How to fast copy PDF to ai file?

[LoveYou阿逗逼6666]

I just want to duplicate PDF contents into a new layer of an AI file? So how to fast copy? Now I have to open the PDF file and copy pageItems one by one:

var firstLayer = docSrc.activeLayer;
var newLayer = docDest.layers.add();
if (firstLayer.pageItems.length > 0) {
    for (var i = firstLayer.pageItems.length - 1; i >= 0; i--) {
        var item = firstLayer.pageItems[i];
        item.duplicate(newLayer, ElementPlacement.PLACEATBEGINNING);
    }
}

[femkeblanco]

Duplicating items one by one is the established and most consistent way. 

[Willi Adelberger]

Opening a PDF in Illustrator may desroy text and color profiles. Therefore do not open any PDF in Illustrator except those which are created and saved in Illustrator with its editing capabilities.

What you can do: Place a PDF file as linked file, do not embed them. So you can duplicate as any other object.

[LoveYou阿逗逼6666]

Could you give some sample code to place a PDF file as linked file.

[CarlosCanto]

how long does it take duplicating items one at a time? 

[LoveYou阿逗逼6666]

It's slow, about 9 - 10s.

[CarlosCanto]

10 seconds is slow, how many pageItems are you processing?

instead of copying each item you could duplicate the ActiveLayer for an instant gratification. Unfortunately there's no API to duplicate layers.

The good news is that you can record an Action to duplicate layers and play that action with a script using

app.doScript("Action Name", "Action Set Name");

[pixxxelschubser]

A one page pdf?
How about place and embed?

[Willi Adelberger]

Embedding is the same as opening a PDF. As PDFs can have different color spaces and profiles all will be converted or changed to the AI's color space and destroy the colors of the original PDF. 
Another problem are the fonts. If the original fonts are not installed some other font will be replaced and text blocks are destroyed and the text appearance might change,