MapAccess

:::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 setting and removing Map keys (and associated values)

This interface provides no new methods as all current access for Maps are defined in its parent interfaces. But you could theoretically use this interface for parameter and return type annotations.

Guides

• Introduction
• Interfaces

Interface Synopsis

interface MapAccess implements ConstMapAccess<Tk, Tv>, SetAccess<Tk>, IndexAccess<Tk, Tv> {...}

Public Methods (ConstSetAccess)

• ->contains(arraykey $m): bool
  Checks whether a value is in the current Set

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

Public Methods (SetAccess)

• ->remove(Tm $m): this
  Removes the provided value from the current Set

Public Methods (IndexAccess)

• ->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