Polymer add class when property is true

I have seen this in angular before and wondered if this is possible in polymer as well. Angular - What is the best way to conditionally apply a class?

I have set up a property named 'animated':

animated: {
  type: Boolean,
  value: false,
},

When animated is true, a div inside my element should have a css class of .animate.

For now I have done that inside of the ready function.
But since I came across that Stackoverflow question I wondered if this is prossible in polymer.

Thanks!

Answer

One way to do that is using a function as follow:

Where class$ with $ symbol indicates to Polymer's that property is generate using data binding. So, your _getClass function will look like this:

_getClass: function(animated){
   return animated ? "animate" : "";

}

When animate property changes, the _getClass function will be invoked and this function will return the string that indicates the class you need.