Overview

The Setoid type class represents types which support decidable equality.

Instances must satisfy the following laws:

1. Reflexivity: S.equals(a, a) === true
2. Symmetry: S.equals(a, b) === S.equals(b, a)
3. Transitivity: if S.equals(a, b) === true and S.equals(b, c) === true, then S.equals(a, c) === true

See Getting started with fp-ts: Setoid

Table of contents

• Setoid (interface)
• setoidBoolean (constant)
• setoidDate (constant)
• setoidNumber (constant)
• setoidString (constant)
• contramap (function)
• fromEquals (function)
• getArraySetoid (function)
• getProductSetoid (function)
• getRecordSetoid (function)
• getStructSetoid (function)
• getTupleSetoid (function)
• strictEqual (function)

Setoid (interface)

Signature

export interface Setoid<A> {
  readonly equals: (x: A, y: A) => boolean
}

Added in v1.0.0

setoidBoolean (constant)

Signature

export const setoidBoolean: Setoid<boolean> = ...

Added in v1.0.0

setoidDate (constant)

Signature

export const setoidDate: Setoid<Date> = ...

Added in v1.4.0

setoidNumber (constant)

Signature

export const setoidNumber: Setoid<number> = ...

Added in v1.0.0

setoidString (constant)

Signature

export const setoidString: Setoid<string> = ...

Added in v1.0.0

contramap (function)

Returns the Setoid corresponding to the partitions of B induced by f

Signature

export const contramap = <A, B>(f: (b: B) => A, fa: Setoid<A>): Setoid<B> => ...

Added in v1.2.0

fromEquals (function)

Signature

export const fromEquals = <A>(equals: (x: A, y: A) => boolean): Setoid<A> => ...

Added in v1.14.0

getArraySetoid (function)

Signature

export const getArraySetoid = <A>(S: Setoid<A>): Setoid<Array<A>> => ...

Added in v1.0.0

getProductSetoid (function)

Use getTupleSetoid instead

Signature

export const getProductSetoid = <A, B>(SA: Setoid<A>, SB: Setoid<B>): Setoid<[A, B]> => ...

Added in v1.0.0

getRecordSetoid (function)

Use getStructSetoid instead

Signature

export const getRecordSetoid = <O extends { [key: string]: any }>(
  setoids: { [K in keyof O]: Setoid<O[K]> }
): Setoid<O> => ...

Added in v1.0.0

getStructSetoid (function)

Signature

export const getStructSetoid = <O extends { [key: string]: any }>(
  setoids: { [K in keyof O]: Setoid<O[K]> }
): Setoid<O> => ...

Added in v1.14.2

getTupleSetoid (function)

Signature

export const getTupleSetoid = <A, B>(SA: Setoid<A>, SB: Setoid<B>): Setoid<[A, B]> => ...

Added in v1.14.2

strictEqual (function)

Signature

export const strictEqual = <A>(a: A, b: A): boolean => ...

Added in v1.0.0