filter_async
Note
This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information.
Returns a new vec containing only the values for which the given async
predicate returns true
namespace HH\Lib\Vec;
function filter_async<Tv>(
Container<Tv> $container,
(function(Tv): Awaitable<bool>) $value_predicate,
): Awaitable<vec<Tv>>;
For non-async predicates, see Vec\filter().
Time complexity: O(n * p), where p is the complexity of synchronous portions
of $value_predicate
Space complexity: O(n)
The IO operations for each of the calls to $value_predicate will happen
in parallel.
Parameters
Container<Tv>$container(function(Tv): Awaitable<bool>) $value_predicate