Log Email in GAS

LogEmail.js

function logIncomingEmails() {
 
  var EmailLog = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Email Log")
  var rows = EmailLog.getDataRange();
  var numEmailRows = rows.getNumRows();
  
  var Unlogged = GmailApp.getUserLabelByName("Unlogged")
  var Logged = GmailApp.getUserLabelByName("Logged")
  var UnloggedThreads = Unlogged.getThreads(0,50);   // Returns an array of the first 50 unlogged threads. Hopefully there won't be more than 50 per minute!
  
  var IssueLog = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Issue Log");
  var IssueRows = IssueLog.getDataRange();
  var NumIssueRows = IssueRows.getNumRows();  
  
for( var i = 0; i < UnloggedThreads.length; ++i ) {
  
  var ThreadMessages = UnloggedThreads[i].getMessages();
  var from = ThreadMessages[ThreadMessages.length - 1].getFrom(); 
  var subject = UnloggedThreads[i].getFirstMessageSubject();
  var body = ThreadMessages[ThreadMessages.length - 1].getBody();  //.replace(/<([A-Z][A-Z0-9]*)\b[^>]*>(.*?)<\/\1>/g,""); 
  var NewBody = RemoveHTML(body);
  var updated = UnloggedThreads[i].getLastMessageDate()
  var ref = (subject.indexOf("Ref:") != -1) ? subject.slice(subject.indexOf("Ref:")+4,subject.indexOf("Ref:")+11) : "";
 
  EmailLog.getRange("A" + (numEmailRows + 1)).setValue(from);  
  EmailLog.getRange("B" + (numEmailRows + 1)).setValue(subject);
  EmailLog.getRange("C" + (numEmailRows + 1)).setValue(updated);
  EmailLog.getRange("D" + (numEmailRows + 1)).setValue(ref);
  
  UnloggedThreads[i].removeLabel(Unlogged);
  UnloggedThreads[i].addLabel(Logged);
     
  if(ref.length != 0){
     var IssueProperties = DefineIssueProperties(ref,IssueLog,NumIssueRows);
         
       if(IssueProperties["Type"] == "Old"){
         
           //EmailLog.getRange("E" + (numEmailRows + 1)).setValue(IssueProperties["OldIssueSheetID"]);
           UpdateIssueHistorySheet(updated,NewBody,ref,IssueProperties["OldIssueSheetID"],IssueLog,NumIssueRows,false);
           
         }
    
     numEmailRows++; 
      
    }

  }   

}  




function RemoveHTML(body){
var NewBody = body;                                      // Set new string equal to old string
    for(var j = 0; j < body.length; j++){
      if(body.charAt(j) == "<"){
        var OPos = j;                                    // find tag opening in old string 
      } else if(body.charAt(j) == ">"){
        var CPos = j;                                    // find tag closing in old string
        var HTML = body.slice(OPos,CPos+1);              // HTMl tag to be removed - note, created from old string
        var NewBody = NewBody.replace(HTML,"");          // Remove HTML tag from new string
      }    
    }
  return NewBody;                                        // Return new HTML-free string
}