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NonEmptyArray overview

Data structure which represents non-empty arrays

Added in v2.0.0

Table of contents

Alt

alt

Identifies an associative operation on a type constructor. It is similar to Semigroup, except that it applies to types of kind * -> *.

Signature

export declare const alt: <A>(that: Lazy<NonEmptyArray<A>>) => (fa: NonEmptyArray<A>) => NonEmptyArray<A>

Added in v2.6.2

Applicative

of

Signature

export declare const of: <A>(a: A) => NonEmptyArray<A>

Added in v2.0.0

Apply

ap

Apply a function to an argument under a type constructor.

Signature

export declare const ap: <A>(fa: NonEmptyArray<A>) => <B>(fab: NonEmptyArray<(a: A) => B>) => NonEmptyArray<B>

Added in v2.0.0

apFirst

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

Signature

export declare const apFirst: <B>(fb: NonEmptyArray<B>) => <A>(fa: NonEmptyArray<A>) => NonEmptyArray<A>

Added in v2.0.0

apSecond

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

Signature

export declare const apSecond: <B>(fb: NonEmptyArray<B>) => <A>(fa: NonEmptyArray<A>) => NonEmptyArray<B>

Added in v2.0.0

Extend

duplicate

Signature

export declare const duplicate: <A>(ma: NonEmptyArray<A>) => NonEmptyArray<NonEmptyArray<A>>

Added in v2.0.0

extend

Signature

export declare const extend: <A, B>(f: (fa: NonEmptyArray<A>) => B) => (ma: NonEmptyArray<A>) => NonEmptyArray<B>

Added in v2.0.0

Foldable

foldMap

Signature

export declare const foldMap: <S>(S: Semigroup<S>) => <A>(f: (a: A) => S) => (fa: NonEmptyArray<A>) => S

Added in v2.0.0

reduce

Signature

export declare const reduce: <A, B>(b: B, f: (b: B, a: A) => B) => (fa: NonEmptyArray<A>) => B

Added in v2.0.0

reduceRight

Signature

export declare const reduceRight: <A, B>(b: B, f: (a: A, b: B) => B) => (fa: NonEmptyArray<A>) => B

Added in v2.0.0

FoldableWithIndex

foldMapWithIndex

Signature

export declare const foldMapWithIndex: <S>(
  S: Semigroup<S>
) => <A>(f: (i: number, a: A) => S) => (fa: NonEmptyArray<A>) => S

Added in v2.0.0

reduceRightWithIndex

Signature

export declare const reduceRightWithIndex: <A, B>(b: B, f: (i: number, a: A, b: B) => B) => (fa: NonEmptyArray<A>) => B

Added in v2.0.0

reduceWithIndex

Signature

export declare const reduceWithIndex: <A, B>(b: B, f: (i: number, b: B, a: A) => B) => (fa: NonEmptyArray<A>) => 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) => (fa: NonEmptyArray<A>) => NonEmptyArray<B>

Added in v2.0.0

FunctorWithIndex

mapWithIndex

Signature

export declare const mapWithIndex: <A, B>(f: (i: number, a: A) => B) => (fa: NonEmptyArray<A>) => NonEmptyArray<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: <A, B>(f: (a: A) => NonEmptyArray<B>) => (ma: NonEmptyArray<A>) => NonEmptyArray<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.

Signature

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

Added in v2.0.0

flatten

Signature

export declare const flatten: <A>(mma: NonEmptyArray<NonEmptyArray<A>>) => NonEmptyArray<A>

Added in v2.0.0

combinators

copy

Signature

export declare function copy<A>(nea: NonEmptyArray<A>): NonEmptyArray<A>

Added in v2.0.0

filter

Signature

export declare function filter<A, B extends A>(
  refinement: Refinement<A, B>
): (nea: NonEmptyArray<A>) => Option<NonEmptyArray<A>>
export declare function filter<A>(predicate: Predicate<A>): (nea: NonEmptyArray<A>) => Option<NonEmptyArray<A>>

Added in v2.0.0

group

Group equal, consecutive elements of an array into non empty arrays.

Signature

export declare function group<A>(
  E: Eq<A>
): {
  (as: NonEmptyArray<A>): NonEmptyArray<NonEmptyArray<A>>
  (as: Array<A>): Array<NonEmptyArray<A>>
}

Example

import { cons, group } from 'fp-ts/lib/NonEmptyArray'
import { ordNumber } from 'fp-ts/lib/Ord'

assert.deepStrictEqual(group(ordNumber)([1, 2, 1, 1]), [cons(1, []), cons(2, []), cons(1, [1])])

Added in v2.0.0

groupSort

Sort and then group the elements of an array into non empty arrays.

