/** * ```ts * interface TaskEither extends Task> {} * ``` * * `TaskEither` represents an asynchronous computation that either yields a value of type `A` or fails yielding an * error of type `E`. If you want to represent an asynchronous computation that never fails, please see `Task`. * * @since 2.0.0 */ import { Alt2, Alt2C } from './Alt' import { Applicative2, Applicative2C } from './Applicative' import { Apply1 } from './Apply' import { Bifunctor2 } from './Bifunctor' import * as E from './Either' import { Filterable2C } from './Filterable' import { Lazy, Predicate, Refinement } from './function' import { Functor2 } from './Functor' import { IO } from './IO' import { IOEither } from './IOEither' import { Monad2, Monad2C } from './Monad' import { MonadIO2 } from './MonadIO' import { MonadTask2, MonadTask2C } from './MonadTask' import { MonadThrow2, MonadThrow2C } from './MonadThrow' import { Monoid } from './Monoid' import { Option } from './Option' import { Semigroup } from './Semigroup' import * as T from './Task' import Either = E.Either import Task = T.Task /** * @category model * @since 2.0.0 */ export interface TaskEither extends Task> {} /** * @category constructors * @since 2.0.0 */ export declare const left: (e: E) => TaskEither /** * @category constructors * @since 2.0.0 */ export declare const right: (a: A) => TaskEither /** * @category constructors * @since 2.0.0 */ export declare const rightTask: (ma: Task) => TaskEither /** * @category constructors * @since 2.0.0 */ export declare const leftTask: (me: Task) => TaskEither /** * @category constructors * @since 2.0.0 */ export declare const rightIO: (ma: IO) => TaskEither /** * @category constructors * @since 2.0.0 */ export declare const leftIO: (me: IO) => TaskEither /** * @category constructors * @since 2.0.0 */ export declare const fromIOEither: (fa: IOEither) => TaskEither /** * Derivable from `MonadThrow`. * * @category constructors * @since 2.0.0 */ export declare const fromEither: (ma: E.Either) => TaskEither /** * Derivable from `MonadThrow`. * * @category constructors * @since 2.0.0 */ export declare const fromOption: (onNone: Lazy) => (ma: Option) => TaskEither /** * Derivable from `MonadThrow`. * * @category constructors * @since 2.0.0 */ export declare const fromPredicate: { (refinement: Refinement, onFalse: (a: A) => E): (a: A) => TaskEither (predicate: Predicate, onFalse: (a: A) => E): (a: A) => TaskEither } /** * Transforms a `Promise` that may reject to a `Promise` that never rejects and returns an `Either` instead. * * Note: `f` should never `throw` errors, they are not caught. * * @example * import { left, right } from 'fp-ts/Either' * import { tryCatch } from 'fp-ts/TaskEither' * * tryCatch(() => Promise.resolve(1), String)().then(result => { * assert.deepStrictEqual(result, right(1)) * }) * tryCatch(() => Promise.reject('error'), String)().then(result => { * assert.deepStrictEqual(result, left('error')) * }) * * @category constructors * @since 2.0.0 */ export declare function tryCatch(f: Lazy>, onRejected: (reason: unknown) => E): TaskEither /** * @category destructors * @since 2.0.0 */ export declare const fold: ( onLeft: (e: E) => Task, onRight: (a: A) => Task ) => (ma: TaskEither) => Task /** * Less strict version of [`getOrElse`](#getOrElse). * * @category destructors * @since 2.6.0 */ export declare const getOrElseW: (onLeft: (e: E) => T.Task) => (ma: TaskEither) => T.Task /** * @category destructors * @since 2.0.0 */ export declare const getOrElse: (onLeft: (e: E) => Task) => (ma: TaskEither) => Task /** * Returns `ma` if is a `Right` or the value returned by `onLeft` otherwise. * * See also [alt](#alt). * * @example * import * as E from 'fp-ts/Either' * import { pipe } from 'fp-ts/function' * import * as TE from 'fp-ts/TaskEither' * * async function test() { * const errorHandler = TE.orElse((error: string) => TE.right(`recovering from ${error}...