AS3: Checking if a variable is of the Object type

Question

I want to do something like this in Actionscript 3:

if(variable is Object) ...;
else ...;

Where variable could be a String(), Number(), Array(), Object()...

Currently the above check returns true for all of these types, which makes sense. I only want it to return true for objects made with new Object(), however.

Any help would be much appreciated!

Answer 1

You should try to use this functions - getQualifiedClassName and typeof. Here's a code showing how they behave for different data types you've listed, see the difference for the Array and Numbers especially:

Code:

var o = new Array();                
trace ("var o = new Array()");
trace (getQualifiedClassName(o));
trace (typeof(o));      
var o = new Object();   
trace ("var o = new Object();");
trace (getQualifiedClassName(o));
trace (typeof(o));
var o = new String();
trace ("var o = new String()");
trace (getQualifiedClassName(o));
trace (typeof(o));
var o = new Number()
trace ("var o = new Number()");
trace (getQualifiedClassName(o));
trace (typeof(o));              
var o = 3.14;
trace ("var o = 3.14");
trace (getQualifiedClassName(o));
trace (typeof(o));

Result:

var o = new Array()
Array
object
var o = new Object();
Object
object
var o = new String()
String
string
var o = new Number()
int
number
var o = 3.14
Number
number

I assume getQualifiedClassName would be what you're looking for, which is in the flash utils package:

import flash.utils.getQualifiedClassName;

Answer 2

Try something based around one of these:

if (variable.constructor.toString().match(/object/i) == 'Object')

if (variable.constructor.toString().indexOf("Object") != -1)

If the object is an Object() the constructor string will be something like

function Object() { ... }

so you can check for that.

Answer 3

You can also use getQualifiedSuperclassName which returns null for the Object type as it doesn't have a super class:

public static function isObject( obj:* ):Boolean
{
    if ( obj == null )
        return false;
    return ( getQualifiedSuperclassName( obj ) == null );
}