Optional chaining to add a "data-attribute" on PugJS

I am looking for a solution to add "optional chaining" on PugJS to set data-active="true" if i === 0.

Bellow is my current code. This code is working, but the problem with this approach (bellow) is that I have to repeat my code on a else statement and that doesn't make sense. I have to add (i === 0 ? 'data-active="true"' : '') on the .my__element, but I don't know how to do it.

if (i === 0)
  .my__element(data-month=months[month] data-active="true")
else
  .my__element(data-month=months[month])

Any help please? Thank you