Iterator

:::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. :::

For those entities that are Traversable, the Iterator interfaces provides the methods of iteration

If a class implements Iterator, then it provides the infrastructure to be iterated over using a foreach loop.

Guides

• Introduction
• Interfaces

Interface Synopsis

namespace HH;

interface Iterator implements Traversable<Tv> {...}

Public Methods

• ->current(): Tv
  ( excerpt from http://php.net/manual/en/iterator.current.php )
• ->key(): mixed
  ( excerpt from http://php.net/manual/en/iterator.key.php )
• ->next(): void
  ( excerpt from http://php.net/manual/en/iterator.next.php )
• ->rewind(): void
  ( excerpt from http://php.net/manual/en/iterator.rewind.php )
• ->valid(): bool
  ( excerpt from http://php.net/manual/en/iterator.valid.php )