Google Apps Script date format issue (Utilities.formatDate)

Question

I am pretty new to Google Apps Script, so please bear with me.

I am collecting daily interest rates from a bank on Google Sheets, and I am using the following code to append new rows for the rates contained in A5:F5, with column A containing dates.

function recordHistory() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getSheetByName("Interest Rates");
  var source = sheet.getRange("A5:F5");
  var values = source.getValues();
  values[0][0] = Utilities.formatDate(new Date(), "GMT+10:00", "yyyy-MM-dd");
  sheet.appendRow(values[0]);

};

My issue is this - although I have specified the date format to be "yyyy-MM-dd" the dates in column A in my new rows are created in this format "M/dd/yyyy".

I have tried pre-formatting entire column A with "yyyy-MM-dd" using the drop down Format menu in Google Sheets, but if I run the code above my new row is still in "M/dd/yyyy".

It's as if my code ignores Utilities.formatDate completely. FYI I got the above code from here.

Answer 1

The Utilities.formatDate() utility formats a javascript String. However, when written out to the spreadsheet, the new row of data is interpreted by Google Sheets to determine data types and appropriate formatting, just as if you'd typed it in through the user interface.

Since you've got a recognizable date string, Google Sheets decides it's a Date, stores it as such, and applies the default date format.

You've got two options for making the date in the spreadsheet meet your formatting needs.

1. Force it to be interpreted as a String, even if it does look like a date.

   cell.setValue(Utilities.formatDate(new Date(), "GMT+10:00", "''yyyy-MM-dd"));
   //                                                           ^^ force string literal
   

2. Set the date format for the cell. This will leave the value of the cell as a date, which is useful for calculations.

   Date formats follow the SimpleDateFormat specification.

   // Cell A1 contains a date
   var cell = SpreadsheetApp.getActiveSheet().getRange("A1");
   cell.setNumberFormat('yyyy-mm-dd');
   

Answer 2

Solution :

values[0][0] = Utilities.formatDate(new Date(), 
"GMT+10:00", "yyyy-MM-dd").setNumberFormat('yyyy-mm-dd');