`)) * assert.deepStrictEqual(await pipe(TE.right('ok'), errorHandler)(), E.right('ok')) * assert.deepStrictEqual(await pipe(TE.left('ko'), errorHandler)(), E.right('recovering from ko...')) * } * * test() * * @category combinators * @since 2.0.0 */ export declare const orElse: (onLeft: (e: E) => TaskEither) => (ma: TaskEither) => TaskEither /** * @category combinators * @since 2.0.0 */ export declare const swap: (ma: TaskEither) => TaskEither /** * Less strict version of [`filterOrElse`](#filterOrElse). * * @since 2.9.0 */ export declare const filterOrElseW: { (refinement: Refinement, onFalse: (a: A) => E2): ( ma: TaskEither ) => TaskEither (predicate: Predicate, onFalse: (a: A) => E2): (ma: TaskEither) => TaskEither } /** * Derivable from `MonadThrow`. * * @category combinators * @since 2.0.0 */ export declare const filterOrElse: { (refinement: Refinement, onFalse: (a: A) => E): (ma: TaskEither) => TaskEither (predicate: Predicate, onFalse: (a: A) => E): (ma: TaskEither) => TaskEither } /** * Converts a function returning a `Promise` to one returning a `TaskEither`. * * @category combinators * @since 2.5.0 */ export declare function tryCatchK, B>( f: (...a: A) => Promise, onRejected: (reason: unknown) => E ): (...a: A) => TaskEither /** * @category combinators * @since 2.4.0 */ export declare function fromEitherK, B>( f: (...a: A) => Either ): (...a: A) => TaskEither /** * @category combinators * @since 2.4.0 */ export declare function fromIOEitherK, B>( f: (...a: A) => IOEither ): (...a: A) => TaskEither /** * Less strict version of [`chainEitherK`](#chainEitherK). * * @category combinators * @since 2.6.1 */ export declare const chainEitherKW: ( f: (a: A) => Either ) => (ma: TaskEither) => TaskEither /** * @category combinators * @since 2.4.0 */ export declare const chainEitherK: (f: (a: A) => Either) => (ma: TaskEither) => TaskEither /** * Less strict version of [`chainIOEitherK`](#chainIOEitherK). * * @category combinators * @since 2.6.1 */ export declare const chainIOEitherKW: ( f: (a: A) => IOEither ) => (ma: TaskEither) => TaskEither /** * @category combinators * @since 2.4.0 */ export declare const chainIOEitherK: ( f: (a: A) => IOEither ) => (ma: TaskEither) => TaskEither /** * `map` can be used to turn functions `(a: A) => B` into functions `(fa: F) => F` whose argument and return types * use the type constructor `F` to represent some computational context. * * @category Functor * @since 2.0.0 */ export declare const map: (f: (a: A) => B) => (fa: TaskEither) => TaskEither /** * Map a pair of functions over the two type arguments of the bifunctor. * * @category Bifunctor * @since 2.0.0 */ export declare const bimap: (f: (e: E) => G, g: (a: A) => B) => (fa: TaskEither) => TaskEither /** * Map a function over the first type argument of a bifunctor. * * @category Bifunctor * @since 2.0.0 */ export declare const mapLeft: (f: (e: E) => G) => (fa: TaskEither) => TaskEither /** * Less strict version of [`ap`](#ap). * * @category Apply * @since 2.8.0 */ export declare const apW: ( fa: TaskEither ) => (fab: TaskEither B>) => TaskEither /** * Apply a function to an argument under a type constructor. * * @category Apply * @since 2.0.0 */ export declare const ap: (fa: TaskEither) => (fab: TaskEither B>) => TaskEither /** * Combine two effectful actions, keeping only the result of the first. * * Derivable from `Apply`. * * @category combinators * @since 2.0.0 */ export declare const apFirst: (fb: TaskEither) => (fa: TaskEither) => TaskEither /** * Combine two effectful actions, keeping only the result of the second. * * Derivable from `Apply`. * * @category combinators * @since 2.0.0 */ export declare const apSecond: (fb: TaskEither) => (fa: TaskEither) => TaskEither /** * Less strict version of [`chain`](#chain). * * @category Monad * @since 2.6.0 */ export declare const chainW: ( f: (a: A) => TaskEither ) => (ma: TaskEither) => TaskEither /** * Composes computations in sequence, using the return value of one computation to determine the next computation. * * @category Monad * @since 2.0.0 */ export declare const chain: (f: (a: A) => TaskEither) => (ma: TaskEither) => TaskEither /** * Less strict version of [`chainFirst`](#chainFirst). * * Derivable from `Monad`. * * @category combinators * @since 2.8.0 */ export declare const chainFirstW: ( f: (a: A) => TaskEither ) => (ma: TaskEither) => TaskEither /** * Composes computations in sequence, using the return value of one computation to determine the next computation and * keeping only the result of the first. * * Derivable from `Monad`. * * @category combinators * @since 2.0.0 */ export declare const chainFirst: (f: (a: A) => TaskEither) => (ma: TaskEither) => TaskEither /** * Derivable from `Monad`. * * @category combinators * @since 2.0.0 */ export declare const flatten: (mma: TaskEither>) => TaskEither /** * Less strict version of [`alt`](#alt). * * @category Alt * @since 2.9.0 */ export declare const altW: ( that: Lazy> ) => (fa: TaskEither) => TaskEither /** * Identifies