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State

Instances​

Combinators​

Constructors​

Instance methods​

Legacy​

Mapping​

Model​

Sequencing​

Traversing​

Type lambdas​

Utilities​

Instances​

Applicative​

Signature​

export declare const Applicative: Applicative2<URI>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Apply​

Signature​

export declare const Apply: Apply2<URI>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Chain​

Signature​

export declare const Chain: chainable.Chain2<URI>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

ChainRec​

ChainRec for State

Signature​

export declare const ChainRec: ChainRec2<URI>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2022-present Jacob Alford

FromState​

Signature​

export declare const FromState: FromState2<URI>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Functor​

Signature​

export declare const Functor: Functor2<URI>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Monad​

Signature​

export declare const Monad: Monad2<URI>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Pointed​

Signature​

export declare const Pointed: Pointed2<URI>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Combinators​

tap​

Composes computations in sequence, using the return value of one computation to determine the next computation and keeping only the result of the first.

Signature​

export declare const tap: {
  <S, A, _>(self: State<S, A>, f: (a: A) => State<S, _>): State<S, A>
  <A, S, _>(f: (a: A) => State<S, _>): (self: State<S, A>) => State<S, A>
}

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Constructors​

get​

Get the current state

Signature​

export declare const get: <S>() => State<S, S>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

gets​

Get a value which depends on the current state

Signature​

export declare const gets: <S, A>(f: (s: S) => A) => State<S, A>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

modify​

Modify the state by applying a function to the current state

Signature​

export declare const modify: <S>(f: (s: S) => S) => State<S, void>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

of​

Signature​

export declare const of: <S, A>(a: A) => State<S, A>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

put​

Set the state

Signature​

export declare const put: <S>(s: S) => State<S, void>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Instance methods​

chainRec​

Signature​

export declare const chainRec: ChainRec2<URI>['chainRec']

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2022-present Jacob Alford

Legacy​

chain​

Alias of flatMap.

Signature​

export declare const chain: <S, A, B>(f: (a: A) => State<S, B>) => (ma: State<S, A>) => State<S, B>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

chainFirst​

Alias of tap.

Signature​

export declare const chainFirst: <S, A, B>(f: (a: A) => State<S, B>) => (ma: State<S, A>) => State<S, A>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Mapping​

flap​

Signature​

export declare const flap: <A>(a: A) => <E, B>(fab: State<E, (a: A) => B>) => State<E, B>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

map​

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.

Signature​

export declare const map: <A, B>(f: (a: A) => B) => <E>(fa: State<E, A>) => State<E, B>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Model​

State​

Signature​

export interface State<S, A> {
  (s: S): [A, S]
}

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Sequencing​

flatMap​

Signature​

export declare const flatMap: {
  <A, S, B>(f: (a: A) => State<S, B>): (ma: State<S, A>) => State<S, B>
  <S, A, B>(ma: State<S, A>, f: (a: A) => State<S, B>): State<S, B>
}

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

flatten​

Signature​

export declare const flatten: <E, A>(mma: State<E, State<E, A>>) => State<E, A>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Traversing​

sequenceArray​

Equivalent to ReadonlyArray#sequence(Applicative).

Signature​

export declare const sequenceArray: <S, A>(arr: ReadonlyArray<State<S, A>>) => State<S, ReadonlyArray<A>>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

traverseArray​

Equivalent to ReadonlyArray#traverse(Applicative).

Signature​

export declare const traverseArray: <A, S, B>(f: (a: A) => State<S, B>) => (as: readonly A[]) => State<S, readonly B[]>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

traverseArrayWithIndex​

Equivalent to ReadonlyArray#traverseWithIndex(Applicative).

Signature​

export declare const traverseArrayWithIndex: <A, S, B>(
  f: (index: number, a: A) => State<S, B>,
) => (as: ReadonlyArray<A>) => State<S, ReadonlyArray<B>>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

traverseReadonlyArrayWithIndex​

Equivalent to ReadonlyArray#traverseWithIndex(Applicative).

