hphp/hack/manual/apis/Interfaces/ConstSet/concat.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. :::
Returns a ConstVector that is the concatenation of the values of the
current ConstSet and the values of the provided Traversable
public function concat<Tu super Tv>(
Traversable<Tu> $traversable,
): ConstVector<Tu>;
The values of the provided Traversable is concatenated to the end of the
current ConstSet to produce the returned ConstVector.
Traversable<Tu>$traversable - The Traversable to concatenate to the current
ConstSet.ConstVector<Tu> - The concatenated ConstVector.