Difference between "Object(meuobjeto)" and "(meuobjeto as Object)"?

Question

I wish I knew the difference between using Object(meuobjeto) and (meuobjeto as Object) based on the code below:

var mc:MovieClip = new MovieClip(); //Um objeto MovieClip

trace(mc as String); //null
trace(mc as MovieClip); //[object MovieClip]
trace(mc as Number); //null

trace(String(mc)); //[object MovieClip]
trace(MovieClip(mc)); //[object MovieClip]
trace(Number(mc)); //NaN

I always use the operator as, however, only to show the Intellisense with the functions of my object and make the writing of the code a little easier. But after all, what is the difference between the two? It is right that I use it in this way?

Answer 1

The difference between the two ways to accomplish the cast is in result when operation fails:

• Using as

  trace(mc as MovieClip);
  

  Will assign null in cases where the conversion fails.

• Involved in Type()

  trace(MovieClip(mc));
  

  Will generate a TypeError if the conversion fails.

Personally, the first option via as is preferable because we always have null to deal with...

---

^{Adapted to English by reply given on SOEN by the user @Marty.}