New Google Sheets custom functions sometimes display “Loading…” indefinitely

Question

SPECIFIC FOR: \"NEW\" google sheets only.

This is a known issue as highlighted by google in the new sheets.

Issues: If you write complex^* custom f

Answer 1

I ran up to a similar problem with importrange from another spreadsheet.

Actually in the spreadsheet you should get something like "Permission to access" the spreadsheet you approach with importrange But it got stuck forever in this and all tips like clearing cache etc. didn't worked.

Eventually I duplicated the spreadsheet and in this new spreadsheet it asked for the permission and all works fine now.

So it might help to duplicate your spreadsheet.

Answer 2

Add-ons

I had two add-ons, and no function was loading.

I removed them, and all is well!

Answer 3

I also had the problem that you explained. It seems that it can be caused in more than one way.

I ended up finding that my custom function was displaying that error because it relied on data from an =IMPORTRANGE() call, and that call was failing.

I eventually found that the =IMPORTRANGE() call was failing because I had forgotten to update the URL that it was importing from when I had uploaded a new version of that imported-from sheet. It seems that trying to IMPORTRANGE from a trashed file can cause the infinite "Loading..." error.

Answer 4

One cause: Permissions needing authorizing.

As far as {this problem, better phrased the cell result(s) of a custom function displaying the disgustingly-vague message ‘Loading... Error: loading data...’}, indeed in the case where all instances of the same/similar custom function call displaying this error, is that Google Sheets needs permissions to run the script (often additionally: meaning in the past it didn't need these), so instead of {acting appropriately: then prompting the user for these permissions else returning that error}, Sheets instead hangs with this disgustingly vague error.

Additional permissions can be needed from 1 or more:

1. Google App Scripts has since rewriting their permission structure --how this problem now just happened to me, per my internal note O80U3Z.
2. Your code or some library it uses made changes to require more access ...but in this case you have a much better chance of guessing the cause of this disgustingly-vague error, so hopefully won't be reading here.

To fix, I explicitly ran my GAS spreadsheet code by both: clicking one of my custom menu functions and, in the ‘script editor’, running one of my custom JS functions notably the ‘onOpen()’ since that is most comprehensive. The first promoted me for indeed new permissions, via popup ‘Authorization Required
The application "MM6ZBT(MM6Z83 script)" needs authorization to run.’, though onOpen() also did this in cases of GAS revising its permissions since we used that sheet. Then, as I was still getting this ‘Loading...’ error, I reloaded the web page (so the sheet), and, at least for these cases of this disgustingly vague error, it was gone and the computations worked fine :-)

Answer 5

Important Tip: Create multiple copies of your entire spreadsheet as you experiment. I have had 3 google spreadsheets corrupted and rendered completely in-accessible (stuck in a refresh loop). This has happened when I was experimenting with custom functions so YOU HAVE BEEN WARNED!

You will want to try one or many of the following ways to fix this issue:

1. As suggested by google, try re-loading the spreadsheet or re-naming the function or changing the parameters in the cell to see if this fixes the issue.

2. Surround ALL your custom functions in a try-catch block. This will help detect code issues you may not have tested properly. Eg:

   try{ //methods }catch(ex){ return "Exception:"+ex; }

3. Revert to the old sheets and test your functions and check for any other type of error such as an infinite loop or invalid data format. If the function does not work in the old sheets, it will not work in the new sheets and it will be more difficult to debug.

4. Ensure NONE of your parameters refer to, can expect to or will ever contain a number larger than 1 million (1000000). No idea why but using a number larger than a million as any parameter will cause your function to fail to execute. If you have to, ask the input to be reduced in size (maybe divide by 1000 or ask for M instead of mm).

5. Check for numeric or floating point issues where numbers may exceed a normal set of significant figures. The new sheets seems to be a little glitchy with numbers so if you are expecting very large or very complex numbers, your functions may not work.

Finally, if none of the above work, switch to the old google sheets and continue working. If you find any other limitations or causes for functions to fail to execute, please write them below for me and other users who are heavy g-sheet users!

Answer 6

FWIW, I just ran into this and the culprit ended up being a getRange() call that pulled several thousand rows into an array. Periodically it would get hung on the "Loading..." message.

I worked around it by putting that range into the document cache. It's a little kludgy because the cache only stores strings, not arrays, but you can force it back into an array using .split(',') when you need to access the array.

(In my case it's a single array. There's probably a way to do it using a double array, either by sending each row or column into its own cache, or reading the cache value back N items at a time, each N becoming its own array.)

Here's the relevant bit from my code:

var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("mySheet"); //search the "mySheet" sheet
// is the big list already in the cache?
var cache = CacheService.getDocumentCache();
var cached = cache.get("columnValues");
if (cached != null) {
   var columnValues = cached.split(','); // take the cached string and make it an array
} else { // it's not in the cache, so put it there
  var column = 1; // the column with your index
  var columnValues = sheet.getRange(2, column, sheet.getLastRow()).getValues(); // first row is header
  cache.put("columnValues",columnValues,60000); // this forces the array into a string as if you used .join() on it
}

This is definitely a bug in Apps Script -- getRange() shouldn't hang without a timeout or error message. But at least there's a workaround. Here's the bug I opened against it, where I've also put the full code.gs from my sheet.