Append Value to Delimited List

declare @mylist nvarchar(100)
set @mylist = 'A,B, C, D , 1, 2,345, EFG, H'
select dbo.fn_ListAppend(@mylist, 8, ',')

CREATE FUNCTION [dbo].[fn_ListAppend] (@ValueList nvarchar(4000), @Item nvarchar(4000), @Delim varchar(50)= ',' )
RETURNS nvarchar(4000)
AS
/*********************
-- START DOC --
FUNCTION: fn_ListAppend
    Parameter:    [IN] @ValueList nvarchar(4000)
            [IN] @Item nvarchar(2000)
            [IN] @Delim varchar(50)
            [RETURN] @Value nvarchar(4000)
    Type:        nvarchar
    
    Characteristic:    DETERMINISTIC
    Description:    Returns the "@ValueList" with the "@Item" appended to it.
    
    Example:    declare @mylist nvarchar(100)
            set @mylist = 'A,B, C, D , 1, 2,345, EFG, H'
            select dbo.fn_ListAppend(@mylist, 8, ',') -- Returns "A,B, C, D , 1, 2,345, EFG, H,8"
-- END DOC --
*********************/
BEGIN
    -- If the delimiter passed was null, use an empty string.
    set @Delim = IsNull(@Delim, '')

    -- If the list is empty, set it equal to the value that was passed in.
    if (@ValueList IS NULL)
    begin
        set @ValueList = @Item
    end
    -- If the item passed in was not null, append it to the list.
    else if (@Item IS NOT NULL)
    begin
        set @ValueList = @ValueList + @Delim + @Item
    end

    RETURN @ValueList
END