MuleSoft Dataweave- Combining Key Value Pairs from Different Objects with Same Keys

Question

I have a payload of an array of objects. Within each object contains a key that has values that are also arrays of objects. I am trying to combine all of the keys that match, and condense down to an array of the values at the smallest level.

Here is an example payload-

[
    {
        "randomNumbers": [
            {
                "aFewDigits": "124374"
            }
        ]
    },
    {
        "randomNumbers": [
            {
"aFewDigits": "103865"
            },
            {
                "aFewDigits": "103868"
            },
            {
                "aFewDigits": "103739"
            },
            {
"aFewDigits": "103866"
            }
        ]
    },
    {
        "randomNumbers": [
            {
                "aFewDigits": "103864"
            },
            {
                "aFewDigits": "103737"
            },
            {
                "aFewDigits": "103862"
            },
            {
                "aFewDigits": "103860"
            }
        ]
    }
]

I've tried using this dataweave map script to pull out the values from each array-

%dw 2.0
output application/json
---
payload map{
    aFewDigits: $..aFewDigits
}

However, this is the result I am getting-

[
  {
    "aFewDigits": [
      "124374"
    ]
  },
  {
    "aFewDigits": [
      "103865",
      "103868",
      "103739",
      "103866"
    ]
  },
  {
    "aFewDigits": [
      "103864",
      "103737",
      "103862",
      "103860"
    ]
  }
]

I would like for my result to look like this-

[
  {
    "aFewDigits": [
      "124374",
      "103865",
      "103868",
      "103739",
      "103866",
      "103864",
      "103737",
      "103862",
      "103860"
    ]
  }
]

score 2 · Answer 1 · answered Apr 24 '23 at 22:31

A solution with just using selectors and flatten():

%dw 2.0
output application/json
---
[aFewDigits: flatten(payload.randomNumbers).aFewDigits]

Output:

[
  {
    "aFewDigits": [
      "124374",
      "103865",
      "103868",
      "103739",
      "103866",
      "103864",
      "103737",
      "103862",
      "103860"
    ]
  }
]

An alternative solution using flatMap():

%dw 2.0
output application/json
---
[aFewDigits: payload.randomNumbers flatMap $.aFewDigits]

score 2 · Accepted Answer · answered Apr 25 '23 at 03:28

Just customizing your solution. You dont need to apply map for your solution since descendant keys are same. You can refer Dataweave Selectors for further details

DataWeave

%dw 2.0
output application/json
---
["aFewDigits":payload..aFewDigits]

Output

[
  {
    "aFewDigits": [
      "124374",
      "103865",
      "103868",
      "103739",
      "103866",
      "103864",
      "103737",
      "103862",
      "103860"
    ]
  }
]

score 0 · Answer 3 · answered Apr 24 '23 at 22:10

You can achieve the desired output by using the reduce function

The script iterates over each item in the input array using the reduce function. For each item, it concatenates the aFewDigits arrays of all the items into a single array. Finally, it returns an object with the concatenated aFewDigits array.

DataWeave Script

%dw 2.0
output application/json
---
payload reduce ((item, acc = {aFewDigits: []}) -> {aFewDigits: acc.aFewDigits ++ item.randomNumbers.*aFewDigits})

Output:

{
  "aFewDigits": [
    "124374",
    "103865",
    "103868",
    "103739",
    "103866",
    "103864",
    "103737",
    "103862",
    "103860"
  ]
}

The output misses an array level above. – aled Apr 24 '23 at 22:33 — aled, Apr 24 '23 at 22:33

MuleSoft Dataweave- Combining Key Value Pairs from Different Objects with Same Keys

3 Answers3