Magma overview
A Magma is a pair (A, concat) in which A is a non-empty set and concat is a binary operation on A
See Semigroup for some instances.
Added in v2.0.0
Table of contents
model
Magma (interface)
Signature
export interface Magma<A> {
readonly concat: (x: A, y: A) => A
}
Added in v2.0.0
utils
concatAll
Given a sequence of as, concat them and return the total.
If as is empty, return the provided startWith value.
Signature
export declare const concatAll: <A>(M: Magma<A>) => (startWith: A) => (as: readonly A[]) => A
Example
import { concatAll } from 'fp-ts/Magma'
import * as N from 'fp-ts/number'
const subAll = concatAll(N.MagmaSub)(0)
assert.deepStrictEqual(subAll([1, 2, 3]), -6)
Added in v2.11.0
endo
Signature
export declare const endo: <A>(f: Endomorphism<A>) => (M: Magma<A>) => Magma<A>
Added in v2.11.0
filterFirst
Signature
export declare const filterFirst: <A>(predicate: Predicate<A>) => (M: Magma<A>) => Magma<A>
Added in v2.11.0
filterSecond
Signature
export declare const filterSecond: <A>(predicate: Predicate<A>) => (M: Magma<A>) => Magma<A>
Added in v2.11.0
reverse
The dual of a Magma, obtained by swapping the arguments of concat.
Signature
export declare const reverse: <A>(M: Magma<A>) => Magma<A>
Example
import { reverse, concatAll } from 'fp-ts/Magma'
import * as N from 'fp-ts/number'
const subAll = concatAll(reverse(N.MagmaSub))(0)
assert.deepStrictEqual(subAll([1, 2, 3]), 2)
Added in v2.11.0