Predicate overview

Various functions to aid in working with predicates. You may also find the Boolean module relevant.

Added in v0.12.0

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Table of contents

• 3 Functions
  • allPass
  • anyPass
  • nonePass

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3 Functions

allPass

Given an array of predicates, returns a predicate that returns true if the argument passes all of the predicates.

Signature

export declare const allPass: <A>(fs: Predicate<A>[]) => Predicate<A>

allPass :: Array (Predicate a) -> Predicate a

Example

import { allPass } from 'fp-ts-std/Predicate'
import { Predicate } from 'fp-ts/Predicate'

const gt3: Predicate<number> = (n) => n > 3
const lt7: Predicate<number> = (n) => n < 7
const even: Predicate<number> = (n) => n % 2 === 0

assert.strictEqual(allPass([gt3, lt7, even])(4), true)
assert.strictEqual(allPass([gt3, lt7, even])(5), false)

Added in v0.12.0

anyPass

Given an array of predicates, returns a predicate that returns true if the argument passes any of the predicates.

Signature

export declare const anyPass: <A>(fs: Predicate<A>[]) => Predicate<A>

anyPass :: Array (Predicate a) -> Predicate a

Example

import { anyPass } from 'fp-ts-std/Predicate'
import { Predicate } from 'fp-ts/Predicate'

const lt3: Predicate<number> = (n) => n < 3
const gt7: Predicate<number> = (n) => n > 7
const even: Predicate<number> = (n) => n % 2 === 0

assert.strictEqual(anyPass([lt3, gt7, even])(4), true)
assert.strictEqual(anyPass([lt3, gt7, even])(5), false)

Added in v0.12.0

nonePass

Given an array of predicates, returns a predicate that returns true if the argument passes none of the predicates.

Signature

export declare const nonePass: <A>(fs: Predicate<A>[]) => Predicate<A>

nonePass :: Array (Predicate a) -> Predicate a

Example

import { nonePass } from 'fp-ts-std/Predicate'
import { Predicate } from 'fp-ts/Predicate'

const lt3: Predicate<number> = (n) => n < 3
const gt7: Predicate<number> = (n) => n > 7
const even: Predicate<number> = (n) => n % 2 === 0

assert.strictEqual(nonePass([lt3, gt7, even])(4), false)
assert.strictEqual(nonePass([lt3, gt7, even])(5), true)

Added in v0.12.0