/** * ```ts * type Option<A> = None | Some<A> * ``` * * `Option<A>` is a container for an optional value of type `A`. If the value of type `A` is present, the `Option<A>` is * an instance of `Some<A>`, containing the present value of type `A`. If the value is absent, the `Option<A>` is an * instance of `None`. * * An option could be looked at as a collection or foldable structure with either one or zero elements. * Another way to look at `Option` is: it represents the effect of a possibly failing computation. * * * @example * import * as O from 'fp-ts/Option' * import { pipe } from 'fp-ts/function' * * const double = (n: number): number => n * 2 * * export const imperative = (as: ReadonlyArray<number>): string => { * const head = (as: ReadonlyArray<number>): number => { * if (as.length === 0) { * throw new Error() * } * return as[0] * } * const inverse = (n: number): number => { * if (n === 0) { * throw new Error() * } * return 1 / n * } * try { * return `Result is ${inverse(double(head(as)))}` * } catch (e) { * return 'no result' * } * } * * export const functional = (as: ReadonlyArray<number>): string => { * const head = <A>(as: ReadonlyArray<A>): O.Option<A> => * as.length === 0 ? O.none : O.some(as[0]) * const inverse = (n: number): O.Option<number> => * n === 0 ? O.none : O.some(1 / n) * return pipe( * as, * head, * O.map(double), * O.chain(inverse), * O.match( * () => 'no result', // onNone handler * (head) => `Result is ${head}` // onSome handler * ) * ) * } * * assert.deepStrictEqual(imperative([1, 2, 3]), functional([1, 2, 3])) * assert.deepStrictEqual(imperative([]), functional([])) * assert.deepStrictEqual(imperative([0]), functional([0])) * * @since 2.0.0 */ import { Alt1 } from './Alt' import { Alternative1 } from './Alternative' import { Applicative1 } from './Applicative' import { Apply1 } from './Apply' import { Chain1 } from './Chain' import { Compactable1 } from './Compactable' import { Either } from './Either' import { Eq } from './Eq' import { Extend1 } from './Extend' import { Filterable1 } from './Filterable' import { Foldable1 } from './Foldable' import { FromEither1 } from './FromEither' import { Lazy } from './function' import { Functor1 } from './Functor' import { Monad1 } from './Monad' import { MonadThrow1 } from './MonadThrow' import { Monoid } from './Monoid' import { Ord } from './Ord' import { Pointed1 } from './Pointed' import { Predicate } from './Predicate' import { ReadonlyNonEmptyArray } from './ReadonlyNonEmptyArray' import { Refinement } from './Refinement' import { Semigroup } from './Semigroup' import { Separated } from './Separated' import { Show } from './Show' import { PipeableTraverse1, Traversable1 } from './Traversable' import { PipeableWilt1, PipeableWither1, Witherable1 } from './Witherable' import { Zero1 } from './Zero' /** * @category model * @since 2.0.0 */ export interface None { readonly _tag: 'None' } /** * @category model * @since 2.0.0 */ export interface Some<A> { readonly _tag: 'Some' readonly value: A } /** * @category model * @since 2.0.0 */ export declare type Option<A> = None | Some<A> /** * `None` doesn't have a constructor, instead you can use it directly as a value. Represents a missing value. * * @category constructors * @since 2.0.0 */ export declare const none: Option<never> /** * Constructs a `Some`. Represents an optional value that exists. * * @category constructors * @since 2.0.0 */ export declare const some: <A>(a: A) => Option<A> /** * Returns a *smart constructor* based on the given predicate. * * @example * import { none, some, fromPredicate } from 'fp-ts/Option' * * const getOption = fromPredicate((n: number) => n >= 0) * * assert.deepStrictEqual(getOption(-1), none) * assert.deepStrictEqual(getOption(1), some(1)) * * @category lifting * @since 2.0.0 */ export declare function fromPredicate<A, B extends A>(refinement: Refinement<A, B>): (a: A) => Option<B> export declare function fromPredicate<A>(predicate: Predicate<A>): <B extends A>(b: B) => Option<B> export declare function fromPredicate<A>(predicate: Predicate<A>): (a: A) => Option<A> /** * Returns the `Left` value of an `Either` if possible. * * @example * import { getLeft, none, some } from 'fp-ts/Option' * import { right, left } from 'fp-ts/Either' * * assert.deepStrictEqual(getLeft(right(1)), none) * assert.deepStrictEqual(getLeft(left('a')), some('a')) * * @category constructors * @since 2.0.0 */ export declare const getLeft: <E, A>(ma: Either<E, A>) => Option<E> /** * Returns the `Right` value of an `Either` if possible. * * @example * import { getRight, none, some } from 'fp-ts/Option' * import { right, left } from 'fp-ts/Either' * * assert.deepStrictEqual(getRight(right(1)), some(1)) * assert.deepStrictEqual(getRight(left('a')), none) * * @category constructors * @since 2.0.0 */ export declare const getRight: <E, A>(ma: Either<E, A>) => Option<A> /** * @category type lambdas * @since 2.0.0 */ export declare const URI = 'Option' /** * @category type lambdas * @since 2.0.0 */ export declare type URI = typeof URI declare module './HKT' { interface URItoKind<A> { readonly [URI]: Option<A> } } /** * @category instances * @since 2.0.0 */ export declare const getShow: <A>(S: Show<A>) => Show<Option<A>> /** * @example * import { none, some, getEq } from 'fp-ts/Option' * import * as N from 'fp-ts/number' * * const E = getEq(N.Eq) * assert.strictEqual(E.equals(none, none), true) * assert.strictEqual(E.equals(none, some(1)), false) * assert.strictEqual(E.equals(some(1), none), false) * assert.strictEqual(E.equals(some(1), some(2)), false) * assert.strictEqual(E.equals(some(1), some(1)), true) * * @category instances * @since 2.0.0 */ export declare const getEq: <A>(E: Eq<A>) => Eq<Option<A>> /** * The `Ord` instance allows `Option` values to be compared with * `compare`, whenever there is an `Ord` instance for * the type the `Option` contains. * * `None` is considered to be less than any `Some` value. * * * @example * import { none, some, getOrd } from 'fp-ts/Option' * import * as N from 'fp-ts/number' * * const O = getOrd(N.Ord) * assert.strictEqual(O.compare(none, none), 0) * assert.strictEqual(O.compare(none, some(1)), -1) * assert.strictEqual(O.compare(some(1), none), 1) * assert.strictEqual(O.compare(some(1), some(2)), -1) * assert.strictEqual(O.compare(some(1), some(1)), 0) * * @category instances * @since 2.0.0 */ export declare const getOrd: <A>(O: Ord<A>) => Ord<Option<A>> /** * Monoid returning the left-most non-`None` value. If both operands are `Some`s then the inner values are * concatenated using the provided `Semigroup` * * | x | y | concat(x, y) | * | ------- | ------- | ------------------ | * | none | none | none | * | some(a) | none | some(a) | * | none | some(b) | some(b) | * | some(a) | some(b) | some(concat(a, b)) | * * @example * import { getMonoid, some, none } from 'fp-ts/Option' * import { SemigroupSum } from 'fp-ts/number' * * const M = getMonoid(SemigroupSum) * assert.deepStrictEqual(M.concat(none, none), none) * assert.deepStrictEqual(M.concat(some(1), none), some(1)) * assert.deepStrictEqual(M.concat(none, some(1)), some(1)) * assert.deepStrictEqual(M.concat(some(1), some(2)), some(3)) * * @category instances * @since 2.0.0 */ export declare const getMonoid: <A>(S: Semigroup<A>) => Monoid<Option<A>> /** * @category mapping * @since 2.0.0 */ export declare const map: <A, B>(f: (a: A) => B) => (fa: Option<A>) => Option<B> /** * @category instances * @since 2.7.0 */ export declare const Functor: Functor1<URI> /** * @category constructors * @since 2.7.0 */ export declare const of: <A>(a: A) => Option<A> /** * @category instances * @since 2.10.0 */ export declare const Pointed: Pointed1<URI> /** * @since 2.0.0 */ export declare const ap: <A>(fa: Option<A>) => <B>(fab: Option<(a: A) => B>) => Option<B> /** * @category instances * @since 2.10.0 */ export declare const Apply: Apply1<URI> /** * @category instances * @since 