using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

public static class IListExtensions
{
	public static bool NullOrEmpty<T>(this IList<T> list)
	{
		return list == null || list.Any() == false;
	}

	public static bool NotNullOrEmpty<T>(this IList<T> list)
	{
		return NullOrEmpty<T>(list) == false;
	}

	public static void AddDistinct<T>(this IList<T> list, T item)
	{
		if (item == null || list.Contains(item))
		{ return; }

		list.Add(item);
	}

	public static void AddRangeDistinct<T>(this IList<T> list, IEnumerable<T> collection)
	{
		if (collection == null)
		{ return; }

		foreach(T item in collection)
		{ AddDistinct(list, item); }
	}
}