HH\Lib\Keyset\union

This API is part of the Hack Standard Library, not HHVM itself.

Returns a new keyset containing all of the elements of the given Traversables

namespace HH\Lib\Keyset;

function union<Tv as arraykey>(
    Traversable<Tv> $first,
    Traversable<Tv> ...$rest,
): keyset<Tv>;

For a variable number of Traversables, see Keyset\flatten().

Parameters