2.7.0 */ export declare const Applicative: Applicative1<URI> /** * Composes computations in sequence, using the return value of one computation to determine the next computation. * * @category sequencing * @since 2.0.0 */ export declare const chain: <A, B>(f: (a: A) => Option<B>) => (ma: Option<A>) => Option<B> /** * @category instances * @since 2.10.0 */ export declare const Chain: Chain1<URI> /** * @category instances * @since 2.7.0 */ export declare const Monad: Monad1<URI> /** * @category folding * @since 2.0.0 */ export declare const reduce: <A, B>(b: B, f: (b: B, a: A) => B) => (fa: Option<A>) => B /** * @category folding * @since 2.0.0 */ export declare const foldMap: <M>(M: Monoid<M>) => <A>(f: (a: A) => M) => (fa: Option<A>) => M /** * @category folding * @since 2.0.0 */ export declare const reduceRight: <A, B>(b: B, f: (a: A, b: B) => B) => (fa: Option<A>) => B /** * @category instances * @since 2.7.0 */ export declare const Foldable: Foldable1<URI> /** * Less strict version of [`alt`](#alt). * * The `W` suffix (short for **W**idening) means that the return types will be merged. * * @category error handling * @since 2.9.0 */ export declare const altW: <B>(that: Lazy<Option<B>>) => <A>(fa: Option<A>) => Option<A | B> /** * Identifies an associative operation on a type constructor. It is similar to `Semigroup`, except that it applies to * types of kind `* -> *`. * * In case of `Option` returns the left-most non-`None` value. * * | x | y | pipe(x, alt(() => y) | * | ------- | ------- | -------------------- | * | none | none | none | * | some(a) | none | some(a) | * | none | some(b) | some(b) | * | some(a) | some(b) | some(a) | * * @example * import * as O from 'fp-ts/Option' * import { pipe } from 'fp-ts/function' * * assert.deepStrictEqual( * pipe( * O.none, * O.alt(() => O.none) * ), * O.none * ) * assert.deepStrictEqual( * pipe( * O.some('a'), * O.alt<string>(() => O.none) * ), * O.some('a') * ) * assert.deepStrictEqual( * pipe( * O.none, * O.alt(() => O.some('b')) * ), * O.some('b') * ) * assert.deepStrictEqual( * pipe( * O.some('a'), * O.alt(() => O.some('b')) * ), * O.some('a') * ) * * @category error handling * @since 2.0.0 */ export declare const alt: <A>(that: Lazy<Option<A>>) => (fa: Option<A>) => Option<A> /** * @category instances * @since 2.7.0 */ export declare const Alt: Alt1<URI> /** * @since 2.7.0 */ export declare const zero: <A>() => Option<A> /** * @category instances * @since 2.11.0 */ export declare const Zero: Zero1<URI> /** * @category do notation * @since 2.11.0 */ export declare const guard: (b: boolean) => Option<void> /** * @category instances * @since 2.7.0 */ export declare const Alternative: Alternative1<URI> /** * @since 2.0.0 */ export declare const extend: <A, B>(f: (wa: Option<A>) => B) => (wa: Option<A>) => Option<B> /** * @category instances * @since 2.7.0 */ export declare const Extend: Extend1<URI> /** * @category filtering * @since 2.0.0 */ export declare const compact: <A>(fa: Option<Option<A>>) => Option<A> /** * @category filtering * @since 2.0.0 */ export declare const separate: <A, B>(ma: Option<Either<A, B>>) => Separated<Option<A>, Option<B>> /** * @category instances * @since 2.7.0 */ export declare const Compactable: Compactable1<URI> /** * @category filtering * @since 2.0.0 */ export declare const filter: { <A, B extends A>(refinement: Refinement<A, B>): (fa: Option<A>) => Option<B> <A>(predicate: Predicate<A>): <B extends A>(fb: Option<B>) => Option<B> <A>(predicate: Predicate<A>): (fa: Option<A>) => Option<A> } /** * @category filtering * @since 2.0.0 */ export declare const filterMap: <A, B>(f: (a: A) => Option<B>) => (fa: Option<A>) => Option<B> /** * @category filtering * @since 2.0.0 */ export declare const partition: { <A, B extends A>(refinement: Refinement<A, B>): (fa: Option<A>) => Separated<Option<A>, Option<B>> <A>(predicate: Predicate<A>): <B extends A>(fb: Option<B>) => Separated<Option<B>, Option<B>> <A>(predicate: