how to duplicate frame content to another frame

… I thought there is faster method than use of copy() and pasteInto()

Without adding something, that is not inside the source graphic frame?
Like a group object or a text frame one can anchor something to?
Unfortunately no.

Otherwise you have to sample all possible properties with their respected values of the target object, do a duplicate of the source and apply the stored values to the duplicate. Plus remove the original target.

But that would remove assumed unique properties like the id number of the object from all the id numbers of all objects in the document, would remove "private" data set by insertLabel() and 3rd party plugIns that is hard or impossible to gather…

Regards,
Uwe

Here an example with two selected objects.

The blue one is the source and contains a rectangle, the target is the yellow circle.

That's for InDesign CS5.5 or above since I am working with the order of selection with the code below.
First I selected the source, then I added the target to the selection by holding the SHIFT key and selected the target.

The script will use the mentioned app methods that work on selections.

Before:

After running the script:

Script:

You can undo the actions in one go.

Read the code, read the comments.

Note:

If the target contains anything it will be replaced by the duplicated contents of the source.
Without warning!

function main()
{
    // Minimum check, there could be way more:
    // Do nothing, if not two objects are selected:
    if(app.selection.length != 2){return};
   
    // The first selected object is the source:
    var source = app.selection[0];
   
    // Do nothing, if the source contains no object(s):
    if(source.pageItems.length == 0){return};
   
    // The second selected object,
    // that is added to the first selected one
    // is the target:
    var target = app.selection[1];
   
    // Duplicate the object inside the source
    // That would free it from the source
    var contents = source.pageItems[0];
    var dupContents = contents.duplicate();
    app.select(dupContents);
    app.cut();
    app.select(target);
    app.pasteInto();
    app.select([source,target]);
   
    // If you want to remove the object inside the source
    // do it now:
    // contents.remove();
};
app.scriptPreferences.userInteractionLevel = UserInteractionLevels.interactWithAll;
app.doScript
    (
   
    main,
    ScriptLanguage.JAVASCRIPT,
    [],
    UndoModes.ENTIRE_SCRIPT,
    "Paste Into Target | SCRIPT"
   
    );

Regards,
Uwe