CODEWITHSUNDEEP
dataweavemule4
Satyam Pisal
Satyam Pisal

Reputation: 126

Dataweave Transformation based on 'if key present or not'

I need to do dataweave transformation of the key, if it is present and not if the key is not present.

Sample Input

[
  {
    "Key1": "Value1",
    "Key2": {
         "Key2.1": "value2.1",
         "Key2.2": "Value2.2" 
         },
    "Key3": "Value3",
  },
  {
    "Key1": "Value11",
    "Key2": {
         "Key2.1": "value22.1"
         }
  }
]

Sample OutPut

[
  {
    "KeyA": "Value1",
    "KeyB": {
         "KeyB.1": "value2.1",
         "KeyB.2": "Value2.2" 
         },
    "KeyC": "Value3"
  },
  {
    "KeyA": "Value11",
    "KeyB": {
         "KeyB.1": "value22.1"
         }
  }
]

Not Expected

[
  {
    "KeyA": "Value1",
    "KeyB": {
         "KeyB.1": "value2.1",
         "KeyB.2": "Value2.2" 
         },
    "KeyC": "Value3"
  },
  {
    "KeyA": "Value11",
    "KeyB": {
         "KeyB.1": "value22.1"
         "KeyB.2": null
         },
    "KeyC": null
  }
]

Question1: Is it really a JSON format?

Question2: How to do such transformation in DW 2.0?

Thanks in advance :)

Upvotes: 0

Views: 972

Answers (2)

aled
aled

Reputation: 25872

  1. The input is not a valid JSON document because there is an extra comma after Key3, though it is not clear if that is what you are asking or why.

  2. After removing the comma the input is a JSON array of two JSON objects. You can use map() to transform each element and then use mapObject() to transform the keys in each object. mapObject() will not create new keys, only transform the existing ones, so there is no risk of creating new ones. As an example I use a transformKey() to encapsulate the desired transformation of the key. I'm using the built-in lower() function, but you could use whatever logic you want to transform the key.

%dw 2.0
output application/json 
fun transformKey(k)= lower(k) 
---
payload map (
    $ mapObject ((value, key, index) -> (transformKey(key)): value )
)

Upvotes: 1

machaval
machaval

Reputation: 5059

There are two ways to do this kind of things,

  1. Is to use conditional elements on an object conditional element
{
   (a: payload.a) if(payload.a?)
}
  1. There is a writer property to avoid writing nulls skipNullOn
output application/json skipNullOn="everywhere"
---
{
  a: payload.a
}

Upvotes: 3

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