Dealing with empty cells in Google Apps Script - google-apps-script

Question

Why doesn't this work?
function sendDuesReminder() {
var paid = 3;
var name = 1;
var submitted = 0;
var allowance = 9;
var ms = 86400000; // Number of milliseconds in a day
var today = new Date();
var reminder = 72;
var data = SpreadsheetApp.openById('___').getSheetByName('Master').getDataRange().getValues();
for (var i = 1; i < data.length; i++) {
if (data[i][paid] != 'Yes' &&
data[i][paid] != 'yes' &&
data[i][reminder] == '' &&
((((today.valueOf()) - (data[i][submitted].valueOf()))/ms) > allowance)) {
MailApp.sendEmail("___", "___") ;
SpreadsheetApp.openById('___').getSheetByName('Master').getRange(i+1, reminder).setValue(today);
}
if (data[i][paid] != 'Yes' &&
data[i][paid] != 'yes' &&
data[i][reminder] != null &&
((((today.valueOf()) - (data[i][reminder].valueOf()))/ms) > allowance)) {
MailApp.sendEmail("___", "___") ;
SpreadsheetApp.openById('___').getSheetByName('Master').getRange(i+1, reminder).setValue(today);
}
SpreadsheetApp.flush();
}
Browser.msgBox("OK. Reminder e-mails have been sent. !")
}
What I really want to do is say send the e-mail if column BT is empty OR if the date in column BT is older than 9 days. But I didn't know how to include an or statement within the if statement. So I just set up two separate if statements.
When I use '', though, for the second if statement, I get an error saying that it can't get the value of something that's undefined.
When I use null or undefined, it doesn't work.
Anybody have any thoughts?

Answer 1

Are you sure you have 72 columns in your spreadsheet ? when you use data[i][reminder] == '' the error returned concerns the first term of the equal, not the second... so I guess data doesn't have 72 secondary index and this is returning an error.
(EDIT : to be more clear : you cannot get the value of an undefined item using .valueOf and divide it by something, that's why you get "an error saying that it can't get the value of something that's undefined ".)
If you want to learn about how to implement OR statement you can have a look at w3school, 'Comparison Operators'
Note that you can compare date object directly, you don't need to convert them to milliseconds explicitely, javascript does it internally.
here is an example of how you could write this shortly
var tendaysBefore = new Date(new Date().getTime()-10*24*60*60*1000);// 10 days before
if (data[i][paid].toLowerCase() != 'yes' && (data[i][reminder] == ''||(data[i][reminder] == null || data[i][submitted]< tendaysBefore)) { // not 'yes' and one of the 3 other conditions
MailApp.sendEmail("___", "___") ;
SpreadsheetApp.openById('___').getSheetByName('Master').getRange(i+1, reminder).setValue(today);
}

