Hi am relativly new to indesign scripting and would like to figure out if an object is a subtype of a class. Example: I want to iterate over all page items and take everything that is not a graphic:
layer = app.activeDocument.layers[layerIndex];
for (i = 0; i < layer.allPageItems.length; i++) {
alert(layer.allPageItems[i].reflect.name)
if(layer.allPageItems[i].isPrototypeOf (Graphic) ) {
alert("Graphic");
} else {
....
}
}
howver the if nver matches. Are there any examples of how to use isPrototypeOf
? What do I have to do to test if an object is of a certain type or a subclass of it?
edit : To clarify, I am trying to test if I have an Instance of anything that inherited from Graphic.
But as far as I can see now that seems to be impossible.
You probably want the instanceof operator.
if (layer.allPageItems[i] instanceof Graphic) {
alert("Graphic");
} else {
....
}
You could also use isPrototypeOf
but you have to reverse the order and get the prototype itself, not the constructor. So it would look like this:
if (Graphic.prototype.isPrototypeOf(layer.allPageItems[i])) {
alert("Graphic");
} else {
....
}
You can get access to the essence of the pageItem by calling the getElements() method. It returns an array of the original material. Given a rectangle on a page (nothing else) :
app.activeDocument.allPageItems[0].getElements()[0] instanceof Rectangle //true;
Are you sure its not supposed to be
Graphic.isPrototypeOf(layer.allPageItems[i])
or something like
Graphic.prototype.isPrototypeOf(layer.allPageItems[i])
?
Your current version sounds like its backwards.
Apparently this is not possible, I also asked on the adobe Forums with this result: http://forums.adobe.com/message/4461211#4461211
So the short answer is, I have no way to check if I hold an object wich is an instace of someClass
or a child thereof. Neither reflection nor isPrototypeOf
help.
I might try casting in a try catch block but consider this as ugly. Thus I will go with the solution suggested on the adobe Forums, test for all possible heirs (children/classes inherting from base) and the base class. This is ugly and lengthy but I have not found a better solution.
edit : here is an exceprt from one of adobes examples, it allows for the switch syntax avoidng an endless if construct:
switch (app.selection[myCounter].constructor.name){
case "Rectangle":
case "Oval":
case "Polygon":
case "GraphicLine":
case "TextFrame":
myObjectList.push(app.selection[myCounter]);
break;
}
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