boolean overview

Added in v2.2.0

---

Table of contents

• instances
  • BooleanAlgebra
  • Eq
  • MonoidAll
  • MonoidAny
  • Ord
  • SemigroupAll
  • SemigroupAny
  • Show
• pattern matching
  • fold
  • foldW
  • match
  • matchW
• refinements
  • isBoolean

---

instances

BooleanAlgebra

Signature

export declare const BooleanAlgebra: BA.BooleanAlgebra<boolean>

Added in v2.10.0

Eq

Signature

export declare const Eq: E.Eq<boolean>

Added in v2.10.0

MonoidAll

boolean monoid under conjunction.

The empty value is true.

Signature

export declare const MonoidAll: Monoid<boolean>

Example

import { MonoidAll } from 'fp-ts/boolean'

assert.deepStrictEqual(MonoidAll.concat(true, true), true)
assert.deepStrictEqual(MonoidAll.concat(true, false), false)

Added in v2.10.0

MonoidAny

boolean monoid under disjunction.

The empty value is false.

Signature

export declare const MonoidAny: Monoid<boolean>

Example

import { MonoidAny } from 'fp-ts/boolean'

assert.deepStrictEqual(MonoidAny.concat(true, true), true)
assert.deepStrictEqual(MonoidAny.concat(true, false), true)
assert.deepStrictEqual(MonoidAny.concat(false, false), false)

Added in v2.10.0

Ord

Signature

export declare const Ord: O.Ord<boolean>

Added in v2.10.0

SemigroupAll

boolean semigroup under conjunction.

Signature

export declare const SemigroupAll: Semigroup<boolean>

Example

import { SemigroupAll } from 'fp-ts/boolean'

assert.deepStrictEqual(SemigroupAll.concat(true, true), true)
assert.deepStrictEqual(SemigroupAll.concat(true, false), false)

Added in v2.10.0

SemigroupAny

boolean semigroup under disjunction.

Signature

export declare const SemigroupAny: Semigroup<boolean>

Example

import { SemigroupAny } from 'fp-ts/boolean'

assert.deepStrictEqual(SemigroupAny.concat(true, true), true)
assert.deepStrictEqual(SemigroupAny.concat(true, false), true)
assert.deepStrictEqual(SemigroupAny.concat(false, false), false)

Added in v2.10.0

Show

Signature

export declare const Show: S.Show<boolean>

Added in v2.10.0

pattern matching

fold

Alias of match.

Signature

export declare const fold: <A>(onFalse: LazyArg<A>, onTrue: LazyArg<A>) => (value: boolean) => A

Added in v2.2.0

foldW

Alias of matchW.

Signature

export declare const foldW: <A, B>(onFalse: LazyArg<A>, onTrue: LazyArg<B>) => (value: boolean) => A | B

Added in v2.10.0

match

Defines the fold over a boolean value. Takes two thunks onTrue, onFalse and a boolean value. If value is false, onFalse() is returned, otherwise onTrue().

Signature

export declare const match: <A>(onFalse: LazyArg<A>, onTrue: LazyArg<A>) => (value: boolean) => A

Example

import { some, map } from 'fp-ts/Option'
import { pipe } from 'fp-ts/function'
import { match } from 'fp-ts/boolean'

assert.deepStrictEqual(
  pipe(
    some(true),
    map(
      match(
        () => 'false',
        () => 'true'
      )
    )
  ),
  some('true')
)

Added in v2.10.0

matchW

Less strict version of match.

The W suffix (short for Widening) means that the handler return types will be merged.

Signature

export declare const matchW: <A, B>(onFalse: LazyArg<A>, onTrue: LazyArg<B>) => (value: boolean) => A | B

Added in v2.10.0

refinements

isBoolean

Signature

export declare const isBoolean: Refinement<unknown, boolean>

Added in v2.11.0