google apps script - Restrict notifications sent for changes referenced in columns -

i referenced this post make launch calendar dates , names:

the 2 columns have 1 date (a) , other launch name/description (b). in ideal state, wanted send notifications when:

• there new launch entry name (b); not date entered yet (a)
• separately, sending update date changes (a) , referencing launch name (b); there won't case have date no launch name (unless i'm in process of entering 1 after other), there should not notifications sent if there's date entered , no corresponding b cell yet.

i'm seeing false positives code in following ways:

1.) if don't enter date (a) put text in column (b), i'm getting date email empty referencing (b); i'd restrict not send notification if corresponding cell in column empty

2.) i'm getting duplicate date (a) emails; has adding date when second 'if' condition present check column b (launch name); it's when add new date, receive 2 emails adding date.

3.) if enter launch name (b) no date (a), i'm getting both emails; happening when second if condition present. preference not receive date email if date cell (a) empty.

i noticed deletion , empty cells seems send notification emails.

    function sendnotification() {   var ss = spreadsheetapp.getactivespreadsheet();   var sheet = ss.getactivesheet();   var cell = ss.getactivecell().geta1notation();   var row = sheet.getactiverange().getrow();   var cellvalue = ss.getactivecell().getvalue().tostring();   var mycell = ss.getactiveselection();   var cellcol = mycell.getcolumn();    var recipients = "me@me.com";   var message = '';   if(cell.indexof('a')!=-1){      message = sheet.getrange('b'+ sheet.getactivecell().getrowindex()).getvalue()   }   var subject = ':date modification  «' + message + '»';   var body = 'the launch tracker has been updated. \n\n\na date modification of: «' + cellvalue + '» has occured following user-facing change: «' + message + '» \n\n\nthis modification should reflected on launch calendar. \n\n\nvisit: ' + ss.geturl() + ' view modification, found in row: «' + row + '»';   mailapp.sendemail(recipients, subject, body);   if (cellcol == 2)   var subject = 'new addition of «' + cellvalue + '»';   var body = 'the waypoint tracker has been updated. \n\n\na new user-facing change of: «' + cellvalue + '» has been added. \n\n\nthis modification should reflected on launch calendar when date information added. \n\n\nvisit: ' + ss.geturl() + ' view modification, found in cell: «' + cell + '»';   mailapp.sendemail(recipients, subject, body); }