/// <summary>
/// See if this enumeration has all items in passed enumeration. Returns true if passed enum is empty.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="a"></param>
/// <param name="b"></param>
/// <returns></returns>
public async static Task <bool> ContainsAllItems <T>(this IAsyncEnumerable <T> a, IAsyncEnumerable <T> b)
{
if (!await b.Any())
{
return(true);
}
return(!await b.Except(a).Any());
}
public static Task <bool> Contains <TSource>(this IAsyncEnumerable <TSource> source, TSource value, IEqualityComparer <TSource> comparer, CancellationToken cancellationToken)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (comparer == null)
{
throw new ArgumentNullException(nameof(comparer));
}
return(source.Any(x => comparer.Equals(x, value), cancellationToken));
}
private static async Task <bool> IsEmpty_ <TSource>(IAsyncEnumerable <TSource> source, CancellationToken cancellationToken)
{
return(!await source.Any(cancellationToken)
.ConfigureAwait(false));
}
private static Task <bool> AnyAsyncShim <TSource>(IAsyncEnumerable <TSource> source)
{
return(source.Any());
}