Signature

export declare const groupSort: <A>(O: Ord<A>) => (as: A[]) => NonEmptyArray<A>[]

Example

import { cons, groupSort } from 'fp-ts/lib/NonEmptyArray'
import { ordNumber } from 'fp-ts/lib/Ord'

assert.deepStrictEqual(groupSort(ordNumber)([1, 2, 1, 1]), [cons(1, [1, 1]), cons(2, [])])

Added in v2.0.0

reverse

Signature

export declare const reverse: <A>(nea: NonEmptyArray<A>) => NonEmptyArray<A>

Added in v2.0.0

sort

Signature

export declare const sort: <A>(O: Ord<A>) => (nea: NonEmptyArray<A>) => NonEmptyArray<A>

Added in v2.0.0

zip

Signature

export declare const zip: {
  <B>(bs: NonEmptyArray<B>): <A>(as: NonEmptyArray<A>) => NonEmptyArray<[A, B]>
  <A, B>(as: NonEmptyArray<A>, bs: NonEmptyArray<B>): NonEmptyArray<[A, B]>
}

Added in v2.5.1

zipWith

Signature

export declare const zipWith: <A, B, C>(
  fa: NonEmptyArray<A>,
  fb: NonEmptyArray<B>,
  f: (a: A, b: B) => C
) => NonEmptyArray<C>

Added in v2.5.1

constructors

concat

Signature

export declare function concat<A>(fx: Array<A>, fy: NonEmptyArray<A>): NonEmptyArray<A>
export declare function concat<A>(fx: NonEmptyArray<A>, fy: Array<A>): NonEmptyArray<A>

Added in v2.2.0

cons

Append an element to the front of an array, creating a new non empty array

Signature

export declare const cons: <A>(head: A, tail: A[]) => NonEmptyArray<A>

Example

import { cons } from 'fp-ts/lib/NonEmptyArray'

assert.deepStrictEqual(cons(1, [2, 3, 4]), [1, 2, 3, 4])

Added in v2.0.0

fromArray

Builds a NonEmptyArray from an Array returning none if as is an empty array

Signature

export declare const fromArray: <A>(as: A[]) => Option<NonEmptyArray<A>>

Added in v2.0.0

groupBy

Splits an array into sub-non-empty-arrays stored in an object, based on the result of calling a string-returning function on each element, and grouping the results according to values returned

Signature

export declare const groupBy: <A>(f: (a: A) => string) => (as: A[]) => Record<string, NonEmptyArray<A>>

Example

import { cons, groupBy } from 'fp-ts/lib/NonEmptyArray'

assert.deepStrictEqual(groupBy((s: string) => String(s.length))(['foo', 'bar', 'foobar']), {
  '3': cons('foo', ['bar']),
  '6': cons('foobar', []),
})

Added in v2.0.0

snoc

Append an element to the end of an array, creating a new non empty array

Signature

export declare const snoc: <A>(init: A[], end: A) => NonEmptyArray<A>

Example

import { snoc } from 'fp-ts/lib/NonEmptyArray'

assert.deepStrictEqual(snoc([1, 2, 3], 4), [1, 2, 3, 4])

Added in v2.0.0

instances

URI

Signature

export declare const URI: 'NonEmptyArray'

Added in v2.0.0

URI (type alias)

Signature

export type URI = typeof URI

Added in v2.0.0

altNonEmptyArray

Signature

export declare const altNonEmptyArray: Alt1<'NonEmptyArray'>

Added in v2.7.0

applicativeNonEmptyArray

Signature

export declare const applicativeNonEmptyArray: Applicative1<'NonEmptyArray'>

Added in v2.7.0

comonadNonEmptyArray

Signature

export declare const comonadNonEmptyArray: Comonad1<'NonEmptyArray'>

Added in v2.7.0

foldableNonEmptyArray

Signature

export declare const foldableNonEmptyArray: Foldable1<'NonEmptyArray'>

Added in v2.7.0

foldableWithIndexNonEmptyArray

Signature

export declare const foldableWithIndexNonEmptyArray: FoldableWithIndex1<'NonEmptyArray', number>

Added in v2.7.0

functorNonEmptyArray

Signature

export declare const functorNonEmptyArray: Functor1<'NonEmptyArray'>

Added in v2.7.0

functorWithIndexNonEmptyArray

Signature

export declare const functorWithIndexNonEmptyArray: FunctorWithIndex1<'NonEmptyArray', number>

