Boolean overview

Various functions to aid in working with booleans. You may also find the Predicate module relevant.

Added in v0.1.0

---

Table of contents

• 1 Typeclass Instances
  • Bounded
  • Enum
• 3 Functions
  • and
  • invert
  • or
  • xor

---

1 Typeclass Instances

Bounded

A Bounded instance for booleans.

Signature

export declare const Bounded: Bounded<boolean>

Bounded :: Bounded boolean

Example

import { Bounded } from 'fp-ts-std/Boolean'

assert.strictEqual(Bounded.top, true)
assert.strictEqual(Bounded.bottom, false)

Added in v0.17.0

Enum

An Enum instance for booleans.

Signature

export declare const Enum: _Enum<boolean>

Enum :: _Enum boolean

Example

import * as O from 'fp-ts/Option'
import { Enum } from 'fp-ts-std/Boolean'

assert.deepStrictEqual(Enum.succ(false), O.some(true))
assert.deepStrictEqual(Enum.succ(true), O.none)

assert.deepStrictEqual(Enum.pred(true), O.some(false))
assert.deepStrictEqual(Enum.pred(false), O.none)

Added in v0.17.0

3 Functions

and

Returns true if both arguments are true, else false. Equivalent to logical conjunction.

Signature

export declare const and: (x: boolean) => Endomorphism<boolean>

and :: boolean -> Endomorphism boolean

Example

import { and } from 'fp-ts-std/Boolean'

assert.strictEqual(and(true)(true), true)
assert.strictEqual(and(true)(false), false)

Added in v0.4.0

invert

Invert a boolean.

Signature

export declare const invert: Endomorphism<boolean>

invert :: Endomorphism boolean

Example

import { invert } from 'fp-ts-std/Boolean'

assert.strictEqual(invert(true), false)
assert.strictEqual(invert(false), true)

Added in v0.4.0

or

Returns true if one or both arguments are true, else false. Equivalent to logical disjunction.

Signature

export declare const or: (x: boolean) => Endomorphism<boolean>

or :: boolean -> Endomorphism boolean

Example

import { or } from 'fp-ts-std/Boolean'

assert.strictEqual(or(true)(false), true)
assert.strictEqual(or(false)(false), false)

Added in v0.4.0

xor

Returns true if one argument is true and the other is false, else false. Equivalent to exclusive logical disjunction.

Signature

export declare const xor: (x: boolean) => Endomorphism<boolean>

xor :: boolean -> Endomorphism boolean

Example

import { xor } from 'fp-ts-std/Boolean'

assert.strictEqual(xor(true)(false), true)
assert.strictEqual(xor(true)(true), false)

Added in v0.4.0