Predicate<A>): (fa: Option<A>) => Separated<Option<A>, Option<A>> } /** * @category filtering * @since 2.0.0 */ export declare const partitionMap: <A, B, C>( f: (a: A) => Either<B, C> ) => (fa: Option<A>) => Separated<Option<B>, Option<C>> /** * @category instances * @since 2.7.0 */ export declare const Filterable: Filterable1<URI> /** * @category traversing * @since 2.6.3 */ export declare const traverse: PipeableTraverse1<URI> /** * @category traversing * @since 2.6.3 */ export declare const sequence: Traversable1<URI>['sequence'] /** * @category instances * @since 2.7.0 */ export declare const Traversable: Traversable1<URI> /** * @category filtering * @since 2.6.5 */ export declare const wither: PipeableWither1<URI> /** * @category filtering * @since 2.6.5 */ export declare const wilt: PipeableWilt1<URI> /** * @category instances * @since 2.7.0 */ export declare const Witherable: Witherable1<URI> /** * @since 2.7.0 */ export declare const throwError: MonadThrow1<URI>['throwError'] /** * @category instances * @since 2.7.0 */ export declare const MonadThrow: MonadThrow1<URI> /** * Transforms an `Either` to an `Option` discarding the error. * * Alias of [getRight](#getright) * * @category conversions * @since 2.0.0 */ export declare const fromEither: <A>(fa: Either<unknown, A>) => Option<A> /** * @category instances * @since 2.11.0 */ export declare const FromEither: FromEither1<URI> /** * Returns `true` if the option is an instance of `Some`, `false` otherwise. * * @example * import { some, none, isSome } from 'fp-ts/Option' * * assert.strictEqual(isSome(some(1)), true) * assert.strictEqual(isSome(none), false) * * @category refinements * @since 2.0.0 */ export declare const isSome: <A>(fa: Option<A>) => fa is Some<A> /** * Returns `true` if the option is `None`, `false` otherwise. * * @example * import { some, none, isNone } from 'fp-ts/Option' * * assert.strictEqual(isNone(some(1)), false) * assert.strictEqual(isNone(none), true) * * @category refinements * @since 2.0.0 */ export declare const isNone: (fa: Option<unknown>) => fa is None /** * Less strict version of [`match`](#match). * * The `W` suffix (short for **W**idening) means that the handler return types will be merged. * * @category pattern matching * @since 2.10.0 */ export declare const matchW: <B, A, C>(onNone: Lazy<B>, onSome: (a: A) => C) => (ma: Option<A>) => B | C /** * Alias of [`matchW`](#matchw). * * @category pattern matching * @since 2.10.0 */ export declare const foldW: <B, A, C>(onNone: Lazy<B>, onSome: (a: A) => C) => (ma: Option<A>) => B | C /** * Takes a (lazy) default value, a function, and an `Option` value, if the `Option` value is `None` the default value is * returned, otherwise the function is applied to the value inside the `Some` and the result is returned. * * @example * import { some, none, match } from 'fp-ts/Option' * import { pipe } from 'fp-ts/function' * * assert.strictEqual( * pipe( * some(1), * match(() => 'a none', a => `a some containing ${a}`) * ), * 'a some containing 1' * ) * * assert.strictEqual( * pipe( * none, * match(() => 'a none', a => `a some containing ${a}`) * ), * 'a none' * ) * * @category pattern matching * @since 2.10.0 */ export declare const match: <A, B>(onNone: Lazy<B>, onSome: (a: A) => B) => (ma: Option<A>) => B /** * Alias of [`match`](#match). * * @category pattern matching * @since 2.0.0 */ export declare const fold: <A, B>(onNone: Lazy<B>, onSome: (a: A) => B) => (ma: Option<A>) => B /** * Less strict version of [`getOrElse`](#getorelse). * * The `W` suffix (short for **W**idening) means that the handler return type will be merged. * * @category error handling * @since 2.6.0 */ export declare const getOrElseW: <B>(onNone: Lazy<B>) => <A>(ma: Option<A>) => B | A /** * Extracts the value out of the structure, if it exists. Otherwise returns the given default value * * @example * import { some, none, getOrElse } from 'fp-ts/Option' * import { pipe } from 