ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Using native JSON functionality
MovieClip.prototype.toJSON = function(k):* {
trace("prototype.toJSON() called.");
return "toJSON";
}
When your application then calls stringify() on any MovieClip instance, stringify() returns the output of your
toJSON() method:
var mc:MovieClip = new MovieClip();
var js:String = JSON.stringify(mc); //"prototype toJSON() called."
trace("js: " + js); //"js: toJSON"
You can also override toJSON() in native classes that define the method. For example, the following code overrides
Date.toJSON():
Date.prototype.toJSON = function (k):* {
return "any date format you like via toJSON: "+
"this.time:"+this.time + " this.hours:"+this.hours;
}
var dt:Date = new Date();
trace(JSON.stringify(dt));
// "any date format you like via toJSON: this.time:1317244361947 this.hours:14"
Defining or overriding toJSON() at the class level
Applications aren't always required to use prototypes to redefine toJSON(). You can also define toJSON() as a
member of a subclass if the parent class is not marked final. For example, you can extend the ByteArray class and define
a public toJSON() function:
package {
}
import flash.utils.ByteArray;
public class MyByteArray extends ByteArray
{
public function MyByteArray() {
}
}
public function toJSON(s:String):*
{
return "MyByteArray";
}
var ba:ByteArray = new ByteArray();
trace(JSON.stringify(ba)); //"ByteArray"
var mba:MyByteArray = new MyByteArray(); //"MyByteArray"
trace(JSON.stringify(mba)); //"MyByteArray"
If a class is dynamic, you can add a toJSON property to an object of that class and assign a function to it as follows:
var d:Dictionary = new Dictionary();
trace(JSON.stringify((d))); // "Dictionary"
d.toJSON = function(){return {c : "toJSON override."};} // overrides existing function
trace(JSON.stringify((d))); // {"c":"toJSON override."}
Last updated 6/6/2012
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