Rename JSON Keys

DataWeave 2.1 is compatible with Mule 4.1. Standard Support for Mule 4.1 ended on November 2, 2020, and this version of Mule will reach its End of Life on November 2, 2022, when Extended Support ends.

Deployments of new applications to CloudHub that use this version of Mule are no longer allowed. Only in-place updates to applications are permitted.

MuleSoft recommends that you upgrade to the latest version of Mule 4 that is in Standard Support so that your applications run with the latest fixes and security enhancements.

This DataWeave 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
%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
{
  "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
[
  {
    "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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