How can I create a progress spinner using HtmlService?

Question

In scriptUi I was able to follow these instructions to create a simple progress spinner for long waits: https://sites.google.com/site/scriptsexamples/learn-by-example/uiapp-

Answer 1

I found a method. The trick was to call an internal function that both starts the spinner and runs the other function.

html

 Copy
 Close

gs file

function testSpinner(){
 SpreadsheetApp.getActiveSpreadsheet().toast("Copying...","",-1);
  Utilities.sleep(5000);
 SpreadsheetApp.getActiveSpreadsheet().toast("Done.");
}