removeKey

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.

Removes the $index field from the $shape (passed in as an inout argument)

public static function removeKey<T as shape()>(
  inout darray $shape,
  arraykey $index,
): void;

As with all inout arguments, it can only be used with local variables.

Parameters

• inout darray $shape
• arraykey $index

Returns

• void

Examples

This example shows that removeKey directly removes a key from a Shape:

function run(shape('x' => int, 'y' => int) $point): void {
  // Prints the value at key 'y'
  \var_dump($point['y']);

  Shapes::removeKey(inout $point, 'y');

  // Prints NULL because the key 'y' doesn't exist any more
  /* HH_IGNORE_ERROR[4251] typechecker knows the key doesn't exist */
  \var_dump(Shapes::idx($point, 'y'));
}

<<__EntryPoint>>
function basic_usage_main(): void {
  run(shape('x' => 3, 'y' => -1));
}