How to know if an object is dynamic in AS3

In Action Script 3, you can write a class that defines a dynamic object (MovieClip and Object are two examples), this objects can be modified in run-time. What I want to know if is there some way (in run-time, of course) to know if certain object is dynamic or not.

PS: Without making something like this:

function isDynamic(object) {
    try {
        object.newProperty = 'someValue'
    } catch (e) {
        return false
    }
    return true
}

From stackoverflow

• You can use describeType from flash.utils to describe the object in XML form. Here's the reference to the API: flash.utils.describeType

  function isDynamic(object) {
      var type:XML = describeType(object);
      if(type.isDynamic) return true;
      return false;
  }
  

  unkiwii : "if (type.isDynamic) return true". I think this can be made by just "return type.isDynamic"

• CookieOfFortune has the right idea, but unfortunately the code itself has problems, isDynamic is an attribute, and the returned value will be a XMLList with a value of a String that reflects a true or false value, not a child node that directly returns a Boolean. It should look more like this:

  function isDynamic(object) : Boolean
  {
      var type:XML = describeType(object);
      return type.@isDynamic.toString() == "true";
  }

  CookieOfFortune : yeah, I was lazy.

  Franky-D : But what if you want to test for dynamic in order to avoid a call to describeType.. sigh.

• Be careful!

  Anytime you want to use the describeType() function, please please please use the variation:

  import mx.utils.DescribeTypeCache;
  var typeDesc:XML = DescribeTypeCache.describeType(object).typeDescription;
  

  Performance of making repeated calls to the runtime reflective machinery will absolutely suck. That's why Adobe invented the DescribeTypeCache class.