Identity

The Identity type is a very simple type that has no interesting side effects and is effectively just a container of some value. So why does it exist? The Identity type is often used as the base monad of a monad transformer when no other behaviour is required. For example, Reader.T(Identity) is effectively the same as an ordinary Reader.

Construction

The Identity type consists of a single constructor.

const Identity = require('ramda-fantasy').Identity;
const five = Identity(5);

Alternatively, as Identity implements the Applicative interface, Identity.of could also be used.

Interaction

An Identity instance can be transformed via the methods necessary to implement Functor, Ap and Chain (see their corresponding reference below).

The value contained within an Identity instance can be accessed by calling the get method of the instance.

Reference

Constructors

Identity

:: a -> Identity a

Static functions

Identity.of

:: a -> Identity a

Instance methods

identity.map

:: Identity a ~> (a -> b) -> Identity b

Transforms the value contained within the Identity instance with the provided function.

identity.ap

:: Identity (a -> b) ~> Identity a -> Identity b

Transforms the value within the provided Identity instance using the function contained withing the instance of this Identity.

identity.chain

:: Identity a ~> (a -> Identity b) -> Identity b

Produces a new Identity instance by applying the value of this Identity to the provided function.