Cacher is the code snippet organizer for pro developers

1. Copy/Paste the information below to the clipboard
2. Open the spreadsheet whose sheets need to be alphabetised
3. Choose Tools > Script editor > Blank (this opens a new tab in the browser)
4. Press Control+A followed by Control+V copy and paste the script in
5. Press Control+S to save the script
6. Choose Run > sortSheets
7. Go back to the spreadsheet tab to view the new sorted tab order

--Copy everything below this line--
function sortSheets () {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheetNameArray = [];
  var sheets = ss.getSheets();
   
  for (var i = 0; i < sheets.length; i++) {
    sheetNameArray.push(sheets[i].getName());
  }
  
  sheetNameArray.sort();
    
  for( var j = 0; j < sheets.length; j++ ) {
    ss.setActiveSheet(ss.getSheetByName(sheetNameArray[j]));
    ss.moveActiveSheet(j + 1);
  }
}