- sequenceArray
- traverseArray
- traverseArrayWithIndex
- traverseReadonlyArrayWithIndex
- traverseReadonlyNonEmptyArrayWithIndex
- ApT
- ap
- apFirst
- apFirstW
- apSecond
- apSecondW
- apW
- compose
- do
- first
getMonoid(deprecated)getSemigroup(deprecated)- left
- let
- local
- promap
reader(deprecated)- right
- second
export declare const Applicative: Applicative2<URI>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const Apply: Apply2<URI>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const Category: Category2<URI>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const Chain: chainable.Chain2<URI>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
ChainRec for Reader
export declare const ChainRec: ChainRec2<URI>
- Added in 0.1.0
- MIT – Copyright (c) 2022-present Jacob Alford
export declare const Choice: Choice2<URI>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const Functor: Functor2<URI>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const Monad: Monad2<URI>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const Pointed: Pointed2<URI>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const Profunctor: Profunctor2<URI>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const Strong: Strong2<URI>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Composes computations in sequence, using the return value of one computation to determine the next computation and keeping only the result of the first.
export declare const tap: {
<R1, A, R2, _>(self: Reader<R1, A>, f: (a: A) => Reader<R2, _>): Reader<R1 & R2, A>
<A, R2, _>(f: (a: A) => Reader<R2, _>): <R1>(self: Reader<R1, A>) => Reader<R2 & R1, A>
}
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Reads the current context
export declare const ask: <R>() => Reader<R, R>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Projects a value from the global context in a Reader
export declare const asks: <R, A>(f: (r: R) => A) => Reader<R, A>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Effectfully accesses the environment.
export declare const asksReader: <R, A>(f: (r: R) => Reader<R, A>) => Reader<R, A>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Less strict version of asksReader
.
The W
suffix (short for Widening) means that the environment types will be merged.
export declare const asksReaderW: <R1, R2, A>(f: (r1: R1) => Reader<R2, A>) => Reader<R1 & R2, A>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const id: Category2<URI>['id']
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const of: <R = unknown, A = never>(a: A) => Reader<R, A>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const Do: Reader<unknown, {}>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const apS: <N extends string, A, E, B>(
name: Exclude<N, keyof A>,
fb: Reader<E, B>,
) => (fa: Reader<E, A>) => Reader<E, { readonly [K in N | keyof A]: K extends keyof A ? A[K] : B }>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Less strict version of apS
.
The W
suffix (short for Widening) means that the environment types will be merged.
export declare const apSW: <A, N extends string, R2, B>(
name: Exclude<N, keyof A>,
fb: Reader<R2, B>,
) => <R1>(fa: Reader<R1, A>) => Reader<
R1 & R2,
{
readonly [K in keyof A | N]: K extends keyof A ? A[K] : B
}
>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const bind: <N extends string, A, E, B>(
name: Exclude<N, keyof A>,
f: (a: A) => Reader<E, B>,
) => (ma: Reader<E, A>) => Reader<E, { readonly [K in N | keyof A]: K extends keyof A ? A[K] : B }>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const bindTo: <N extends string>(
name: N,
) => <E, A>(fa: Reader<E, A>) => Reader<E, { readonly [K in N]: A }>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
The W
suffix (short for Widening) means that the environment types will be merged.
export declare const bindW: <N extends string, A, R2, B>(
name: Exclude<N, keyof A>,
f: (a: A) => Reader<R2, B>,
) => <R1>(fa: Reader<R1, A>) => Reader<
R1 & R2,
{
readonly [K in keyof A | N]: K extends keyof A ? A[K] : B
}
>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const chainRec: ChainRec2<URI>['chainRec']
- Added in 0.1.0
- MIT – Copyright (c) 2022-present Jacob Alford
Alias of flatMap
.
export declare const chain: <A, R, B>(f: (a: A) => Reader<R, B>) => (ma: Reader<R, A>) => Reader<R, B>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Alias of tap
.
export declare const chainFirst: <A, R, B>(f: (a: A) => Reader<R, B>) => (first: Reader<R, A>) => Reader<R, A>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Alias of tap
.
export declare const chainFirstW: <R2, A, B>(
f: (a: A) => Reader<R2, B>,
) => <R1>(ma: Reader<R1, A>) => Reader<R1 & R2, A>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Alias of flatMap
.
export declare const chainW: <R2, A, B>(f: (a: A) => Reader<R2, B>) => <R1>(ma: Reader<R1, A>) => Reader<R1 & R2, B>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const flap: <A>(a: A) => <E, B>(fab: Reader<E, (a: A) => B>) => Reader<E, B>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
map
can be used to turn functions (a: A) => B
into functions (fa: F<A>) => F<B>
whose argument and return types use the type constructor F
to represent some computational context.
export declare const map: <A, B>(f: (a: A) => B) => <R>(fa: Reader<R, A>) => Reader<R, B>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export interface Reader<R, A> {
(r: R): A
}
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const flatMap: {
<A, R2, B>(f: (a: A) => Reader<R2, B>): <R1>(ma: Reader<R1, A>) => Reader<R1 & R2, B>
<R1, A, R2, B>(ma: Reader<R1, A>, f: (a: A) => Reader<R2, B>): Reader<R1 & R2, B>
}
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const flatten: <R, A>(mma: Reader<R, Reader<R, A>>) => Reader<R, A>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Less strict version of flatten
.