Added in v2.7.0

getEq

Signature

export declare const getEq: <A>(E: Eq<A>) => Eq<NonEmptyArray<A>>

Example

import { getEq, cons } from 'fp-ts/lib/NonEmptyArray'
import { eqNumber } from 'fp-ts/lib/Eq'

const E = getEq(eqNumber)
assert.strictEqual(E.equals(cons(1, [2]), [1, 2]), true)
assert.strictEqual(E.equals(cons(1, [2]), [1, 3]), false)

Added in v2.0.0

getSemigroup

Builds a Semigroup instance for NonEmptyArray

Signature

export declare const getSemigroup: <A = never>() => Semigroup<NonEmptyArray<A>>

Added in v2.0.0

getShow

Signature

export declare const getShow: <A>(S: Show<A>) => Show<NonEmptyArray<A>>

Added in v2.0.0

monadNonEmptyArray

Signature

export declare const monadNonEmptyArray: Monad1<'NonEmptyArray'>

Added in v2.7.0

nonEmptyArray

Signature

export declare const nonEmptyArray: Monad1<'NonEmptyArray'> &
  Comonad1<'NonEmptyArray'> &
  TraversableWithIndex1<'NonEmptyArray', number> &
  FunctorWithIndex1<'NonEmptyArray', number> &
  FoldableWithIndex1<'NonEmptyArray', number> &
  Alt1<'NonEmptyArray'>

Added in v2.0.0

traversableNonEmptyArray

Signature

export declare const traversableNonEmptyArray: Traversable1<'NonEmptyArray'>

Added in v2.7.0

traversableWithIndexNonEmptyArray

Signature

export declare const traversableWithIndexNonEmptyArray: TraversableWithIndex1<'NonEmptyArray', number>

Added in v2.7.0

model

NonEmptyArray (interface)

Signature

export interface NonEmptyArray<A> extends Array<A> {
  0: A
}

Added in v2.0.0

utils

extract

Signature

export declare const extract: <A>(wa: NonEmptyArray<A>) => A

Added in v2.7.0

filterWithIndex

Signature

export declare const filterWithIndex: <A>(
  predicate: (i: number, a: A) => boolean
) => (nea: NonEmptyArray<A>) => Option<NonEmptyArray<A>>

Added in v2.0.0

fold

Signature

export declare const fold: <A>(S: Semigroup<A>) => (fa: NonEmptyArray<A>) => A

Added in v2.5.0

Signature

export declare const head: <A>(nea: NonEmptyArray<A>) => A

Added in v2.0.0

init

Get all but the last element of a non empty array, creating a new array.

Signature

export declare const init: <A>(nea: NonEmptyArray<A>) => A[]

Example

import { init } from 'fp-ts/lib/NonEmptyArray'

assert.deepStrictEqual(init([1, 2, 3]), [1, 2])
assert.deepStrictEqual(init([1]), [])

Added in v2.2.0

insertAt

Signature

export declare const insertAt: <A>(i: number, a: A) => (nea: NonEmptyArray<A>) => Option<NonEmptyArray<A>>

Added in v2.0.0

last

Signature

export declare const last: <A>(nea: NonEmptyArray<A>) => A

Added in v2.0.0

max

Signature

export declare const max: <A>(ord: Ord<A>) => (nea: NonEmptyArray<A>) => A

Added in v2.0.0

min

Signature

export declare const min: <A>(ord: Ord<A>) => (nea: NonEmptyArray<A>) => A

Added in v2.0.0

modifyAt

Signature

export declare const modifyAt: <A>(i: number, f: (a: A) => A) => (nea: NonEmptyArray<A>) => Option<NonEmptyArray<A>>

Added in v2.0.0

sequence

Signature

export declare const sequence: Sequence1<'NonEmptyArray'>

Added in v2.6.3

tail

Signature

export declare const tail: <A>(nea: NonEmptyArray<A>) => A[]

Added in v2.0.0

traverse

Signature

export declare const traverse: PipeableTraverse1<'NonEmptyArray'>

Added in v2.6.3

traverseWithIndex

Signature

export declare const traverseWithIndex: PipeableTraverseWithIndex1<'NonEmptyArray', number>

Added in v2.6.3

unzip

Signature

export declare const unzip: <A, B>(as: NonEmptyArray<[A, B]>) => [NonEmptyArray<A>, NonEmptyArray<B>]

Added in v2.5.1

updateAt

Signature

export declare const updateAt: <A>(i: number, a: A) => (nea: NonEmptyArray<A>) => Option<NonEmptyArray<A>>

Added in v2.0.0