Problem converting Strings into dates in a multidimensional array in javascript (GAS)

Question

In order to automate some daily processes I am reading data from a google sheet and putting them into a dictionary. From said dictionary the data is then written into other sheets. It all works like a charm apart from one little bug that I do not understand:

I get all the data from the sheet and put it into a dictionary like so:

  var data = sheetImp.getRange(1,1, sheetImp.getLastRow(), sheetImp.getLastColumn()).getValues();
  var bib_tis = {};
  for (var i = 0; i < data.length; i++) {
    var date = new Date(data[i][0]);
    date.setHours(0, 0, 0, 0);
    if (date.valueOf() == yesterday.valueOf()) {
      var key = data[i][4] + ' ' + data[i][2]
      bib_tis[key.trim()] = data[i][5];    
    }
  }

I check if date is yesterday because I only need that data. The dictionary contains all lines but the very first one. To check that I did the following in order to debug:

  Logger.log(typeof(data[0][0]));    // string
  Logger.log(data[0][0].valueOf());  // 2019-11-12T00:00:00+01:00
  Logger.log(data[0][0]);            // 2019-11-12T00:00:00+01:00
  Logger.log(new Date(data[0][0]));  // Thu Jan 01 01:00:00 GMT+01:00 1970
  Logger.log(typeof(data[1][0]));    // string
  Logger.log(data[1][0].valueOf());  // 2019-11-12T00:00:00+01:00
  Logger.log(data[1][0]);            // 2019-11-12T00:00:00+01:00
  Logger.log(new Date(data[1][0]));  // Tue Nov 12 00:00:00 GMT+01:00 2019

Why does the first date not convert correctly?

I could try to work the other way around and convert yesterday to a string and compare strings but I do not understand why this doesn't work for the first line in the array?

Kind regards Jan

Michael Beeson · Accepted Answer · 2019-11-13 12:36:13Z

1

You have fallen foul of an invisible utf character: U+FEFF

Try copying the output of your logs, and paste them into a hidden character revealer, for example:

https://www.soscisurvey.de/tools/view-chars.php

You'll see that for the first date you have U+FEFF at the start of the date (but not for the second date).

Here's a blog about that character, aka ZERO WIDTH NO-BREAK SPACE:

https://www.freecodecamp.org/news/a-quick-tale-about-feff-the-invisible-character-cd25cd4630e7/

Now you can try stripping that character away, or look into why it's being prepended to that date. It has something to do with utf16 encoding.

Good luck!

answered Nov 13, 2019 at 12:36

Michael Beeson

2,8632 gold badges20 silver badges26 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Jan Peters Over a year ago

Thank you so much, that was indeed the problem and thus a simple trim() in my for loop solved this one. Everyday is a school day I guess.

Collectives™ on Stack Overflow

Problem converting Strings into dates in a multidimensional array in javascript (GAS)

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related