function overview
Added in v2.0.0
Table of contents
instances
getBooleanAlgebra
Signature
export declare const getBooleanAlgebra: <B>(B: BooleanAlgebra<B>) => <A = never>() => BooleanAlgebra<(a: A) => B>
Added in v2.10.0
getEndomorphismMonoid
Endomorphism form a monoid where the empty value is the identity function.
Signature
export declare const getEndomorphismMonoid: <A = never>() => Monoid<Endomorphism<A>>
Added in v2.10.0
getMonoid
Unary functions form a monoid as long as you can provide a monoid for the codomain.
Signature
export declare const getMonoid: <M>(M: Monoid<M>) => <A = never>() => Monoid<(a: A) => M>
Example
import { Predicate, getMonoid } from 'fp-ts/function'
import * as B from 'fp-ts/boolean'
const f: Predicate<number> = (n) => n <= 2
const g: Predicate<number> = (n) => n >= 0
const M1 = getMonoid(B.MonoidAll)<number>()
assert.deepStrictEqual(M1.concat(f, g)(1), true)
assert.deepStrictEqual(M1.concat(f, g)(3), false)
const M2 = getMonoid(B.MonoidAny)<number>()
assert.deepStrictEqual(M2.concat(f, g)(1), true)
assert.deepStrictEqual(M2.concat(f, g)(3), true)
Added in v2.10.0
getRing
Signature
export declare const getRing: <A, B>(R: Ring<B>) => Ring<(a: A) => B>
Added in v2.10.0
getSemigroup
Unary functions form a semigroup as long as you can provide a semigroup for the codomain.
Signature
export declare const getSemigroup: <S>(S: Semigroup<S>) => <A = never>() => Semigroup<(a: A) => S>
Example
import { Predicate, getSemigroup } from 'fp-ts/function'
import * as B from 'fp-ts/boolean'
const f: Predicate<number> = (n) => n <= 2
const g: Predicate<number> = (n) => n >= 0
const S1 = getSemigroup(B.SemigroupAll)<number>()
assert.deepStrictEqual(S1.concat(f, g)(1), true)
assert.deepStrictEqual(S1.concat(f, g)(3), false)
const S2 = getSemigroup(B.SemigroupAny)<number>()
assert.deepStrictEqual(S2.concat(f, g)(1), true)
assert.deepStrictEqual(S2.concat(f, g)(3), true)
Added in v2.10.0
getSemiring
Signature
export declare const getSemiring: <A, B>(S: Semiring<B>) => Semiring<(a: A) => B>
Added in v2.10.0
utils
Endomorphism (interface)
Signature
export interface Endomorphism<A> {
(a: A): A
}
Added in v2.0.0
FunctionN (interface)
Signature
export interface FunctionN<A extends ReadonlyArray<unknown>, B> {
(...args: A): B
}
Example
import { FunctionN } from 'fp-ts/function'
export const sum: FunctionN<[number, number], number> = (a, b) => a + b
Added in v2.0.0
Lazy (interface)
A thunk
Signature
export interface Lazy<A> {
(): A
}
Added in v2.0.0
Predicate (interface)
Signature
export interface Predicate<A> {
(a: A): boolean
}
Added in v2.0.0
Refinement (interface)
Signature
export interface Refinement<A, B extends A> {
(a: A): a is B
}
Added in v2.0.0
absurd
Signature
export declare function absurd<A>(_: never): A
Added in v2.0.0
constFalse
A thunk that returns always false.
Signature
export declare const constFalse: Lazy<boolean>
Added in v2.0.0
constNull
A thunk that returns always null.
Signature
export declare const constNull: Lazy<null>
Added in v2.0.0
constTrue
A thunk that returns always true.
Signature
export declare const constTrue: Lazy<boolean>
Added in v2.0.0
constUndefined
A thunk that returns always undefined.
Signature
export declare const constUndefined: Lazy<undefined>
Added in v2.0.0
constVoid
A thunk that returns always void.
Signature
export declare const constVoid: Lazy<void>
Added in v2.0.0
constant
Signature
export declare function constant<A>(a: A): Lazy<A>
Added in v2.0.0
decrement
Signature
export declare function decrement(n: number): number
Added in v2.0.0
flip
Flips the order of the arguments of a function of two arguments.
Signature
export declare function flip<A, B, C>(f: (a: A, b: B) => C): (b: B, a: A) => C
Added in v2.0.0
flow
Performs left-to-right function composition. The first argument may have any arity, the remaining arguments must be unary.
See also pipe.
