn17"
    },
    {
        "customerID": 7,
        "customerName": "Jonhn17"
    }
]

I need the output to be an array of arrays, each sub-array should have all the customer details of at most three different customers. I got the solution till the above statement as show below

%dw 2.0
output application/json
import * from dw::core::Arrays
---
payload groupBy $.customerID pluck $ divideBy 3 map((flatten($)))

Now the main problem, We have to put a limit on the number of customers in an array. For example in the given input payload customer with id "1" came more than 4 (four) times, then this customer should be in a different array ( means a separate array of customer "1" e.g an array for five records) this can happen to any other customer as well.

So we have to check if a customer is repeating more than 4 times then make a separate array for that type of customer else combine it with other customers as required earlier

Expected output:

[
    [
        {
            "customerID": 1,
            "customerName": "Jonhn1"
        },
        {
            "customerID": 1,
            "customerName": "Jonhn2"
        },
        {
            "customerID": 1,
            "customerName": "Jonhn3"
        },
        {
            "customerID": 1,
            "customerName": "Jonhn4"
        },
        {
            "customerID": 1,
            "customerName": "Jonhn5"
        }
    ],
    [
        {
            "customerID": 2,
            "customerName": "Jonhn6"
        },
        {
            "customerID": 2,
            "customerName": "Jonhn7"
        },
        {
            "customerID": 2,
            "customerName": "Jonhn8"
        },
        {
            "customerID": 3,
            "customerName": "Jonhn9"
        },
        {
            "customerID": 3,
            "customerName": "Jonhn10"
        },
        {
            "customerID": 3,
            "customerName": "Jonhn11"
        },
        {
            "customerID": 4,
            "customerName": "Jonhn12"
        },
        {
            "customerID": 4,
            "customerName": "Jonhn13"
        }
    ],
    [
        {
            "customerID": 5,
            "customerName": "Jonhn14"
        },
        {
            "customerID": 5,
            "customerName": "Jonhn15"
        },
        {
            "customerID": 5,
            "customerName": "Jonhn16"
        },
        {
            "customerID": 6,
            "customerName": "Jonhn17"
        },
        {
            "customerID": 7,
            "customerName": "Jonhn18"
        }
    ]
]

Answer 1

Please verify all the scenarios and correct me if anything I missed. I just seggregated based on the size of individual array.

If size[array] > 4 then divideBy 5 else divideBy 3.

distinctBy to maintain a single payload as I have used payload in if and else condition

Note -> Order will not be maintained as you mentioned for rainy scenarios.

%dw 2.0
output application/json
import * from dw::core::Arrays
var a = payload groupBy $.customerID pluck $
---
flatten(a map
    (if (sizeOf($)>4)  
            $ divideBy sizeOf($) map(flatten($))
            else
    (a filter (sizeOf ($)< 5) divideBy 3 map (flatten ($))) 
    ) distinctBy $)

Output

[
  [
    {
      "customerID": 1,
      "customerName": "Jonhn1"
    },
    {
      "customerID": 1,
      "customerName": "Jonhn2"
    },
    {
      "customerID": 1,
      "customerName": "Jonhn3"
    },
    {
      "customerID": 1,
      "customerName": "Jonhn4"
    },
    {
      "customerID": 1,
      "customerName": "Jonhn5"
    }
  ],
  [
    {
      "customerID": 2,
      "customerName": "Jonhn6"
    },
    {
      "customerID": 2,
      "customerName": "Jonhn7"
    },
    {
      "customerID": 2,
      "customerName": "Jonhn8"
    },
    {
      "customerID": 2,
      "customerName": "Jonhn9"
    },
    {
      "customerID": 3,
      "customerName": "Jonhn10"
    },
    {
      "customerID": 3,
      "customerName": "Jonhn11"
    },
    {
      "customerID": 4,
      "customerName": "Jonhn12"
    },
    {
      "customerID": 4,
      "customerName": "Jonhn13"
    }
  ],
  [
    {
      "customerID": 5,
      "customerName": "Jonhn14"
    },
    {
      "customerID": 5,
      "customerName": "Jonhn15"
    },
    {
      "customerID": 5,
      "customerName": "Jonhn16"
    },
    {
      "customerID": 6,
      "customerName": "Jonhn17"
    },
    {
      "customerID": 7,
      "customerName": "Jonhn17"
    }
  ]
]