What's the difference between String() - as String - toString();

[Venian]

Hello,

I'm wondering what's the difference between this 3 ways of getting around.

[kglad · Accepted solution]

there's zero difference between casting an object as a string using:

String(something)

and

something as String.

if you can use one of the above on the same object that you're applying the toString() method to, there will be no difference among the 3.

[Venian]

I see, but if instead of string there's MyClass or MovieClip...

[kglad]

if there's a difference between the two classes, MyClass and MovieClip, then there might be a difference when casting.

[wdesp]

There is a great difference between String(), as String and toString() methods.

String(param) -- the more general and safe method.

• Returns "null" (string!) if param is null;
• Returns result of param.toString() method if it is defined in class;
• Returns string representation of the param (returns "[object Object]" if param is Object);

param asString --

• Returns string if param is a type of String;
• Returns null otherway (if param is custom class, int or other type);

param.toString() -- call of toString() member function

• throws an exception if param is null;
• compile-time error if toString() method is not defined in param (if your custom class do not have or inherits this function);
• returns result of toString() function

Exists also ""+param and param+"" ways. They are similar to ""+String(param) and String(param)+""

Pay attention:

var ss:String = null;

trace(String(ss)==(ss as String)); // Returns false as "null" not equal to null