IsReadonly

:::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. :::

Checks if this is a readonly parameter

public function isReadonly(): bool;

Returns

• bool - TRUE if the parameter is readonly, otherwise FALSE