I'm applying a function to map a calculation over a list of dates. In the old calculation I just manually entered each date and ran the code. As part of if that code I would use .get('year).getInfo() to obtain the year from a manually entered data.

var startDate = ee.Date('2016-10-01');
var endDate = ee.Date(startDate.advance(1,'month'));

var startyear = startDate.get('year').getInfo(); 
var endyear = startDate.get('year').getInfo();

I've tried do this again within my function

  var start = ee.Date(date);
  var end = ee.Date(date).advance(1,'month');
  var date_range = ee.DateRange(start,end);
  var startyear = start.get('year').getInfo(); 
  var endyear = start.start.get('year').getInfo();

But I'm getting the error Unknown variable references: [].

I'm guessing it's got something to do with the .getInfo function and client vs server side. However, to obtain year as an object for use, I need to use .getInfo to obtain it. Does anyone know any work arounds?

The link to my code is here

  • Why do you need to get the years with .getInfo()?
    – JonasV
    Feb 2, 2021 at 9:22
  • I have another line code further down that uses the year, var startdate = ee.Date.fromYMD(startyear, 1, 1); I could only get that to read the year using .getInfo. Are there other options? Feb 2, 2021 at 9:28

1 Answer 1


Your issue is in this line:

var enddate = ee.Date.fromYMD(endyear + 1 , 1 , 1);

because endyear is an ee.Number if you don't use .getInfo() you can not call +1 on it. Instead you need to use the Earth Engine specific functions:

var enddate = ee.Date.fromYMD(endyear.add(1) , 1 , 1);

If you do this, you can just remove the .getInfo() calls.

  • Thanks I thought it might be something simple. Greatly appreciated. Feb 2, 2021 at 9:54

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