CODEWITHSUNDEEP
dataweavemulesoft
Rohit Kakani
Rohit Kakani

Reputation: 25

Better way of doing a Null check in Dataweave Mule

I usually do a null check in Dataweave, as below,

{ payload.variableA when payload != null otherwise null }

But one of my Collegue has suggested me to use default {} to reduce the null checks, like below,

%var x = payload default {}
{
payload.variableA
}

As it improves readability, especially in complex transformations.

But is it really a good practice to do this way? Will it cause any issues, like creating unnecessary empty objects?

Upvotes: 0

Views: 5323

Answers (1)

Michael Jones
Michael Jones

Reputation: 1910

First, payload.variableA should return null when payload is null. You don't need to do a check on that. Attempting to access a key on a null object returns null rather than throwing something like a null-pointer exception you might be used to.

You can think of default as the null-coalesce operator for dataweave. You can set it to an empty object, a default value, etc etc.

https://docs.mulesoft.com/mule-runtime/4.3/dataweave-cookbook-defaults

The default operator behaves the same in DW1 and DW2.

Upvotes: 2

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