'fp-ts/function' * * assert.strictEqual( * pipe( * some(1), * getOrElse(() => 0) * ), * 1 * ) * assert.strictEqual( * pipe( * none, * getOrElse(() => 0) * ), * 0 * ) * * @category error handling * @since 2.0.0 */ export declare const getOrElse: <A>(onNone: Lazy<A>) => (ma: Option<A>) => A /** * @category mapping * @since 2.10.0 */ export declare const flap: <A>(a: A) => <B>(fab: Option<(a: A) => B>) => Option<B> /** * Combine two effectful actions, keeping only the result of the first. * * @since 2.0.0 */ export declare const apFirst: <B>(second: Option<B>) => <A>(first: Option<A>) => Option<A> /** * Combine two effectful actions, keeping only the result of the second. * * @since 2.0.0 */ export declare const apSecond: <B>(second: Option<B>) => <A>(first: Option<A>) => Option<B> /** * @category sequencing * @since 2.0.0 */ export declare const flatten: <A>(mma: Option<Option<A>>) => Option<A> /** * Composes computations in sequence, using the return value of one computation to determine the next computation and * keeping only the result of the first. * * @category sequencing * @since 2.0.0 */ export declare const chainFirst: <A, B>(f: (a: A) => Option<B>) => (first: Option<A>) => Option<A> /** * @since 2.0.0 */ export declare const duplicate: <A>(ma: Option<A>) => Option<Option<A>> /** * @category lifting * @since 2.11.0 */ export declare const fromEitherK: <E, A extends ReadonlyArray<unknown>, B>( f: (...a: A) => Either<E, B> ) => (...a: A) => Option<B> /** * @category sequencing * @since 2.11.0 */ export declare const chainEitherK: <E, A, B>(f: (a: A) => Either<E, B>) => (ma: Option<A>) => Option<B> /** * @category sequencing * @since 2.12.0 */ export declare const chainFirstEitherK: <E, A, B>(f: (a: A) => Either<E, B>) => (ma: Option<A>) => Option<A> /** * Constructs a new `Option` from a nullable type. If the value is `null` or `undefined`, returns `None`, otherwise * returns the value wrapped in a `Some`. * * @example * import { none, some, fromNullable } from 'fp-ts/Option' * * assert.deepStrictEqual(fromNullable(undefined), none) * assert.deepStrictEqual(fromNullable(null), none) * assert.deepStrictEqual(fromNullable(1), some(1)) * * @category conversions * @since 2.0.0 */ export declare const fromNullable: <A>(a: A) => Option<NonNullable<A>> /** * Transforms an exception into an `Option`. If `f` throws, returns `None`, otherwise returns the output wrapped in a * `Some`. * * See also [`tryCatchK`](#trycatchk). * * @example * import { none, some, tryCatch } from 'fp-ts/Option' * * assert.deepStrictEqual( * tryCatch(() => { * throw new Error() * }), * none * ) * assert.deepStrictEqual(tryCatch(() => 1), some(1)) * * @category interop * @since 2.0.0 */ export declare const tryCatch: <A>(f: Lazy<A>) => Option<A> /** * Converts a function that may throw to one returning a `Option`. * * @category interop * @since 2.10.0 */ export declare const tryCatchK: <A extends readonly unknown[], B>(f: (...a: A) => B) => (...a: A) => Option<B> /** * Returns a *smart constructor* from a function that returns a nullable value. * * @example * import { fromNullableK, none, some } from 'fp-ts/Option' * * const f = (s: string): number | undefined => { * const n = parseFloat(s) * return isNaN(n) ? undefined : n * } * * const g = fromNullableK(f) * * assert.deepStrictEqual(g('1'), some(1)) * assert.deepStrictEqual(g('a'), none) * * @category lifting * @since 2.9.0 */ export declare const fromNullableK: <A extends ReadonlyArray<unknown>, B>( f: (...a: A) => B | null | undefined ) => (...a: A) => Option<NonNullable<B>> /** * This is `chain` + `fromNullable`, useful when working with optional values. * * @example * import { some, none, fromNullable, chainNullableK } from 'fp-ts/Option' * import { pipe } from 'fp-ts/function' * * interface Employee { * readonly company?: { * readonly address?: { * readonly street?: { * readonly name?: string * } * } * } * } * * const employee1: Employee = { company: { address: { street: { name: 'high street' } } } } * * assert.deepStrictEqual( * pipe( * fromNullable(employee1.company), * chainNullableK(company => company.address), * chainNullableK(address => address.street), * chainNullableK(street => street.name) * ), * some('high street') * ) * * const employee2: Employee = { company: { address: { street: {} } } } * * assert.deepStrictEqual( * pipe( * fromNullable(employee2.company), * chainNullableK(company => company.address), * chainNullableK(address => address.street), * chainNullableK(street => street.name) * ), * none * ) * * @category sequencing * @since 2.9.0 */ export declare const chainNullableK: <A, B>( f: (a: A) => B | null | undefined ) => (ma: Option<A>) => Option<NonNullable<B>> /** * Extracts the value out of the structure, if it exists. Otherwise returns `null`. * * @example * import { some, none, toNullable } from 'fp-ts/Option' * import { pipe } from 'fp-ts/function' * * assert.strictEqual( * pipe( * some(1), * toNullable * ), * 1 * ) * assert.strictEqual( * pipe( * none, * toNullable * ), * null * ) * * @category conversions * @since 2.0.0 */ export declare const toNullable: <A>(ma: Option<A>) => A | null /** * Extracts the value out of the structure, if it exists. Otherwise returns `undefined`. * * @example * import { some, none, toUndefined } from 'fp-ts/Option' * import { pipe } from 'fp-ts/function' * * assert.strictEqual( * pipe( * some(1), * toUndefined * ), * 1 * ) * assert.strictEqual( * pipe( * none, * toUndefined * ), * undefined * ) * * @category conversions * @since 2.0.0 */ export declare const toUndefined: <A>(ma: Option<A>) => A | undefined /** * Returns `true` if `ma` contains `a` * * @example * import { some, none, elem } from 'fp-ts/Option' * import { pipe } from 'fp-ts/function' * import * as N from 'fp-ts/number' * * assert.strictEqual(pipe(some(1), elem(N.Eq)(1)), true) * assert.strictEqual(pipe(some(1), elem(N.Eq)(2)), false) * assert.strictEqual(pipe(none, elem(N.Eq)(1)), false) * * @since 2.0.0 */ export declare function elem<A>(E: Eq<A>): { (a: A): (ma: Option<A>) => boolean (a: A, ma: Option<A>): boolean } /** * Returns `true` if the predicate is satisfied by the wrapped value * * @example * import { some, none, exists } from 'fp-ts/Option' * import { pipe } from 'fp-ts/function' * * assert.strictEqual( * pipe( * some(1), * exists(n => n > 0) * ), * true * ) * assert.strictEqual( * pipe( * some(1), * exists(n => n > 1) * ), * false * ) * assert.strictEqual( * pipe( * none, * exists(n => n > 0) * ), * false * ) * * @since 2.0.0 */ export declare const exists: <A>(predicate: Predicate<A>) => (ma: Option<A>) => boolean /** * @category do notation * @since 2.9.0 */ export declare const Do: Option<{}> /** * @category do notation * @since 2.8.0 */ export declare const bindTo: <N extends string>(name: N) => <A>(fa: Option<A>) => Option<{ readonly [K in N]: A }> declare const let_: <N extends string, A, B>( name: Exclude<N, keyof A>, f: (a: A) => B ) => (fa: Option<A>) => Option<{ readonly [K in N | keyof A]: K extends keyof A ? A[K] : B }> export { /** * @category do notation * @since 2.13.0 */ let_ as let } /** * @category do notation * @since 2.8.0 */ export declare const bind: <N extends string, A, B>( name: Exclude<N, keyof A>, f: (a: A) => Option<B> ) => (ma: Option<A>) => Option<{ readonly [K in N | keyof A]: K extends keyof A ? A[K] : B }> /** * @category do notation * @since 2.8.0 */ export declare const apS: <N extends string, A, B>( name: Exclude<N, keyof A>, fb: Option<B> ) => (fa: Option<A>) => Option<{ readonly [K in N | keyof A]: K extends keyof A ? A[K] : B }> /** * @since 2.11.0 */ export declare const ApT: Option<readonly []> /** * Equivalent to `ReadonlyNonEmptyArray#traverseWithIndex(Applicative)`. * * @category traversing * @since 2.11.0 */ export declare const traverseReadonlyNonEmptyArrayWithIndex: <A, B>( f: (index: number, a: A) => Option<B> ) => (as: ReadonlyNonEmptyArray<A>) => Option<ReadonlyNonEmptyArray<B>> /** * Equivalent