Google Script test for file existance
<p>I can't believe there isn't a simple way to do this, but I've trawled everywhere for a working solution without success.</p>

<p>I am running a Google script in a Google Sheet and I'm at a point in the code where I want to save the spreadsheet as a new filename. Before I do that I want to check that there isn't already one in existence (because I don't want to overwrite it).</p>

<p>The code below that I'm using to test returns "File Exists" regardless of whether the folder or the file exists or not.</p>

<p>As always, any help much appreciated:-)</p>

<p>Here's my test code.</p>

<pre><code>function testscriptforfileexistance() {
  filecheck = checkfileexists("UnderDevelopment",'20160919 Weekly Roster v1.0.gsheet');

  if (filecheck.filefound = true)  {
    Browser.msgBox("file found") ;
  } else {
    Browser.msgBox("File not found");
  }
}


function checkfileexists(foldername,fn) {
  var destFolder = DriveApp.getFoldersByName(foldername);
  filefound=false;
  var destFileId = DriveApp.getFilesByName(fn);
//if hasnext returns false, presumably it doesn't exist
  if (!destFileId.hasNext) {
    Logger.log ("Found");
    filefound = true;
// and as a second test, if the length is zero the file doesn't exist
  if (!destFileId[0]) {
    Logger.log ("zero length");
    filefound=false;
  }
  }
  return {filefound:filefound};
}
</code></pre>

<p>Cheers
...Steve</p>