OneDrive Trigger Condition - Only trigger if an excel file

[Ckatz]

Hello,

I have a workflow that uses the OneDrive When a file is created trigger. I would like to add a trigger condition that would only trigger the workflow if the file extension is .xls, .xlsm or .xlsx

I tried using the following trigger condition: @contains(base64ToString(triggerOutputs()?['headers/x-ms-file-name-encoded']), 'xls')

I am getting the following error:

Any thoughts on what the trigger condition should be?

Thanks