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Example: Renaming JSON Keys

This example renames some keys in a JSON object, while retaining the names of all others in the output.

It uses these functions:

  • mapObject to go through the key:value pairs in a JSON object.

  • if by itself to determine when to change the name of a key.

  • if with and to retain the name of all keys except the two with new names.

  • as to coerce the type of the keys into a String.

DataWeave

         
      
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%dw 2.0
output application/json
---
payload.flights map (flight) -> {
    (flight mapObject (value, key) -> {
        (emptySeats: value) if(key as String == 'availableSeats'),
        (airline: value) if(key as String == 'airlineName'),
        ((key):value) if(key as String !='availableSeats' and key as String != 'airlineName')
    })
}
Input

         
      
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{
  "flights":[
  {
  "availableSeats":45,
  "airlineName":"Ryan Air",
  "aircraftBrand":"Boeing",
  "aircraftType":"737",
  "departureDate":"12/14/2017",
  "origin":"BCN",
  "destination":"FCO"
  },
  {
  "availableSeats":15,
  "airlineName":"Ryan Air",
  "aircraftBrand":"Boeing",
  "aircraftType":"747",
  "departureDate":"08/03/2017",
  "origin":"FCO",
  "destination":"DFW"
  }]
}
Output

         
      
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[
  {
    "emptySeats": 45,
    "airline": "Ryan Air",
    "aircraftBrand": "Boeing",
    "aircraftType": "737",
    "departureDate": "12/14/2017",
    "origin": "BCN",
    "destination": "FCO"
  },
  {
    "emptySeats": 15,
    "airline": "Ryan Air",
    "aircraftBrand": "Boeing",
    "aircraftType": "747",
    "departureDate": "08/03/2017",
    "origin": "FCO",
    "destination": "DFW"
  }
]

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