insertSheet() code example
Example: insertSheet() at the beginning of active sheets google script
var ss = SpreadsheetApp.getActiveSpreadsheet();
ss.insertSheet('My New Sheet', 0);; // .insert(SheetsheetName, atIndex);
var ss = SpreadsheetApp.getActiveSpreadsheet();
ss.insertSheet('My New Sheet', 0);; // .insert(SheetsheetName, atIndex);