Signature​

export declare const traverseReadonlyArrayWithIndex: <A, S, B>(
  f: (index: number, a: A) => State<S, B>,
) => (as: readonly A[]) => State<S, readonly B[]>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

traverseReadonlyNonEmptyArrayWithIndex​

Equivalent to ReadonlyNonEmptyArray#traverseWithIndex(Applicative).

Signature​

export declare const traverseReadonlyNonEmptyArrayWithIndex: <A, S, B>(
  f: (index: number, a: A) => State<S, B>,
) => (as: ReadonlyNonEmptyArray<A>) => State<S, ReadonlyNonEmptyArray<B>>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Type lambdas​

URI​

Signature​

export type URI = typeof URI

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

URI​

Signature​

export declare const URI = 'State'

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

Utilities​

ap​

Signature​

export declare const ap: <E, A>(fa: State<E, A>) => <B>(fab: State<E, (a: A) => B>) => State<E, B>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

apFirst​

Combine two effectful actions, keeping only the result of the first.

Signature​

export declare const apFirst: <E, B>(second: State<E, B>) => <A>(first: State<E, A>) => State<E, A>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

apS​

Signature​

export declare const apS: <N extends string, A, E, B>(
  name: Exclude<N, keyof A>,
  fb: State<E, B>,
) => (fa: State<E, A>) => State<E, { readonly [K in N | keyof A]: K extends keyof A ? A[K] : B }>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

apSecond​

Combine two effectful actions, keeping only the result of the second.

Signature​

export declare const apSecond: <E, B>(second: State<E, B>) => <A>(first: State<E, A>) => State<E, B>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

bind​

Signature​

export declare const bind: <N extends string, A, E, B>(
  name: Exclude<N, keyof A>,
  f: (a: A) => State<E, B>,
) => (ma: State<E, A>) => State<E, { readonly [K in N | keyof A]: K extends keyof A ? A[K] : B }>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

bindTo​

Signature​

export declare const bindTo: <N extends string>(
  name: N,
) => <E, A>(fa: State<E, A>) => State<E, { readonly [K in N]: A }>

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

do​

Signature​

export declare const do_: <MA extends StateIterable<any, any>, A>(
  yieldFunction: (unwrap: <S, A>(ma: State<S, A>) => StateIterable<S, A>) => Generator<MA, A>,
) => State<_.UnionToIntersection<MA extends StateIterable<infer S, any> ? S : never>, A>

evalState​

Use evaluate instead

Signature​

export declare const evalState: <S, A>(ma: State<S, A>, s: S) => A

Details​

  • Added in 0.1.0
  • Deprecated

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

evaluate​

Run a computation in the State monad, discarding the final state

Signature​

export declare const evaluate: <S>(s: S) => <A>(ma: State<S, A>) => A

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

execState​

Use execute instead

Signature​

export declare const execState: <S, A>(ma: State<S, A>, s: S) => S

Details​

  • Added in 0.1.0
  • Deprecated

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

execute​

Run a computation in the State monad discarding the result

Signature​

export declare const execute: <S>(s: S) => <A>(ma: State<S, A>) => S

Details​

  • Added in 0.1.0

License​

  • MIT – Copyright (c) 2017-present Giulio Canti

let​

Signature​

export declare const let_: <N extends string, A, B>(
  name: Exclude<N, keyof A>,
  f: (a: A) => B,
) => <E>(fa: State<E, A>) => State<E, { readonly [K in N | keyof A]: K extends keyof A ? A[K] : B }>

state​

This instance is deprecated, use small, specific instances instead. For example if a function needs a Functor instance, pass S.Functor instead of S.state (where S is from import S from 'fp-ts/State')

Signature​

export declare const state: Monad2<URI>

Details​

  • Added in 0.1.0
  • Deprecated

License​

  • MIT – Copyright (c) 2017-present Giulio Canti