IndexAccess

:::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. :::

The interface for mutable, keyed collections to enable setting and removing keys

Guides

• Introduction
• Interfaces

Interface Synopsis

interface IndexAccess implements ConstIndexAccess<Tk, Tv> {...}

Public Methods

• ->removeKey(Tk $k): this
  Removes the specified key (and associated value) from the current collection
• ->set(Tk $k, Tv $v): this
  Stores a value into the current collection with the specified key, overwriting the previous value associated with the key
• ->setAll(?KeyedTraversable<Tk, Tv> $traversable): this
  For every element in the provided Traversable, stores a value into the current collection associated with each key, overwriting the previous value associated with the key

Public Methods (ConstIndexAccess)

• ->at(Tk $k): Tv
  Returns the value at the specified key in the current collection
• ->containsKey(mixed $k): bool
  Determines if the specified key is in the current collection
• ->get(Tk $k): ?Tv
  Returns the value at the specified key in the current collection