Answer 2

So here's the code for the loop I tried based on Serge's very kind initial thought.
for (var i = 1; i < data.length; i++) {
if (data[i][paid].toLowerCase() != 'yes' &&
(data[i][submitted]<tendaysBefore &&
(data[i][reminder] == ''||
data[i][reminder] == null))) {
MailApp.sendEmail("___", "Reminder About Dues for Newcomers & Neighbors", "___") ;
SpreadsheetApp.openById('___').getSheetByName('Master').getRange(i+1, reminder).setValue(today);
}
SpreadsheetApp.flush();
}
I changed the order of the if statement because I'm not sure I've adequately articulated in English what I'm trying to get it to do.
What I WANT it to say is IF they haven't paid AND 10 days have passed since they submitted their form AND EITHER the reminder cell is blank or has a null value, THEN send the e-mail.
(Once I get THIS statement working, I'll go on to say if 10 days go by after we send the first e-mail and they STILL haven't paid, we send another e-mail. That's why I'm going through all this machination to put a date in reminder rather than just something like "sent".)
The code I have works. EXCEPT, if you run it, send out the first batch of e-mails, let it add today's date to reminder, and then run it again, it sends the e-mails out all over again.
In short,
(data[i][reminder] == ''||
data[i][reminder] == null))
doesn't seem to be accomplishing what is supposed to do, which is make the if statement fail for any row that has ANYTHING in the reminder column. That's why I initially came at this with "how do I deal with empty cells"? Because--for the life of me, I can't understand why
(data[i][reminder] == ''||
data[i][reminder] == null))
isn't bulletproof.
As I suggested in my comment to Serge's answer, this is starting to make me crazy. I, therefore, cannot thank anybody enough for ANY thoughts you have. Thanks in advance!
In response to Serge's question that I capture some values from the log, here's the output from the log after I added his requested code to the loop:
Paid=yes date subm=Sat Jun 02 2012 14:44:27 GMT-0400 (EDT)reminder=undefined
Paid=yes date subm=reminder=undefined
Paid=yes date subm=reminder=undefined
Paid=yes date subm=reminder=undefined
Paid=yes date subm=reminder=undefined
Paid=yes date subm=reminder=undefined
Paid=yes date subm=reminder=undefined
Paid=yes date subm=reminder=undefined
Paid=yes date subm=reminder=undefined
Paid=yes date subm=reminder=undefined
Paid=yes date subm=reminder=undefined
Paid=yes date subm=Wed Jun 27 2012 16:22:35 GMT-0400 (EDT)reminder=undefined
Paid=yes date subm=Fri Jun 29 2012 09:07:21 GMT-0400 (EDT)reminder=undefined
Paid=yes date subm=Mon Jul 09 2012 10:11:20 GMT-0400 (EDT)reminder=undefined
Paid=yes date subm=Mon Jul 09 2012 10:16:56 GMT-0400 (EDT)reminder=undefined
Paid= date subm=Mon Jul 09 2012 10:17:00 GMT-0400 (EDT)reminder=undefined
Paid=yes date subm=Mon Jul 09 2012 10:26:36 GMT-0400 (EDT)reminder=undefined
Paid=yes date subm=Mon Jul 09 2012 10:30:23 GMT-0400 (EDT)reminder=undefined
Paid=yes date subm=Mon Jul 09 2012 11:02:19 GMT-0400 (EDT)reminder=undefined
Paid= date subm=Mon Jul 09 2012 12:33:57 GMT-0400 (EDT)reminder=undefined
Paid=yes date subm=Mon Jul 09 2012 13:48:54 GMT-0400 (EDT)reminder=undefined
Paid= date subm=Mon Jul 09 2012 18:19:22 GMT-0400 (EDT)reminder=undefined
Paid= date subm=Mon Jul 09 2012 21:07:05 GMT-0400 (EDT)reminder=undefined
Paid= date subm=Mon Jul 09 2012 21:44:13 GMT-0400 (EDT)reminder=undefined
Paid= date subm=Mon Jul 09 2012 21:53:55 GMT-0400 (EDT)reminder=undefined
Paid= date subm=Tue Jul 10 2012 11:09:03 GMT-0400 (EDT)reminder=undefined
Paid= date subm=Tue Jul 10 2012 12:57:41 GMT-0400 (EDT)reminder=undefined
Paid=yes date subm=Wed Jul 11 2012 18:36:49 GMT-0400 (EDT)reminder=undefined
Paid= date subm=Thu Jul 12 2012 07:14:53 GMT-0400 (EDT)reminder=undefined
Paid=yes date subm=Tue Jul 17 2012 14:54:16 GMT-0400 (EDT)reminder=undefined
Paid=yes date subm=Wed Jul 18 2012 20:26:23 GMT-0400 (EDT)reminder=undefined
Paid= date subm=Thu Jul 19 2012 13:43:09 GMT-0400 (EDT)reminder=undefined
I have no idea what to make of this, but I'm sure smarter people than I do see something interesting here?
OK, following Serge's diligent trouble shooting with me, here's the code that worked for this problem. Many, MANY thanks to Serge!
function sendDuesReminder() {
var paid = 3;
var name = 1;
var submitted = 0;
var allowance = 9;
var ms = 86400000; // Number of milliseconds in a day
var today = new Date();
var reminder = 72;
var reminderArray = reminder - 1;
var tendaysBefore = new Date(new Date().getTime()-10*24*60*60*1000);
var data = SpreadsheetApp.openById('___').getSheetByName('Master').getDataRange().getValues();
for (var i = 1; i < data.length; i++) {
if (data[i][paid].toLowerCase() != 'yes' &&
(data[i][submitted]<tendaysBefore &&
(data[i][reminderArray] == ''||
data[i][reminderArray] == null))) {
MailApp.sendEmail("___", "___", "___") ;
SpreadsheetApp.openById('___').getSheetByName('Master').getRange(i+1, reminder).setValue(today);
}
SpreadsheetApp.flush();
Logger.log('Paid='+data[i][paid].toLowerCase()+' date subm='+data[i][submitted]+'reminder='+data[i][reminder])
}
Browser.msgBox("OK. Reminder e-mails have been sent. !")
}