Increment

:::info[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. :::

Does the PHP style behaviour when doing an inc/dec operation

namespace HH\Lib\Legacy_FIXME;

function increment(
  mixed $value,
): dynamic;

Specially handles

1. incrementing null
2. inc/dec on empty and numeric strings

Parameters

• mixed $value

Returns

• dynamic