an associative operation on a type constructor. It is similar to `Semigroup`, except that it applies to * types of kind `* -> *`. * * In case of `TaskEither` returns `fa` if is a `Right` or the value returned by `that` otherwise. * * See also [orElse](#orElse). * * @example * import * as E from 'fp-ts/Either' * import { pipe } from 'fp-ts/function' * import * as TE from 'fp-ts/TaskEither' * * async function test() { * assert.deepStrictEqual( * await pipe( * TE.right(1), * TE.alt(() => TE.right(2)) * )(), * E.right(1) * ) * assert.deepStrictEqual( * await pipe( * TE.left('a'), * TE.alt(() => TE.right(2)) * )(), * E.right(2) * ) * assert.deepStrictEqual( * await pipe( * TE.left('a'), * TE.alt(() => TE.left('b')) * )(), * E.left('b') * ) * } * * test() * * @category Alt * @since 2.0.0 */ export declare const alt: (that: Lazy>) => (fa: TaskEither) => TaskEither /** * Wrap a value into the type constructor. * * Equivalent to [`right`](#right). * * @category Applicative * @since 2.0.0 */ export declare const of: Applicative2['of'] /** * @category MonadIO * @since 2.7.0 */ export declare const fromIO: MonadIO2['fromIO'] /** * @category MonadTask * @since 2.7.0 */ export declare const fromTask: MonadTask2['fromTask'] /** * @category MonadTask * @since 2.7.0 */ export declare const throwError: MonadThrow2['throwError'] /** * @category instances * @since 2.0.0 */ export declare const URI = 'TaskEither' /** * @category instances * @since 2.0.0 */ export declare type URI = typeof URI declare module './HKT' { interface URItoKind2 { readonly [URI]: TaskEither } } /** * Semigroup returning the left-most non-`Left` value. If both operands are `Right`s then the inner values are * concatenated using the provided `Semigroup` * * @category instances * @since 2.0.0 */ export declare function getSemigroup(S: Semigroup): Semigroup> /** * Semigroup returning the left-most `Left` value. If both operands are `Right`s then the inner values * are concatenated using the provided `Semigroup` * * @category instances * @since 2.0.0 */ export declare function getApplySemigroup(S: Semigroup): Semigroup> /** * @category instances * @since 2.0.0 */ export declare function getApplyMonoid(M: Monoid): Monoid> /** * @category instances * @since 2.7.0 */ export declare function getApplicativeTaskValidation(A: Apply1, SE: Semigroup): Applicative2C /** * @category instances * @since 2.7.0 */ export declare function getAltTaskValidation(SE: Semigroup): Alt2C /** * @category instances * @since 2.0.0 */ export declare function getTaskValidation( SE: Semigroup ): Monad2C & Bifunctor2 & Alt2C & MonadTask2C & MonadThrow2C /** * @category instances * @since 2.1.0 */ export declare function getFilterable(M: Monoid): Filterable2C /** * @category instances * @since 2.7.0 */ export declare const Functor: Functor2 /** * @category instances * @since 2.7.0 */ export declare const ApplicativePar: Applicative2 /** * @category instances * @since 2.7.0 */ export declare const ApplicativeSeq: Applicative2 /** * @category instances * @since 2.7.0 */ export declare const Bifunctor: Bifunctor2 /** * @category instances * @since 2.7.0 */ export declare const Alt: Alt2 /** * @category instances * @since 2.0.0 */ export declare const taskEither: Monad2 & Bifunctor2 & Alt2 & MonadTask2 & MonadThrow2 /** * Like `TaskEither` but `ap` is sequential * * @category instances * @since 2.0.0 */ export declare const taskEitherSeq: typeof taskEither /** * Convert a node style callback function to one returning a `TaskEither` * * **Note**. If the function `f` admits multiple overloadings, `taskify` will pick last one. If you want a different * behaviour, add an explicit type annotation * * ```ts * // readFile admits multiple overloadings * * // const readFile: (a: string) => TaskEither * const readFile = taskify(fs.readFile) * * const readFile2: (filename: string, encoding: string) => TaskEither = taskify( * fs.readFile * ) * ``` * * @example * import { taskify } from 'fp-ts/TaskEither' * import * as fs from 'fs' * * // const stat: (a: string | Buffer) => TaskEither * const stat = taskify(fs.stat) * assert.strictEqual(stat.length, 0) * * @since 2.0.0 */ export declare function taskify(f: (cb: (e: L | null | undefined, r?: R) => void) => void): () => TaskEither export declare function taskify( f: (a: A, cb: (e: L | null | undefined, r?: R) => void) => void ): (a: A) => TaskEither export declare function taskify( f: (a: A, b: B, cb: (e: L | null | undefined, r?: