Issue matching argument in google script - google-apps-script

Question

I am new to scripting, and have been trying to get a script to place a date in an adjacent cell when a checkbox is checked. This is a minor part of the whole script I am trying to get working. I am trying to write a script to build a new sheet from another sheets values, including naming the sheet.
I can get the script to work when I type the sheet name into the if statement, but when I try and use an argument by calling the sheet name and calling string, I can not get them to return a true value.
When I log the sheet name and the string they match. If I copy and paste ether value from the log into the sheet name it will then return true. It will also return true when I type the name of the sheet.
I have tried to change the type using: toString() but this has not worked.
I have tried to use the length and typeof to find the solution, from this page:
How to debug identical strings that do not equal in google app script?
But they where the same type and length. I have tried to get the every function on this page to work but have been unsuccessful in getting it to run.
I have used it like this:
[td].every((char,i) => char === nac[i] || console.info(`Unequal character at ${i}`))
and get this error:
10:55:03 AM Error
TypeError: Cannot read property 'every' of undefined
onEdit # Time Stamp test day.gs:33
Code:
function onEdit(e) {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var ac = ss.getActiveSheet();
var as = ss.getActiveSheet().getSheetName();
var d = new Date();
var month = new Array(12);
month[0] = "Jan";
month[1] = "Feb";
month[2] = "Mar";
month[3] = "Apl";
month[4] = "May";
month[5] = "Jun";
month[6] = "Jul";
month[7] = "Aug";
month[8] = "Sep";
month[9] = "Oct";
month[10] = "Nov";
month[11] = "Dec";
var year = d.getFullYear();
var date = d.getDate();
var today = month[d.getMonth()] + " " + date +", " + year
var td = "Test " + today
var nac = ac.getSheetName()
Logger.log(td)
Logger.log(nac)
Logger.log(nac == td)
if(nac == td) {
var cell = ac.getActiveCell()
var col = cell.getColumn()
if(col == 9 && cell.getValue() == true){
Logger.log(123456)
var date = new Date()
var dateCell = cell.offset(0,1)
dateCell.setValue(date)
}//close if
} // Close if
} // Close function
Log
11:26:46 PM Notice Execution started
11:26:47 PM Info Test Dec 27, 2020
11:26:47 PM Info Test Dec 27, 2020
11:26:47 PM Info false
11:26:47 PM Notice Execution completed