hphp/hack/manual/apis/Classes/HH/ImmSet/fromKeysOf.md
:::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. :::
Creates an ImmSet from the keys of the specified container
public static function fromKeysOf<Tk as arraykey>(
?KeyedContainer<Tk, mixed> $container,
): ImmSet<Tk>;
The keys of the container will be the values of the ImmSet.
?KeyedContainer<Tk,mixed> $container - The container with the keys used to create the
ImmSet.ImmSet<Tk> - An ImmSet built from the keys of the specified container.See Set::fromKeysOf for usage examples.