R) => void) => void ): (a: A, b: B) => TaskEither export declare function taskify( f: (a: A, b: B, c: C, cb: (e: L | null | undefined, r?: R) => void) => void ): (a: A, b: B, c: C) => TaskEither export declare function taskify( f: (a: A, b: B, c: C, d: D, cb: (e: L | null | undefined, r?: R) => void) => void ): (a: A, b: B, c: C, d: D) => TaskEither export declare function taskify( f: (a: A, b: B, c: C, d: D, e: E, cb: (e: L | null | undefined, r?: R) => void) => void ): (a: A, b: B, c: C, d: D, e: E) => TaskEither /** * Make sure that a resource is cleaned up in the event of an exception (\*). The release action is called regardless of * whether the body action throws (\*) or returns. * * (\*) i.e. returns a `Left` * * Derivable from `MonadThrow`. * * @since 2.0.0 */ export declare const bracket: ( acquire: TaskEither, use: (a: A) => TaskEither, release: (a: A, e: E.Either) => TaskEither ) => TaskEither /** * @since 2.9.0 */ export declare const Do: TaskEither /** * @since 2.8.0 */ export declare const bindTo: ( name: N ) => (fa: TaskEither) => TaskEither /** * @since 2.8.0 */ export declare const bindW: ( name: Exclude, f: (a: A) => TaskEither ) => (fa: TaskEither) => TaskEither /** * @since 2.8.0 */ export declare const bind: ( name: Exclude, f: (a: A) => TaskEither ) => ( fa: TaskEither ) => TaskEither< E, { [K in keyof A | N]: K extends keyof A ? A[K] : B } > /** * @since 2.8.0 */ export declare const apSW: ( name: Exclude, fb: TaskEither ) => (fa: TaskEither) => TaskEither /** * @since 2.8.0 */ export declare const apS: ( name: Exclude, fb: TaskEither ) => ( fa: TaskEither ) => TaskEither< E, { [K in keyof A | N]: K extends keyof A ? A[K] : B } > /** * @since 2.9.0 */ export declare const traverseArrayWithIndex: ( f: (index: number, a: A) => TaskEither ) => (arr: ReadonlyArray) => TaskEither> /** * this function have the same behavior of `A.traverse(TE.taskEither)` but it's stack safe and perform better * * *this function run all tasks in parallel and does not bail out, for sequential version use `traverseSeqArray`* * * @example * * import * as TE from 'fp-ts/TaskEither' * import * as A from 'fp-ts/Array' * import { right } from 'fp-ts/Either' * import { pipe } from 'fp-ts/function' * * const PostRepo = { * findById : (id: number) => TE.of({id, title: ''}) * } * * const findAllPosts = (ids:number[]) => pipe(ids, TE.traverseArray(PostRepo.findById)) * * async function test() { * const ids = A.range(0, 10) * * assert.deepStrictEqual( * await findAllPosts(ids)(), * right( * pipe( * ids, * A.map((id) => ({ id, title: ''})) * ) * ) * ) * } * * test() * * @since 2.9.0 */ export declare const traverseArray: ( f: (a: A) => TaskEither ) => (arr: ReadonlyArray) => TaskEither> /** * this function have the same behavior of `A.sequence(TE.taskEither)` but it's stack safe and perform better * * *this function run all tasks in parallel and does not bail out, for sequential version use `sequenceSeqArray`* * * @example * * import * as TE from 'fp-ts/TaskEither' * import * as A from 'fp-ts/Array' * import { right } from 'fp-ts/Either' * import { pipe } from 'fp-ts/function' * * const PostRepo = { * findById : (id: number) => TE.of({id, title: ''}) * } * * const findAllPosts = (ids:number[]) => pipe(ids, A.map(PostRepo.findById), TE.sequenceArray) * * async function test() { * const ids = A.range(0, 10) * * assert.deepStrictEqual( * await findAllPosts(ids)(), * right( * pipe( * ids, * A.map((id) => ({ id, title: ''})) * ) * ) * ) * } * * test() * * @since 2.9.0 */ export declare const sequenceArray: (arr: ReadonlyArray>) => TaskEither> /** * @since 2.9.0 */ export declare const traverseSeqArrayWithIndex: ( f: (index: number, a: A) => TaskEither ) => (arr: ReadonlyArray) => TaskEither> /** * this function have the same behavior of `A.traverse(TE.taskEitherSeq)` but it's stack safe and perform better * * *this function run all tasks in sequential order and bails out on left side of either, for parallel version use `traverseArray`* * * @since 2.9.0 */ export declare const traverseSeqArray: ( f: (a: A) => TaskEither ) => (arr: ReadonlyArray) => TaskEither> /** * this function have the same behavior of `A.sequence(TE.taskEitherSeq)` but it's stack safe and perform better * * *this function run all tasks in sequential order and bails out on left side of either, for parallel version use `sequenceArray`* * * @since 2.9.0 */ export declare const sequenceSeqArray: (arr: ReadonlyArray>) => TaskEither>