Previous implementation of getting month name.

gistfile1.txt

	private static getMonthName(month: number): string
	{
		if (month == null)
		{
			return 'XXX';
		}		
    
		var date = new Date();
		date.setMonth(month - 1); // The problem code.
		return date.toLocaleString("en-us", { month: "short" });
	}