在对象中找不到函数setFullYear-Google脚本

Question

Very new to scripting. This is my second script, I basically modified a Google Sample.

Error I'm getting: TypeError: Cannot find function setFullYear in object . (line 22, file "Code").

Script does seems to complete, as emails get sent, but I'd like to know why I'm getting the error, and what can I do to correct it.
I'm assuming the script doesn't like the date format.

Problematic code:
var dateToSend = row[0]; dateToSend = dateToSend.setFullYear(0000);

row[0] refers to a cell on a Google Sheet with a date in it.

Full script, if it helps:

var today = new Date() 
today.setHours(0,0,0,0) 
today = today.setFullYear(0000) // Set year as 0, so recurs every year


var EMAIL_SENT = "EMAIL_SENT";

function sendEmailsByDate() {
  var sheet = SpreadsheetApp.getActiveSheet();
  var dataRange = sheet.getRange('A2:E')
  var data = dataRange.getValues();
  for (var i = 0; i < data.length; ++i) {
    var row = data[i];
    var dateToSend = row[0];  
    dateToSend = dateToSend.setFullYear(0000); // This is the problematic line 22
    var emailAddress = row[1];                  
    var subject = row[2];                   
    var message = row[3];                     
    var emailSent = row[4];                     
    if ((emailSent != EMAIL_SENT) && (today == dateToSend)) {  
      MailApp.sendEmail(emailAddress, subject, message);
      sheet.getRange(startRow + i, 5).setValue(EMAIL_SENT);
      SpreadsheetApp.flush();

    }
  }
}

Answer 1

You have to create a date object with the row[0] data so that you can access the setFullYear function on it. Like so:

  for (var i = 0; i < data.length; ++i) {
    var row = data[i];
    var dateToSend = new Date(row[0]);