ResizeArtboardsToContents.jsx

#target Illustrator
//  script.name = ResizeArtboardsToContents.jsx;
//  script.description = resizes All artboards to the art present on themselves.
//  script.author= Herman van Boeijen, www.nimbling.com // 24/10/2013;

if ( app.documents.length > 0 ) {
            
    doc = app.activeDocument;
    
    if(!doc.saved){
        Window.alert("This script needs to modify your document. Please save it before running this script.");
    }

}else{
    Window.alert("You must open at least one document.");
}

function ResizeArtboardsToContents(doc){
    //Get total amount of groups
    var TotalArtboards = doc.artboards.length;

//iterate all Artboards
    for (var i = 0 ; i < TotalArtboards ; i++){
        var CurrentArtboard = doc.artboards[i];
        doc.artboards.setActiveArtboardIndex(i);
        //Select everything on artboard
        doc.selectObjectsOnActiveArtboard(i);
        //Resize artboard to selection
        doc.fitArtboardToSelectedArt(i);
        }
}

ResizeArtboardsToContents(doc);