State overview
The State monad is a synonym for the StateT monad transformer, applied to the Identity monad.
Added in v2.0.0
Table of contents
- State (interface)
- URI (type alias)
- URI
- ap
- apFirst
- apSecond
- chain
- chainFirst
- evalState
- execState
- flatten
- get
- gets
- map
- modify
- of
- put
- state
State (interface)
Signature
export interface State<S, A> {
(s: S): [A, S]
}
Added in v2.0.0
URI (type alias)
Signature
export type URI = typeof URI
Added in v2.0.0
URI
Signature
export const URI: "State" = ...
Added in v2.0.0
ap
Signature
<E, A>(fa: State<E, A>) => <B>(fab: State<E, (a: A) => B>) => State<E, B>
Added in v2.0.0
apFirst
Signature
<E, B>(fb: State<E, B>) => <A>(fa: State<E, A>) => State<E, A>
Added in v2.0.0
apSecond
Signature
<E, B>(fb: State<E, B>) => <A>(fa: State<E, A>) => State<E, B>
Added in v2.0.0
chain
Signature
<E, A, B>(f: (a: A) => State<E, B>) => (ma: State<E, A>) => State<E, B>
Added in v2.0.0
chainFirst
Signature
<E, A, B>(f: (a: A) => State<E, B>) => (ma: State<E, A>) => State<E, A>
Added in v2.0.0
evalState
Run a computation in the State monad, discarding the final state
Signature
export const evalState: <S, A>(ma: State<S, A>, s: S) => A = ...
Added in v2.0.0
execState
Run a computation in the State monad discarding the result
Signature
export const execState: <S, A>(ma: State<S, A>, s: S) => S = ...
Added in v2.0.0
flatten
Signature
<E, A>(mma: State<E, State<E, A>>) => State<E, A>
Added in v2.0.0
get
Get the current state
Signature
export const get: <S>() => State<S, S> = ...
Added in v2.0.0
gets
Get a value which depends on the current state
Signature
export const gets: <S, A>(f: (s: S) => A) => State<S, A> = ...
Added in v2.0.0
map
Signature
<A, B>(f: (a: A) => B) => <E>(fa: State<E, A>) => State<E, B>
Added in v2.0.0
modify
Modify the state by applying a function to the current state
Signature
export const modify: <S>(f: (s: S) => S) => State<S, void> = ...
Added in v2.0.0
of
Signature
export const of: <S, A>(a: A) => State<S, A> = ...
Added in v2.0.0
put
Set the state
Signature
export const put: <S>(s: S) => State<S, void> = ...
Added in v2.0.0
state
Signature
export const state: Monad2<URI> = ...
Added in v2.0.0