AppsScript to copy doc if updated

copyDoc.js

//This script should be stored in Drive as a AppScript file and configured to run at intervals
//In my case, run it every two hours and copied the doc if there was an update

//ID of original document
var srcDocId="xxxxxx";
//ID of desitination Folder
var targetFolderId= "xxxxxx";

function copyDoc() {
	copyDocIfUpdated(srcDocId,targetFolderId,2);
}

/**
* src : file to poll
* dest : destination folder to create a copy
* intervalhours : how you would define fresh. 
*/
function copyDocIfUpdated(src,dest,intervalhours){
  
  var srcFile=DriveApp.getFileById(src);
  var lastupdated=srcFile.getLastUpdated();
  var now= new Date();
  if(((now.getTime()-lastupdated.getTime())/(1000*3600))<intervalhours){
    var targetFolder=DriveApp.getFolderById(dest);
    //Logger.log(file.getName());
    var datestr=Utilities.formatDate(new Date(), "Asia/Singapore", "YYYY/MM/dd HH:mm");
    var newFile=srcFile.makeCopy("[copy "+datestr+"] " + srcFile.getName(), targetFolder);
  }
}