How to provide default value in if condition in sightly

[manu_tomar]

I have a scenario where I have to provide a default value in data-sly-test expression if expression property does't exists. like below

     <sly data-sly-test="${properties.abc | 'xyz'}"> ${properties.pqr} </sly>

​Please help on this.

[Feike_Visser1]

to me you can do this with ||