equal

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 whether the two given keysets have the same elements, using strict equality

namespace HH\Lib\Keyset;

function equal<Tv as arraykey>(
  keyset<Tv> $keyset1,
  keyset<Tv> $keyset2,
): bool;

To guarantee equality of order as well as contents, use ===.

Time complexity: O(n) Space complexity: O(1)

Parameters

• keyset<Tv> $keyset1
• keyset<Tv> $keyset2

Returns

• bool

Examples

$result = Keyset\equal(keyset[1,2,3,4], keyset[1,2,3,4]);
print_r($result);
//result: true

$result = Keyset\equal(keyset[1,2,3,4], keyset[4,2,3,1]);
print_r($result);
//result: true

$result = Keyset\equal(keyset[1,2,3,4],  keyset[1,2,3,4,5]);
print_r($result);
//result: false