The W
suffix (short for Widening) means that the environment types will be merged.
export declare const flattenW: <R1, R2, A>(mma: Reader<R1, Reader<R2, A>>) => Reader<R1 & R2, A>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Equivalent to ReadonlyArray#sequence(Applicative)
.
export declare const sequenceArray: <R, A>(arr: ReadonlyArray<Reader<R, A>>) => Reader<R, ReadonlyArray<A>>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Equivalent to ReadonlyArray#traverse(Applicative)
.
export declare const traverseArray: <R, A, B>(
f: (a: A) => Reader<R, B>,
) => (as: readonly A[]) => Reader<R, readonly B[]>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Equivalent to ReadonlyArray#traverseWithIndex(Applicative)
.
export declare const traverseArrayWithIndex: <R, A, B>(
f: (index: number, a: A) => Reader<R, B>,
) => (as: ReadonlyArray<A>) => Reader<R, ReadonlyArray<B>>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Equivalent to ReadonlyArray#traverseWithIndex(Applicative)
.
export declare const traverseReadonlyArrayWithIndex: <A, R, B>(
f: (index: number, a: A) => Reader<R, B>,
) => (as: readonly A[]) => Reader<R, readonly B[]>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Equivalent to ReadonlyNonEmptyArray#traverseWithIndex(Applicative)
.
export declare const traverseReadonlyNonEmptyArrayWithIndex: <A, R, B>(
f: (index: number, a: A) => Reader<R, B>,
) => (as: ReadonlyNonEmptyArray<A>) => Reader<R, ReadonlyNonEmptyArray<B>>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export type URI = typeof URI
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const URI = 'Reader'
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const ApT: Reader<unknown, readonly []>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const ap: <R, A>(fa: Reader<R, A>) => <B>(fab: Reader<R, (a: A) => B>) => Reader<R, B>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Combine two effectful actions, keeping only the result of the first.
export declare const apFirst: <E, B>(second: Reader<E, B>) => <A>(first: Reader<E, A>) => Reader<E, A>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Less strict version of apFirst
.
The W
suffix (short for Widening) means that the environment types will be merged.
export declare const apFirstW: <R2, B>(second: Reader<R2, B>) => <R1, A>(first: Reader<R1, A>) => Reader<R1 & R2, A>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Combine two effectful actions, keeping only the result of the second.
export declare const apSecond: <E, B>(second: Reader<E, B>) => <A>(first: Reader<E, A>) => Reader<E, B>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Less strict version of apSecond
.
The W
suffix (short for Widening) means that the environment types will be merged.
export declare const apSecondW: <R2, B>(second: Reader<R2, B>) => <R1, A>(first: Reader<R1, A>) => Reader<R1 & R2, B>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Less strict version of ap
.
The W
suffix (short for Widening) means that the environment types will be merged.
export declare const apW: <R2, A>(fa: Reader<R2, A>) => <R1, B>(fab: Reader<R1, (a: A) => B>) => Reader<R1 & R2, B>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const compose: <A, B>(ab: Reader<A, B>) => <C>(bc: Reader<B, C>) => Reader<A, C>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const do_: <MA extends ReaderIterable<any, any>, A>(
yieldFunction: (unwrap: <R, A>(ma: Reader<R, A>) => ReaderIterable<R, A>) => Generator<MA, A>,
) => Reader<_.UnionToIntersection<MA extends ReaderIterable<infer R, any> ? R : never>, A>
export declare const first: Strong2<URI>['first']
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
Use getApplicativeMonoid
instead.
export declare const getMonoid: <R, A>(M: Monoid<A>) => Monoid<Reader<R, A>>
- Added in 0.1.0
- Deprecated
- MIT – Copyright (c) 2017-present Giulio Canti
Use getApplySemigroup
instead.
export declare const getSemigroup: <R, A>(S: Semigroup<A>) => Semigroup<Reader<R, A>>
- Added in 0.1.0
- Deprecated
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const left: Choice2<URI>['left']
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const let_: <N extends string, A, B>(
name: Exclude<N, keyof A>,
f: (a: A) => B,
) => <E>(fa: Reader<E, A>) => Reader<E, { readonly [K in N | keyof A]: K extends keyof A ? A[K] : B }>
Changes the value of the local context during the execution of the action ma
(similar to Contravariant
's contramap
).
export declare const local: <R2, R1>(f: (r2: R2) => R1) => <A>(ma: Reader<R1, A>) => Reader<R2, A>
- Added in 0.1.0
import { pipe } from '@fp-tx/core/function'
import * as R from '@fp-tx/core/Reader'
import * as string from '@fp-tx/core/string'
const calculateContentLen: R.Reader<string, number> = pipe(
R.Do,
R.bind('content', () => R.ask<string>()),
R.map(({ content }) => string.size(content)),
)
// Calls calculateContentLen after adding a prefix to the Reader content.
const calculateModifiedContentLen: R.Reader<string, number> = pipe(
calculateContentLen,
R.local(s => 'Prefix ' + s),
)
const s = '12345'
assert.deepStrictEqual(
"Modified 's' length: " +
calculateModifiedContentLen(s) +
'\n' +
"Original 's' length: " +
calculateContentLen(s),
"Modified 's' length: 12\nOriginal 's' length: 5",
)
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const promap: <E, A, D, B>(f: (d: D) => E, g: (a: A) => B) => (fea: Reader<E, A>) => Reader<D, B>
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
This instance is deprecated, use small, specific instances instead. For example if a function needs a Functor
instance, pass R.Functor
instead of R.reader
(where R
is from import R from 'fp-ts/Reader'
)
export declare const reader: Monad2<URI> & Profunctor2<URI> & Category2<URI> & Strong2<URI> & Choice2<URI>
- Added in 0.1.0
- Deprecated
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const right: Choice2<URI>['right']
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti
export declare const second: Strong2<URI>['second']
- Added in 0.1.0
- MIT – Copyright (c) 2017-present Giulio Canti