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interface Functor<F> {
  readonly URI: F
  readonly map: <A, B>(fa: HKT<F, A>, f: (a: A) => B) => HKT<F, B>

Added in v1.0.0 (type class)

A Functor is a type constructor which supports a mapping operation map.

map can be used to turn functions a -> b into functions f a -> f b whose argument and return types use the type constructor f to represent some computational context.

Instances must satisfy the following laws:

  1. Identity: F.map(fa, a => a) = fa
  2. Composition: F.map(fa, a => bc(ab(a))) = F.map(F.map(fa, ab), bc)


flap<F>(functor: Functor<F>): <A, B>(a: A, ff: HKT<F, (a: A) => B>) => HKT<F, B>

Added in v1.0.0 (function)

Apply a value in a computational context to a value in no context. Generalizes flip


getFunctorComposition<F, G>(F: Functor<F>, G: Functor<G>): FunctorComposition<F, G>

Added in v1.0.0 (function)


lift<F>(F: Functor<F>): <A, B>(f: (a: A) => B) => (fa: HKT<F, A>) => HKT<F, B>

Added in v1.0.0 (function)

Lift a function of one argument to a function which accepts and returns values wrapped with the type constructor F


voidLeft<F>(F: Functor<F>): <A, B>(fa: HKT<F, A>, b: B) => HKT<F, B>

Added in v1.0.0 (function)

A version of voidRight with its arguments flipped ($>)


voidRight<F>(F: Functor<F>): <A, B>(a: A, fb: HKT<F, B>) => HKT<F, A>

Added in v1.0.0 (function)

Ignore the return value of a computation, using the specified return value instead (<$)