Shapes

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.

Interface Synopsis

namespace HH\Readonly;

abstract final class Shapes {...}

Public Methods

• ::at(shape() $shape, arraykey $index): mixed
  Returns the value of the field $index of a readonly $shape, throws if the field is missing
• ::idx(shape(...) $shape, arraykey $index, mixed $default = NULL): mixed
  Use Readonly\Shapes::idx to retrieve a field value in a shape, when the key may or may not exist
• ::toArray(shape() $shape): darray<arraykey, mixed>
• ::toDict(shape() $shape): dict<arraykey, mixed>