State overview
Added in v2.0.0
Table of contents
Apply
ap
Apply a function to an argument under a type constructor.
Signature
export declare const ap: <E, A>(fa: State<E, A>) => <B>(fab: State<E, (a: A) => B>) => State<E, B>
Added in v2.0.0
Functor
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>
Added in v2.0.0
Monad
chain
Composes computations in sequence, using the return value of one computation to determine the next computation.
Signature
export declare const chain: <E, A, B>(f: (a: A) => State<E, B>) => (ma: State<E, A>) => State<E, B>
Added in v2.0.0
Pointed
of
Signature
export declare const of: <E, A>(a: A) => State<E, A>
Added in v2.0.0
combinators
apFirst
Combine two effectful actions, keeping only the result of the first.
Derivable from Apply
.
Signature
export declare const apFirst: <E, B>(second: State<E, B>) => <A>(first: State<E, A>) => State<E, A>
Added in v2.0.0
apSecond
Combine two effectful actions, keeping only the result of the second.
Derivable from Apply
.
Signature
export declare const apSecond: <E, B>(second: State<E, B>) => <A>(first: State<E, A>) => State<E, B>
Added in v2.0.0
chainFirst
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 Chain
.
Signature
export declare const chainFirst: <S, A, B>(f: (a: A) => State<S, B>) => (ma: State<S, A>) => State<S, A>
Added in v2.0.0
flap
Derivable from Functor
.
Signature
export declare const flap: <A>(a: A) => <E, B>(fab: State<E, (a: A) => B>) => State<E, B>
Added in v2.10.0
flatten
Derivable from Chain
.
Signature
export declare const flatten: <E, A>(mma: State<E, State<E, A>>) => State<E, A>
Added in v2.0.0
constructors
get
Get the current state
Signature
export declare const get: <S>() => State<S, S>
Added in v2.0.0
gets
Get a value which depends on the current state
Signature
export declare const gets: <S, A>(f: (s: S) => A) => State<S, A>
Added in v2.0.0
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>
Added in v2.0.0
put
Set the state
Signature
export declare const put: <S>(s: S) => State<S, void>
Added in v2.0.0
instances
Applicative
Signature
export declare const Applicative: Applicative2<'State'>
Added in v2.7.0
Apply
Signature
export declare const Apply: Apply2<'State'>
Added in v2.10.0
Chain
Signature
export declare const Chain: Chain2<'State'>
Added in v2.10.0
FromState
Signature
export declare const FromState: FromState2<'State'>
Added in v2.11.0
Functor
Signature
export declare const Functor: Functor2<'State'>
Added in v2.7.0
Monad
Signature
export declare const Monad: Monad2<'State'>
Added in v2.7.0
Pointed
Signature
export declare const Pointed: Pointed2<'State'>
Added in v2.10.0
URI
Signature
export declare const URI: 'State'
Added in v2.0.0
URI (type alias)
Signature
export type URI = typeof URI
Added in v2.0.0
state
Use small, specific instances instead.
Signature
export declare const state: Monad2<'State'>
Added in v2.0.0
model
State (interface)
Signature
export interface State<S, A> {
(s: S): [A, S]
}
Added in v2.0.0
utils
apS
Signature
export declare const apS: <N, 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 }>
Added in v2.8.0
bind
Signature
export declare const bind: <N, 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 }>
Added in v2.8.0
bindTo
Signature
export declare const bindTo: <N>(name: N) => <E, A>(fa: State<E, A>) => State<E, { readonly [K in N]: A }>
Added in v2.8.0
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
Added in v2.8.0
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
Added in v2.8.0
sequenceArray
Signature
export declare const sequenceArray: <S, A>(arr: readonly State<S, A>[]) => State<S, readonly A[]>
Added in v2.9.0
traverseArray
Signature
export declare const traverseArray: <A, S, B>(f: (a: A) => State<S, B>) => (as: readonly A[]) => State<S, readonly B[]>
Added in v2.9.0
traverseArrayWithIndex
Signature
export declare const traverseArrayWithIndex: <A, S, B>(
f: (index: number, a: A) => State<S, B>
) => (as: readonly A[]) => State<S, readonly B[]>
Added in v2.9.0
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[]>
Added in v2.11.0
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>>
Added in v2.11.0
evalState
Use evaluate
instead
Signature
export declare const evalState: <S, A>(ma: State<S, A>, s: S) => A
Added in v2.0.0
execState
Use execute
instead
Signature
export declare const execState: <S, A>(ma: State<S, A>, s: S) => S
Added in v2.0.0