dataweave - How to join the list of sku with same order in one object in the array

Hi The best way as shown by Salim is the groupBy I did a few modifications

%dw 2.0
output application/json
---
payload 
    groupBy ((item, index) -> item.number)
    mapObject ((value, key, index) -> 
        {
            number: key,
            list: value map ((item, index) -> item - "number") //We remove the number field
        }
    )

Simple the key of the groupBy is the criteria that was group so it is the number and the simplest way to re build the output structure is by doing the map and removing the "number" field

Try this script:

%dw 2.0
output application/json
---
payload groupBy $.number mapObject ((value, key, index) -> {
           number: value.number[0],
           list: value reduce ((item1, a =[]) -> a + { sku: item1.sku ,  desc: item1.desc})
}
)

Here is the updated script that matches the output:

%dw 2.0
output application/json
---
payload groupBy $.number pluck $ map ((item,index) -> {
           number: item.number[0],
           list: item reduce ((item1, a =[]) -> a + { sku: item1.sku ,  desc: item1.desc})
}
)

As other experienced members have mentioned, groupBy is the right way to achieve this. However, I noticed there is a difference in the output with the given approaches. The following script will output an array of items.

Script is updated to add shippingDate based on the new changes provided in the comment. Assumption is shippingDate is same for an order (number).

%dw 2.0
output application/json
var itemByNumber = payload groupBy ((item) -> item.number)
var removeKeys = ["number", "shippingDate"]
---
keysOf(itemByNumber) map ((key) -> 
do  {
    var item = itemByNumber[key]
    ---
    {
        number: key,
        shippingDate: item[0].shippingDate,
        list: item map ($ -- removeKeys)
    }
})

Output

[
  {
    "number": "7358",
    "shippingDate": "28/04/2022",
    "list": [
      {
        "sku": "301-01",
        "desc": "1"
      },
      {
        "sku": "301-02",
        "desc": "2"
      }
    ]
  },
  {
    "number": "7359",
    "shippingDate": "29/04/2022",
    "list": [
      {
        "sku": "301-03",
        "desc": "3"
      },
      {
        "sku": "301-03",
        "desc": "4"
      }
    ]
  },
  {
    "number": "7360",
    "shippingDate": "27/04/2022",
    "list": [
      {
        "sku": "301-03",
        "desc": "5"
      }
    ]
  }
]

Input

[
  {
    "number": "7358",
    "shippingDate":"28/04/2022",
    "sku": "301-01",
    "desc": "1"
  },
  {
    "number": "7358",
    "shippingDate":"28/04/2022",
    "sku": "301-02",
    "desc": "2"
  },
  {
    "number": "7359",
    "shippingDate":"29/04/2022",
    "sku": "301-03",
    "desc": "3"
  },
  {
    "number": "7359",
    "shippingDate":"29/04/2022",
    "sku": "301-03",
    "desc": "4"
  },
  {
    "number": "7360",
    "shippingDate":"27/04/2022",
    "sku": "301-03",
    "desc": "5"
  }
]