Optional attributes?

[yacoob]

Context: I'm trying to use ACE within Hugo. Is there a way to an attribute optional? I want to have a div that has an attribute only if a template variable is set. In other words: Right now if I say:

div data-foo={{ .foo }}

I'll get

<div data-foo="">

What do I need to say to get

<div>

if .foo is not set?