ReaderTaskEither overview

Utility functions to accommodate fp-ts/ReaderTaskEither.

Added in v0.15.0

Table of contents

3 Functions

asksEither

Effectfully accesses the environment outside of the Reader and Task layers.

Signature

export declare const asksEither: <R, E, A>(f: (r: R) => Either<E, A>) => RTE.ReaderTaskEither<R, E, A>

Example

import { asksEither } from 'fp-ts-std/ReaderTaskEither'
import * as E from 'fp-ts/Either'

const lucky = asksEither<number, unknown, boolean>((n) => E.right(n === Date.now()))

assert.deepEqual(lucky(42)(), Promise.resolve(E.right(false)))

Added in v0.16.0

asksTask

Effectfully accesses the environment outside of the Reader and Either layers.

Signature

export declare const asksTask: <R, E, A>(f: (r: R) => Task<A>) => RTE.ReaderTaskEither<R, E, A>

Example

import { asksTask } from 'fp-ts-std/ReaderTaskEither'
import * as E from 'fp-ts/Either'

const lucky = asksTask<number, unknown, boolean>((n) => () => Promise.resolve(n === Date.now()))

assert.deepEqual(lucky(42)(), Promise.resolve(E.right(false)))

Added in v0.16.0

asksTaskEither

Effectfully accesses the environment outside of the Reader layer.

Signature

export declare const asksTaskEither: <R, E, A>(f: (r: R) => TE.TaskEither<E, A>) => RTE.ReaderTaskEither<R, E, A>

Example

import { asksTaskEither } from 'fp-ts-std/ReaderTaskEither'
import * as E from 'fp-ts/Either'

const lucky = asksTaskEither<number, unknown, boolean>((n) => () => Promise.resolve(E.right(n === Date.now())))

assert.deepEqual(lucky(42)(), Promise.resolve(E.right(false)))

Added in v0.16.0

runReaderTaskEither

Runs a ReaderTaskEither and extracts the final TaskEither from it.

Signature

export declare const runReaderTaskEither: <R, E, A>(
  r: R
) => (reader: RTE.ReaderTaskEither<R, E, A>) => TE.TaskEither<E, A>

Example

import { runReaderTaskEither } from 'fp-ts-std/ReaderTaskEither'
import { pipe } from 'fp-ts/function'
import * as RTE from 'fp-ts/ReaderTaskEither'
import * as E from 'fp-ts/Either'

type Env = { dependency: string }
const env: Env = { dependency: 'dependency' }
pipe(E.right(1), RTE.fromEither, runReaderTaskEither(env))().then((extractedValue) =>
  assert.deepStrictEqual(extractedValue, E.right(1))
)

Added in v0.15.0

unsafeUnwrap

Unwrap the promise from within a ReaderTaskEither, rejecting with the inner value of Left if Left.

Signature

export declare const unsafeUnwrap: <R, A>(rte: RTE.ReaderTaskEither<R, unknown, A>) => (r: R) => Promise<A>

Example

import { unsafeUnwrap } from 'fp-ts-std/ReaderTaskEither'
import * as RTE from 'fp-ts/ReaderTaskEither'

unsafeUnwrap(RTE.right(5))({}).then((x) => {
  assert.strictEqual(x, 5)
})

Added in v0.15.0

unsafeUnwrapLeft

Unwrap the promise from within a ReaderTaskEither, throwing the inner value of Right if Right.

Signature

export declare const unsafeUnwrapLeft: <R, E>(rte: RTE.ReaderTaskEither<R, E, unknown>) => (r: R) => Promise<E>

Example

import { unsafeUnwrapLeft } from 'fp-ts-std/ReaderTaskEither'
import * as RTE from 'fp-ts/ReaderTaskEither'

unsafeUnwrapLeft(RTE.left(5))({}).then((x) => {
  assert.strictEqual(x, 5)
})

Added in v0.15.0