Signature
export declare function flow<A extends ReadonlyArray<unknown>, B>(ab: (...a: A) => B): (...a: A) => B
export declare function flow<A extends ReadonlyArray<unknown>, B, C>(
ab: (...a: A) => B,
bc: (b: B) => C
): (...a: A) => C
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D>(
ab: (...a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D
): (...a: A) => D
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E>(
ab: (...a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E
): (...a: A) => E
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E, F>(
ab: (...a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F
): (...a: A) => F
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E, F, G>(
ab: (...a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G
): (...a: A) => G
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E, F, G, H>(
ab: (...a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H
): (...a: A) => H
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E, F, G, H, I>(
ab: (...a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I
): (...a: A) => I
export declare function flow<A extends ReadonlyArray<unknown>, B, C, D, E, F, G, H, I, J>(
ab: (...a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J
): (...a: A) => J
Example
import { flow } from 'fp-ts/function'
const len = (s: string): number => s.length
const double = (n: number): number => n * 2
const f = flow(len, double)
assert.strictEqual(f('aaa'), 6)
Added in v2.0.0
hole
Type hole simulation
Signature
export declare const hole: <T>() => T
Added in v2.7.0
identity
Signature
export declare function identity<A>(a: A): A
Added in v2.0.0
increment
Signature
export declare function increment(n: number): number
Added in v2.0.0
not
Signature
export declare function not<A>(predicate: Predicate<A>): Predicate<A>
Added in v2.0.0
pipe
Pipes the value of an expression into a pipeline of functions.
See also flow.
Signature
export declare function pipe<A>(a: A): A
export declare function pipe<A, B>(a: A, ab: (a: A) => B): B
export declare function pipe<A, B, C>(a: A, ab: (a: A) => B, bc: (b: B) => C): C
export declare function pipe<A, B, C, D>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D): D
export declare function pipe<A, B, C, D, E>(a: A, ab: (a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E): E
export declare function pipe<A, B, C, D, E, F>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F
): F
export declare function pipe<A, B, C, D, E, F, G>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G
): G
export declare function pipe<A, B, C, D, E, F, G, H>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H
): H
export declare function pipe<A, B, C, D, E, F, G, H, I>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I
): I
export declare function pipe<A, B, C, D, E, F, G, H, I, J>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J
): J
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J,
jk: (j: J) => K
): K
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J,
jk: (j: J) => K,
kl: (k: K) => L
): L
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J,
jk: (j: J) => K,
kl: (k: K) => L,
lm: (l: L) => M
): M
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J,
jk: (j: J) => K,
kl: (k: K) => L,
lm: (l: L) => M,
mn: (m: M) => N
): N
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J,
jk: (j: J) => K,
kl: (k: K) => L,
lm: (l: L) => M,
mn: (m: M) => N,
no: (n: N) => O
): O
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J,
jk: (j: J) => K,
kl: (k: K) => L,
lm: (l: L) => M,
mn: (m: M) => N,
no: (n: N) => O,
op: (o: O) => P
): P
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J,
jk: (j: J) => K,
kl: (k: K) => L,
lm: (l: L) => M,
mn: (m: M) => N,
no: (n: N) => O,
op: (o: O) => P,
pq: (p: P) => Q
): Q
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J,
jk: (j: J) => K,
kl: (k: K) => L,
lm: (l: L) => M,
mn: (m: M) => N,
no: (n: N) => O,
op: (o: O) => P,
pq: (p: P) => Q,
qr: (q: Q) => R
): R
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J,
jk: (j: J) => K,
kl: (k: K) => L,
lm: (l: L) => M,
mn: (m: M) => N,
no: (n: N) => O,
op: (o: O) => P,
pq: (p: P) => Q,
qr: (q: Q) => R,
rs: (r: R) => S
): S
export declare function pipe<A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T>(
a: A,
ab: (a: A) => B,
bc: (b: B) => C,
cd: (c: C) => D,
de: (d: D) => E,
ef: (e: E) => F,
fg: (f: F) => G,
gh: (g: G) => H,
hi: (h: H) => I,
ij: (i: I) => J,
jk: (j: J) => K,
kl: (k: K) => L,
lm: (l: L) => M,
mn: (m: M) => N,
no: (n: N) => O,
op: (o: O) => P,
pq: (p: P) => Q,
qr: (q: Q) => R,
rs: (r: R) => S,
st: (s: S) => T
): T
Example
import { pipe } from 'fp-ts/function'
const len = (s: string): number => s.length
const double = (n: number): number => n * 2
// without pipe
assert.strictEqual(double(len('aaa')), 6)
// with pipe
assert.strictEqual(pipe('aaa', len, double), 6)
Added in v2.6.3
tuple
Signature
export declare function tuple<T extends ReadonlyArray<any>>(...t: T): T
Added in v2.0.0
tupled
Creates a tupled version of this function: instead of n arguments, it accepts a single tuple argument.
Signature
export declare function tupled<A extends ReadonlyArray<unknown>, B>(f: (...a: A) => B): (a: A) => B
Example
import { tupled } from 'fp-ts/function'
const add = tupled((x: number, y: number): number => x + y)
assert.strictEqual(add([1, 2]), 3)
Added in v2.4.0
unsafeCoerce
Signature
export declare const unsafeCoerce: <A, B>(a: A) => B
Added in v2.0.0
untupled
Inverse function of tupled
Signature
export declare function untupled<A extends ReadonlyArray<unknown>, B>(f: (a: A) => B): (...a: A) => B
Added in v2.4.0