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

This function is available as C\nfirst() in Facebook's www repository.

Returns the first element of the given Traversable, or null if the Traversable is null or empty


namespace HH\Lib\C;

function nfirst<T>(
  ?Traversable<T> $traversable,
): ?T;

For non-null Traversables, see C\first. For non-empty Traversables, see C\firstx. For single-element Traversables, see C\onlyx.


  • ?Traversable<T> $traversable