Google UI Apps Script: Blank PDF when converting spreadsheet to PDF - pdf

Question

I have a piece of code I am testing, in an attempt to learn how to convert a spreadsheet into a pdf using Google UI Apps Script. The code creates and writes to the spreadsheet but the pdf attachment is blank. Would appreciate any help to get this to work. Thanks.
var newSpreadsheet = SpreadsheetApp.create("My Test Sheet");
var columnNames = ["First Name", "Last Name", "Department"];
newSpreadsheet.getSheetByName('Sheet1').activate();
var headersRange = newSpreadsheet.getActiveSheet().getRange(1, 1, 1, columnNames.length);
headersRange.setValues([columnNames]);
var pdf = DocsList.getFileById(newSpreadsheet.getId()).getAs('application/pdf').getBytes();
var attach = {fileName:'My Test PDF.pdf',content:pdf, mimeType:'application/pdf'};
// Send email
MailApp.sendEmail("myemail#email.com", "subject", "message", {attachments:[attach]});

Answer 1

You should not use DocList anymore. Use DriveApp instead. Below a solution with little modifications of your code:
function toPdf(id){
SpreadsheetApp.flush();
// var ssDoc = DriveApp.getFileById(SpreadsheetApp.getActiveSpreadsheet().getId());
var ssDoc = DriveApp.getFileById(id);
var pdf = DriveApp.createFile(ssDoc.getAs(MimeType.PDF));
return pdf.getBlob().getBytes();
}
function user2943227(){
var newSpreadsheet = SpreadsheetApp.create("My Test Sheet");
var columnNames = ["First Name", "Last Name", "Department"];
// newSpreadsheet.getSheetByName('Sheet1').activate();
var headersRange = newSpreadsheet.getActiveSheet().getRange(1, 1, 1, columnNames.length);
headersRange.setValues([columnNames]);
// var pdf = DocsList.getFileById(newSpreadsheet.getId()).getAs('application/pdf').getBytes();
var pdf = toPdf(newSpreadsheet.getId());
var attach = {fileName:'My Test PDF.pdf',content:pdf, mimeType:'application/pdf'};
// Send email
MailApp.sendEmail("myemail#email.com", "subject", "message", {attachments:[attach]});
}