Innovenergy_trunk/frontend/node_modules/fp-ts/es6/Magma.js

76 lines
2.2 KiB
JavaScript

/**
* 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](https://gcanti.github.io/fp-ts/modules/Semigroup.ts.html) for some instances.
*
* @since 2.0.0
*/
// -------------------------------------------------------------------------------------
// combinators
// -------------------------------------------------------------------------------------
/**
* The dual of a `Magma`, obtained by swapping the arguments of `concat`.
*
* @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)
*
* @since 2.11.0
*/
export var reverse = function (M) { return ({
concat: function (first, second) { return M.concat(second, first); }
}); };
/**
* @since 2.11.0
*/
export var filterFirst = function (predicate) {
return function (M) { return ({
concat: function (first, second) { return (predicate(first) ? M.concat(first, second) : second); }
}); };
};
/**
* @since 2.11.0
*/
export var filterSecond = function (predicate) {
return function (M) { return ({
concat: function (first, second) { return (predicate(second) ? M.concat(first, second) : first); }
}); };
};
/**
* @since 2.11.0
*/
export var endo = function (f) {
return function (M) { return ({
concat: function (first, second) { return M.concat(f(first), f(second)); }
}); };
};
// -------------------------------------------------------------------------------------
// utils
// -------------------------------------------------------------------------------------
/**
* Given a sequence of `as`, concat them and return the total.
*
* If `as` is empty, return the provided `startWith` value.
*
* @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)
*
* @since 2.11.0
*/
export var concatAll = function (M) {
return function (startWith) {
return function (as) {
return as.reduce(function (a, acc) { return M.concat(a, acc); }, startWith);
};
};
};