Comparing Dates on Google Sheets with Google Apps Scripts is Returning Inaccurate Boolean Values

Question

My Google Sheets spreadsheet has a list of appointments that I am trying to compare with tomorrow's date (so that I can send a reminder the day before). My current code is returning true on certain dates that aren't on the spreadsheet. We have no appointments on Sundays and I am currently testing this on a Saturday but still receiving some true values. I searched the spreadsheet thoroughly for a possible booking mistake but there are none. I did notice, however, that when it looks for the date 4:24:2016 (which is tomorrow) it will return true on 4:14:2016 dates. I am pretty much stumped at this point.

function myFunction() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Sheet1');
  var apptDates = sheet.getRange(2, 32, sheet.getLastRow() - 1, 1).getValues();

  for (var i = 0; i <= apptDates.length; i++) {
    var apptDate = new Date(apptDates[i][0]);
    apptDate = apptDate.addHours(74);

    function dayAway(date, day) {
      return new Date(date.getTime() + day * (24 * 3600 * 1000));
    }
    Logger.log(apptDate >= dayAway(new Date(), 1));
  }
}

Answer 1

When you use new Date() you get a full JS Date object with not only day, month and year but also hours minutes, seconds and milliseconds .

That's why your comparison could not give results. Simply set the unneeded values to 0 and it will work. I used getTime() to compare milliseconds but could have used toString() as well, only the date objects are not suitable to check equality.

The Logger is a great help to debug such things.

code :

function myFunction() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Sheet1');
  var apptDates = sheet.getRange(2,6, sheet.getLastRow() - 1, 1).getValues();
  for (var i = 0; i < apptDates.length; i++) {
    var apptDate = new Date(apptDates[i][0]);
    Logger.log(apptDate.getTime()+'  ==?  '+dayAway(new Date(new Date().setHours(0,0,0,0)), 1).getTime());
    Logger.log(apptDate.getTime() == dayAway(new Date(new Date().setHours(0,0,0,0)), 1).getTime());
  }
}

function dayAway(date, day) {
  return new Date(date.getTime() + day * 24 * 3600 * 1000);
}