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

Question

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

kglad · Accepted Answer

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.

wdesp · Answer

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 --

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

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