to `ReadonlyArray#traverseWithIndex(Applicative)`. * * @category traversing * @since 2.11.0 */ export declare const traverseReadonlyArrayWithIndex: <A, B>( f: (index: number, a: A) => Option<B> ) => (as: readonly A[]) => Option<readonly B[]> /** * Equivalent to `ReadonlyArray#traverseWithIndex(Applicative)`. * * @category traversing * @since 2.9.0 */ export declare const traverseArrayWithIndex: <A, B>( f: (index: number, a: A) => Option<B> ) => (as: ReadonlyArray<A>) => Option<ReadonlyArray<B>> /** * Equivalent to `ReadonlyArray#traverse(Applicative)`. * * @category traversing * @since 2.9.0 */ export declare const traverseArray: <A, B>(f: (a: A) => Option<B>) => (as: readonly A[]) => Option<readonly B[]> /** * Equivalent to `ReadonlyArray#sequence(Applicative)`. * * @category traversing * @since 2.9.0 */ export declare const sequenceArray: <A>(arr: ReadonlyArray<Option<A>>) => Option<ReadonlyArray<A>> /** * Use `Refinement` module instead. * * @category zone of death * @since 2.0.0 * @deprecated */ export declare function getRefinement<A, B extends A>(getOption: (a: A) => Option<B>): Refinement<A, B> /** * Use [`chainNullableK`](#chainnullablek) instead. * * @category zone of death * @since 2.0.0 * @deprecated */ export declare const mapNullable: <A, B>(f: (a: A) => B | null | undefined) => (ma: Option<A>) => Option<NonNullable<B>> /** * This instance is deprecated, use small, specific instances instead. * For example if a function needs a `Functor` instance, pass `O.Functor` instead of `O.option` * (where `O` is from `import O from 'fp-ts/Option'`) * * @category zone of death * @since 2.0.0 * @deprecated */ export declare const option: Monad1<URI> & Foldable1<URI> & Alternative1<URI> & Extend1<URI> & Witherable1<URI> & MonadThrow1<URI> /** * Use [`getApplySemigroup`](./Apply.ts.html#getapplysemigroup) instead. * * @category zone of death * @since 2.0.0 * @deprecated */ export declare const getApplySemigroup: <A>(S: Semigroup<A>) => Semigroup<Option<A>> /** * Use [`getApplicativeMonoid`](./Applicative.ts.html#getapplicativemonoid) instead. * * @category zone of death * @since 2.0.0 * @deprecated */ export declare const getApplyMonoid: <A>(M: Monoid<A>) => Monoid<Option<A>> /** * Use * * ```ts * import { first } from 'fp-ts/Semigroup' * import { getMonoid } from 'fp-ts/Option' * * getMonoid(first()) * ``` * * instead. * * Monoid returning the left-most non-`None` value * * | x | y | concat(x, y) | * | ------- | ------- | ------------ | * | none | none | none | * | some(a) | none | some(a) | * | none | some(b) | some(b) | * | some(a) | some(b) | some(a) | * * @example * import { getFirstMonoid, some, none } from 'fp-ts/Option' * * const M = getFirstMonoid<number>() * assert.deepStrictEqual(M.concat(none, none), none) * assert.deepStrictEqual(M.concat(some(1), none), some(1)) * assert.deepStrictEqual(M.concat(none, some(2)), some(2)) * assert.deepStrictEqual(M.concat(some(1), some(2)), some(1)) * * @category zone of death * @since 2.0.0 * @deprecated */ export declare const getFirstMonoid: <A = never>() => Monoid<Option<A>> /** * Use * * ```ts * import { last } from 'fp-ts/Semigroup' * import { getMonoid } from 'fp-ts/Option' * * getMonoid(last()) * ``` * * instead. * * Monoid returning the right-most non-`None` value * * | x | y | concat(x, y) | * | ------- | ------- | ------------ | * | none | none | none | * | some(a) | none | some(a) | * | none | some(b) | some(b) | * | some(a) | some(b) | some(b) | * * @example * import { getLastMonoid, some, none } from 'fp-ts/Option' * * const M = getLastMonoid<number>() * assert.deepStrictEqual(M.concat(none, none), none) * assert.deepStrictEqual(M.concat(some(1), none), some(1)) * assert.deepStrictEqual(M.concat(none, some(2)), some(2)) * assert.deepStrictEqual(M.concat(some(1), some(2)), some(2)) * * @category zone of death * @since 2.0.0 * @deprecated */ export declare const getLastMonoid: <A = never>() => Monoid<Option<A>>