空变量赋值时的DataWeave最佳做法

Question

This is a JSON-JSON transformation, transforming a boolean input ("true"|"false") into a char output ('Y'|'N') . So we go for something like:

varOutput: ('Y' when payload.varInput otherwise 'N')

But what if varInput is null? we got exception. I could control it with another when-otherwise:

varOutput: ('Y' when payload.varInput != null otherwise 'N')
when payload.varInput != null otherwise null,

This last one is null safe, but again, I feel there should be a more elegant way.

Answer 1

Use default

{varOutput: ( payload.varInput default 'N')
 }

Or unless/otherwise is null safe and a bit more elegant:

{ 
    varOutput: ('Y' unless payload.varInput !=null otherwise 'N')
}