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sort

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 keyset sorted by the values of the given Traversable

namespace HH\Lib\Keyset;

function sort<Tv as arraykey>(
  Traversable<Tv> $traversable,
  ?(function(Tv, Tv): num) $comparator = NULL,
): keyset<Tv>;

If the optional comparator function isn't provided, the values will be sorted in ascending order.

Time complexity: O((n log n) * c), where c is the complexity of the comparator function (which is O(1) if not explicitly provided) Space complexity: O(n)

Parameters​

Returns​

  • keyset<Tv>

Examples​

$result = Keyset\sort(keyset[1,200, 5]);
print_r($result);
//result: keyset[1,5,200]

$result = Keyset\sort(keyset[100,2000,3,4]);
print_r($result);
//result: keyset[3,4,100,2000]