Google Script for Spreadsheets - error: Argument must be a range - google-apps-script

Question

I am new to google scripting and am running into something I can't figure out. I am trying to name a range with the hope of eventually putting it into an array and populating another sheet with the data.
I am running into problems naming the range. I want to eventually be able to iterate through and name many ranges, so I'd like to be able to use variables for the row numbers.
If I try this:
var rngProject = "A8:Y21";
var RngName = "project1";
Then everything works and I have the data in an array. But, as mentioned, I want to use variables for the row numbers, as well as the range name, as shown below.
If I try this:
var rngProject = "A" + strtRow + ":Y" + totRows + strtRow - 1;
var RngName = "project" + toString(i);
On this line:
var rng_to_name = active_spreadsheet.getSheetByName(sheet_name).getRange(address);
I am getting the error: "Argument must be a range." In the debugger the address value shows as NaN, so I think this is not right. But I've also tried using strRange (commented out below) and I get the same error on the same line.
Is there a way I can take this value and cast it to a range type, or is there something else I am doing wrong?
function namePrjRange () {
var i = 1
var strtRow = 8;
var shtName = "USER INPUT by week: TEST";
var totRows = 14;
//var strRange = "A" + toString(strtRow) + ":Y" + toString(totRows + strtRow - 1);
var rngProject = "A" + strtRow + ":Y" + totRows + strtRow - 1;
var RngName = "project" + toString(i);
//Logger.log(strRange);
Logger.log(rngProject);
Logger.log(RngName);
nameRange(shtName, rngProject, RngName);
}
// Given a sheet name (assumed to be in the active spreadsheet, an address using "A1" notation,
// and a name string, assign that name to the range address in the given sheet.
function nameRange(sheet_name, address, rng_name) {
// Create an spreadsheet object.
Logger.log("Entered nameRange function")
var active_spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
// Get a range object by firstly getting a sheet object from the spreadsheet object and then pass the
// "address" argument to the sheet "getRange()" method.
var rng_to_name = active_spreadsheet.getSheetByName(sheet_name).getRange(address);
// Use the spreadsheet object method "setNamedRange()" to assign a range name to a range object.
Logger.log("About to set Named Range");
Logger.log(rng_name);
Logger.log(rng_to_name);
active_spreadsheet.setNamedRange(rng_name, rng_to_name);
}

Answer 1

Use:
var rngProject = "A" + strtRow + ":Y" + (totRows + strtRow - 1);
As you are performing string concatenation here, the parser would be attempting to concatenate everything together (ie not actually adding totRows to strtRow), and ultimately drop it's bundle when it arrives at the minus sign, which isn't a valid string operator. So you just need to put parentheses around the arithmetic part.
https://developer.mozilla.org/en-US/docs/JavaScript/Guide/Expressions_and_Operators#String_operators