Dynamic mapping in Dataweave

Question

I'm trying to map a column name dynamically in Dataweave using the contents of a flow variable. The static version of what I'm trying to achieve looks something like:

payload map ((payload01 , indexOfPayload01) -> {
    COLUMNA: payload01.INPUTA
})

Now the part that I need to be dynamic is INPUTA - I need the A to be derived from a flow variable that is set prior to the Dataweave component. I've tried something like:

payload map ((payload01 , indexOfPayload01) -> {
    COLUMNA: payload01.INPUT#flowVars['varName']
})

But I'm getting a com.mulesoft.weave.grammar.InvalidNamespacePrefixException error.

Is this possible to achieve in Dataweave? Can't seem to find any relevant docs describing how.

Manik Magar Manik Magar · Accepted Answer · 2016-04-28T14:10:11

Use it like below. Note the parenthesis around key which is very important because () tells DataWeave to first execute script inside it and then use the result as the value for outside expression.

    payload map ((payload01 , indexOfPayload01) -> {
    COLUMNA: payload01[('INPUT' ++ flowVars.varName)]
})

Let me know that doesn't work.

I see your key name is COLUMNA, you can also append varName to key by using ().

Dynamic mapping in Dataweave

3 Answers