HH\Lib\C\first
Requires the Hack Standard Library to be installed.
Facebook Engineer?
This function is available as C\first() in Facebook's www repository.
Returns the first element of the given Traversable, or null if the Traversable is empty
namespace HH\Lib\C;
function first<T>(
Traversable<T> $traversable,
): ?T;
- For non-empty Traversables, see
C\firstx. - For possibly null Traversables, see
C\nfirst. - For single-element Traversables, see
C\onlyx. - For Awaitables that yield Traversables, see
C\first_async.
Time complexity: O(1) Space complexity: O(1)
Parameters
Returns
?T