271 lines
6.6 KiB
TypeScript
271 lines
6.6 KiB
TypeScript
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/**
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* `Monoid` extends the power of `Semigroup` by providing an additional `empty` value.
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*
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* ```ts
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* interface Semigroup<A> {
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* readonly concat: (x: A, y: A) => A
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* }
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*
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* interface Monoid<A> extends Semigroup<A> {
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* readonly empty: A
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* }
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* ```
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*
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* This `empty` value should be an identity for the `concat` operation, which means the following equalities hold for any choice of `x`.
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*
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* ```ts
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* concat(x, empty) = concat(empty, x) = x
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* ```
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*
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* Many types that form a `Semigroup` also form a `Monoid`, such as `number`s (with `0`) and `string`s (with `''`).
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*
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* ```ts
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* import { Monoid } from 'fp-ts/Monoid'
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*
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* const monoidString: Monoid<string> = {
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* concat: (x, y) => x + y,
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* empty: ''
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* }
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* ```
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*
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* *Adapted from https://typelevel.org/cats*
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*
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* @since 2.0.0
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*/
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import { Bounded } from './Bounded'
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import { Endomorphism } from './Endomorphism'
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import { ReadonlyRecord } from './ReadonlyRecord'
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import * as Se from './Semigroup'
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/**
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* @category model
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* @since 2.0.0
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*/
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export interface Monoid<A> extends Se.Semigroup<A> {
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readonly empty: A
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}
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/**
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* Get a monoid where `concat` will return the minimum, based on the provided bounded order.
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*
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* The `empty` value is the `top` value.
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*
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* @example
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* import * as N from 'fp-ts/number'
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* import * as M from 'fp-ts/Monoid'
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*
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* const M1 = M.min(N.Bounded)
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*
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* assert.deepStrictEqual(M1.concat(1, 2), 1)
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*
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* @category constructors
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* @since 2.10.0
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*/
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export declare const min: <A>(B: Bounded<A>) => Monoid<A>
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/**
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* Get a monoid where `concat` will return the maximum, based on the provided bounded order.
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*
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* The `empty` value is the `bottom` value.
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*
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* @example
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* import * as N from 'fp-ts/number'
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* import * as M from 'fp-ts/Monoid'
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*
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* const M1 = M.max(N.Bounded)
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*
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* assert.deepStrictEqual(M1.concat(1, 2), 2)
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*
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* @category constructors
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* @since 2.10.0
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*/
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export declare const max: <A>(B: Bounded<A>) => Monoid<A>
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/**
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* The dual of a `Monoid`, obtained by swapping the arguments of `concat`.
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*
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* @example
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* import { reverse } from 'fp-ts/Monoid'
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* import * as S from 'fp-ts/string'
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*
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* assert.deepStrictEqual(reverse(S.Monoid).concat('a', 'b'), 'ba')
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*
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* @since 2.10.0
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*/
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export declare const reverse: <A>(M: Monoid<A>) => Monoid<A>
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/**
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* Given a struct of monoids returns a monoid for the struct.
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*
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* @example
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* import { struct } from 'fp-ts/Monoid'
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* import * as N from 'fp-ts/number'
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*
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* interface Point {
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* readonly x: number
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* readonly y: number
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* }
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*
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* const M = struct<Point>({
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* x: N.MonoidSum,
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* y: N.MonoidSum
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* })
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*
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* assert.deepStrictEqual(M.concat({ x: 1, y: 2 }, { x: 3, y: 4 }), { x: 4, y: 6 })
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*
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* @since 2.10.0
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*/
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export declare const struct: <A>(monoids: { [K in keyof A]: Monoid<A[K]> }) => Monoid<{
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readonly [K_1 in keyof A]: A[K_1]
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}>
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/**
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* Given a tuple of monoids returns a monoid for the tuple.
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*
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* @example
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* import { tuple } from 'fp-ts/Monoid'
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* import * as B from 'fp-ts/boolean'
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* import * as N from 'fp-ts/number'
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* import * as S from 'fp-ts/string'
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*
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* const M1 = tuple(S.Monoid, N.MonoidSum)
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* assert.deepStrictEqual(M1.concat(['a', 1], ['b', 2]), ['ab', 3])
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*
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* const M2 = tuple(S.Monoid, N.MonoidSum, B.MonoidAll)
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* assert.deepStrictEqual(M2.concat(['a', 1, true], ['b', 2, false]), ['ab', 3, false])
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*
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* @since 2.10.0
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*/
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export declare const tuple: <A extends readonly unknown[]>(
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...monoids: { [K in keyof A]: Monoid<A[K]> }
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) => Monoid<Readonly<A>>
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/**
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* Given a sequence of `as`, concat them and return the total.
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*
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* If `as` is empty, return the monoid `empty` value.
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*
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* @example
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* import { concatAll } from 'fp-ts/Monoid'
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* import * as N from 'fp-ts/number'
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*
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* assert.deepStrictEqual(concatAll(N.MonoidSum)([1, 2, 3]), 6)
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* assert.deepStrictEqual(concatAll(N.MonoidSum)([]), 0)
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*
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* @since 2.10.0
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*/
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export declare const concatAll: <A>(M: Monoid<A>) => (as: readonly A[]) => A
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/**
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* Use [`Monoid`](./void.ts.html#monoid) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const monoidVoid: Monoid<void>
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/**
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* Use [`tuple`](#tuple) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const getTupleMonoid: <T extends ReadonlyArray<Monoid<any>>>(
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...monoids: T
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) => Monoid<{
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[K in keyof T]: T[K] extends Se.Semigroup<infer A> ? A : never
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}>
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/**
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* Use [`struct`](#struct) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const getStructMonoid: <O extends ReadonlyRecord<string, any>>(monoids: {
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[K in keyof O]: Monoid<O[K]>
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}) => Monoid<O>
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/**
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* Use [`reverse`](#reverse) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const getDualMonoid: <A>(M: Monoid<A>) => Monoid<A>
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/**
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* Use [`max`](#max) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const getJoinMonoid: <A>(B: Bounded<A>) => Monoid<A>
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/**
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* Use [`min`](#min) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const getMeetMonoid: <A>(B: Bounded<A>) => Monoid<A>
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/**
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* Use [`concatAll`](#concatall) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const fold: <A>(M: Monoid<A>) => (as: readonly A[]) => A
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/**
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* Use [`MonoidAll`](./boolean.ts.html#monoidall) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const monoidAll: Monoid<boolean>
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/**
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* Use [`MonoidAny`](./boolean.ts.html#monoidany) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const monoidAny: Monoid<boolean>
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/**
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* Use [`getMonoid`](./function.ts.html#getmonoid) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const getFunctionMonoid: <M>(M: Monoid<M>) => <A = never>() => Monoid<(a: A) => M>
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/**
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* Use [`getEndomorphismMonoid`](./function.ts.html#getendomorphismmonoid) instead.
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*
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* **Note**. The execution order in [`getEndomorphismMonoid`](./function.ts.html#getendomorphismmonoid) is reversed.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const getEndomorphismMonoid: <A = never>() => Monoid<Endomorphism<A>>
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/**
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* Use [`Monoid`](./string.ts.html#monoid) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const monoidString: Monoid<string>
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/**
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* Use [`MonoidSum`](./number.ts.html#monoidsum) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const monoidSum: Monoid<number>
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/**
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* Use [`MonoidProduct`](./number.ts.html#monoidproduct) instead.
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*
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* @category zone of death
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* @since 2.0.0
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* @deprecated
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*/
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export declare const monoidProduct: Monoid<number>
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