Function mapLeft

packages/typeclass/src/Bicovariant.ts:46–55

(
  F: Bicovariant<F>
)

 * @since 0.24.0
 */
export const mapLeft = <F extends TypeLambda>(
  F: Bicovariant<F>
): {
  <E, G>(f: (e: E) => G): <R, O, A>(self: Kind<F, R, O, E, A>) => Kind<F, R, O, G, A>
  <R, O, E, A, G>(self: Kind<F, R, O, E, A>, f: (e: E) => G): Kind<F, R, O, G, A>
} =>
  dual(
    2,
    <R, O, E, A, G>(self: Kind<F, R, O, E, A>, f: (e: E) => G): Kind<F, R, O, G, A> => F.bimap(self, f, identity)
  )

/**
 * Returns a default `map` implementation.