Equivalence overview

This module provides an implementation of the Equivalence type class, which defines a binary relation that is reflexive, symmetric, and transitive. In other words, it defines a notion of equivalence between values of a certain type. These properties are also known in mathematics as an “equivalence relation”.

Added in v1.0.0

Table of contents

• combinators
  • contramap
  • struct
  • tuple
• constructors
  • make
  • strict
• instances
  • Contravariant
  • Invariant
  • Product
  • SemiProduct
  • bigint
  • boolean
  • getMonoid
  • getSemigroup
  • number
  • string
  • symbol
• type class
  • Equivalence (interface)
• type lambdas
  • EquivalenceTypeLambda (interface)

combinators

contramap

Signature

export declare const contramap: {
  <B, A>(f: (b: B) => A): (self: Equivalence<A>) => Equivalence<B>
  <A, B>(self: Equivalence<A>, f: (b: B) => A): Equivalence<B>
}

Added in v1.0.0

struct

Given a struct of Equivalences returns a new Equivalence that compares values of a struct by applying each Equivalence to the corresponding property of the struct.

Signature

export declare const struct: <R extends Record<string, Equivalence<any>>>(
  predicates: R
) => Equivalence<{ readonly [K in keyof R]: [R[K]] extends [Equivalence<infer A>] ? A : never }>

Added in v1.0.0

tuple

Similar to Promise.all but operates on Equivalences.

[Equivalence<A>, Equivalence<B>, ...] -> Equivalence<[A, B, ...]>

Given a tuple of Equivalences returns a new Equivalence that compares values of a tuple by applying each Equivalence to the corresponding element of the tuple.

Signature

export declare const tuple: <T extends readonly Equivalence<any>[]>(
  ...predicates: T
) => Equivalence<Readonly<{ [I in keyof T]: [T[I]] extends [Equivalence<infer A>] ? A : never }>>

Added in v1.0.0

constructors

make

Signature

export declare const make: <A>(isEquivalent: (self: A, that: A) => boolean) => Equivalence<A>

Added in v1.0.0

strict

Return an Equivalence that uses strict equality (===) to compare values.

Signature

export declare const strict: <A>() => Equivalence<A>

Added in v1.0.0

instances

Contravariant

Signature

export declare const Contravariant: contravariant.Contravariant<EquivalenceTypeLambda>

Added in v1.0.0

Invariant

Signature

export declare const Invariant: invariant.Invariant<EquivalenceTypeLambda>

Added in v1.0.0

Product

Signature

export declare const Product: product_.Product<EquivalenceTypeLambda>

Added in v1.0.0

SemiProduct

Signature

export declare const SemiProduct: semiProduct.SemiProduct<EquivalenceTypeLambda>

Added in v1.0.0

bigint

Signature

export declare const bigint: Equivalence<bigint>

Added in v1.0.0

boolean

Signature

export declare const boolean: Equivalence<boolean>

Added in v1.0.0

getMonoid

Signature

export declare const getMonoid: <A>() => Monoid<Equivalence<A>>

Added in v1.0.0

getSemigroup

Signature

export declare const getSemigroup: <A>() => Semigroup<Equivalence<A>>

Added in v1.0.0

number

Signature

export declare const number: Equivalence<number>

Added in v1.0.0

string

Signature

export declare const string: Equivalence<string>

Added in v1.0.0

symbol

Signature

export declare const symbol: Equivalence<symbol>

Added in v1.0.0

type class

Equivalence (interface)

Signature

export interface Equivalence<A> {
  (self: A, that: A): boolean
}

Added in v1.0.0

type lambdas

EquivalenceTypeLambda (interface)

Signature

export interface EquivalenceTypeLambda extends TypeLambda {
  readonly type: Equivalence<this['Target']>
}

Added in v1.0.0