crocks/core/isMonoid.js

A collection of well known Algebraic Datatypes for your utter enjoyment.

/** @license ISC License (c) copyright 2016 original and current authors */
/** @author Ian Hofmann-Hicks (evil) */

var hasAlg = require('./hasAlg')
var isSemigroup = require('./isSemigroup')

// isMonoid :: a -> Boolean
function isMonoid(m) {
  return isSemigroup(m)
    && (hasAlg('empty', m) || hasAlg('empty', m.constructor))
}

module.exports = isMonoid