Export all items in INDESIGN file as individual PNG files

gistfile1.txt

// Set resolution options
  var rp = [72,150,300];

// Set EXPORT presets
    app.pngExportPreferences.exportResolution = 72;
    app.pngExportPreferences.antiAlias = true;
    app.pngExportPreferences.pngQuality = PNGQualityEnum.MAXIMUM;
    app.pngExportPreferences.pngColorSpace = PNGColorSpaceEnum.RGB;
    app.pngExportPreferences.pngExportRange = PNGExportRangeEnum.EXPORT_RANGE;

// Resolution Select Dialog
  var w;    
  w = new Window('dialog', 'Export Presets');  
  w.orientation = 'row';
  with (w) 
    {
	   w.sText = add('statictext', undefined, 'Select Export Resolution:');
	   w.dropdown = add ( 'DropDownList',undefined,undefined,{items:rp});
	   w.btnOK = add('button', undefined, 'OK');
    };
  w.dropdown.selection=0; 
  w.show();  
  
  // Set resolution
	  var x = 0;
	  x = x + w.dropdown.selection;
    app.pngExportPreferences.exportResolution = rp[x];

// SElECT Folder locations
  var myFileAmount = 0; 
  var myFileLocation = Folder.selectDialog("Please select path of InDesign Files");
  myFolder = new Folder ([myFileLocation]);
  myFolderContents = myFolder.getFiles("*.indd"); // array
  myFileAmount = (myFolderContents.length - 1); 

  // CHECK IF FILES IN FOLDER
    if (myFileAmount < 0){alert("No Files in selected folder");}
    else
      {
        var mySaveLocation = Folder.selectDialog("Please select path to Save PNG");
        mySaveFolder = new Folder ([mySaveLocation]);

      // OPEN FILES One at a time
      for (i = myFileAmount; i >= 0; i--)
        { 
          app.open(File (myFolderContents[i]));
          app.scriptPreferences.userInteractionLevel = UserInteractionLevels.NEVER_INTERACT;
          
          // SET Active Document
          var myDoc = app.activeDocument;

		      // EXPORT

          //One Page at a time
          for (var p=0; p < myDoc.pages.length; p++)
            {//page loop
             var pname = myDoc.pages.item(p).name; 
      
             //set all items in file hiden
             for (var itemnum=0;itemnum < myDoc.pages.item(p).pageItems.length; itemnum++)
              {
                myDoc.pages.item(p).pageItems.item(itemnum).visible = false;
              }

             // set page to export
             app.pngExportPreferences.pageString = pname;
      
             //add a 0 in from on less than 10
             if (p<9){var pnm=0;}else{var pnm=""}
      
              //LOOP Through items Set Visibility, export a PNG, Set Visibility
             for (var itemexport=0;itemexport < myDoc.pages.item(p).pageItems.length; itemexport++)
               {
                var itm = itemexport+1;//items start at 1 not 0
                myDoc.pages.item(p).pageItems.item(itemexport).visible = true;
                //ACTUALLY EXPORTING
                app.activeDocument.exportFile(
                 ExportFormat.PNG_FORMAT, 
                File(mySaveFolder.fsName + "/" + app.activeDocument.name.split(".indd")[0]  + "_"+ pnm + pname + "_" + itm +".png"),
                false, 
                   );
                //SET VISIBILITY
                myDoc.pages.item(p).pageItems.item(itemexport).visible = false;
        }  
      }
      
       app.activeDocument.close(SaveOptions.no);
    }
}