Skip to main content Link Search Menu Expand Document (external link)
effect

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 v2.0.0

Table of contents

combinators

array

Creates a new Equivalence for an array of values based on a given Equivalence for the elements of the array.

Signature

export declare const array: <A>(item: Equivalence<A>) => Equivalence<readonly A[]>

Added in v2.0.0

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>>>(
  fields: R
) => Equivalence<{ readonly [K in keyof R]: [R[K]] extends [Equivalence<infer A>] ? A : never }>

Added in v2.0.0

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>[]>(
  ...elements: T
) => Equivalence<Readonly<{ [I in keyof T]: [T[I]] extends [Equivalence<infer A>] ? A : never }>>

Added in v2.0.0

combining

all

Signature

export declare const all: <A>(collection: Iterable<Equivalence<A>>) => Equivalence<readonly A[]>

Added in v2.0.0

combine

Signature

export declare const combine: {
  <A>(that: Equivalence<A>): (self: Equivalence<A>) => Equivalence<A>
  <A>(self: Equivalence<A>, that: Equivalence<A>): Equivalence<A>
}

Added in v2.0.0

combineAll

Signature

export declare const combineAll: <A>(collection: Iterable<Equivalence<A>>) => Equivalence<A>

Added in v2.0.0

combineMany

Signature

export declare const combineMany: {
  <A>(collection: Iterable<Equivalence<A>>): (self: Equivalence<A>) => Equivalence<A>
  <A>(self: Equivalence<A>, collection: Iterable<Equivalence<A>>): Equivalence<A>
}

Added in v2.0.0

product

Signature

export declare const product: {
  <B>(that: Equivalence<B>): <A>(self: Equivalence<A>) => Equivalence<readonly [A, B]>
  <A, B>(self: Equivalence<A>, that: Equivalence<B>): Equivalence<readonly [A, B]>
}

Added in v2.0.0

productMany

Signature

export declare const productMany: <A>(
  self: Equivalence<A>,
  collection: Iterable<Equivalence<A>>
) => Equivalence<readonly [A, ...A[]]>

Added in v2.0.0

constructors

make

Signature

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

Added in v2.0.0

strict

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

Signature

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

Added in v2.0.0

instances

Date

Signature

export declare const Date: Equivalence<Date>

Added in v2.0.0

bigint

Signature

export declare const bigint: Equivalence<bigint>

Added in v2.0.0

boolean

Signature

export declare const boolean: Equivalence<boolean>

Added in v2.0.0

number

Signature

export declare const number: Equivalence<number>

Added in v2.0.0

string

Signature

export declare const string: Equivalence<string>

Added in v2.0.0

symbol

Signature

export declare const symbol: Equivalence<symbol>

Added in v2.0.0

mapping

mapInput

Signature

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

Added in v2.0.0

type class

Equivalence (interface)

Signature

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

Added in v2.0.0

type lambdas

EquivalenceTypeLambda (interface)

Signature

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

Added in v2.0.0