@fpjs/overture/dist/cjs/data/maybe.js

A Javascript prelude

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.toMaybe = exports.maybeToArray = exports.fromMaybe = exports.Nothing = exports.Maybe = exports.Just = void 0;
var _base = require("@fpjs/overture/base");
var _functor = require("@fpjs/overture/algebras/functor");
var _setoid = require("@fpjs/overture/algebras/setoid");
var _ord = require("@fpjs/overture/algebras/ord");
const Maybe = exports.Maybe = {
  '@@type': 'Maybe'
};
const self = function () {
  return this;
};
const Nothing = exports.Nothing = {
  '@@type': 'Maybe',
  '@@name': 'Nothing',
  'constructor': Maybe,
  'fantasy-land/map': self,
  'fantasy-land/ap': self,
  'fantasy-land/chain': self,
  'fantasy-land/reduce': (_, z) => z,
  'fantasy-land/equals': y => y.caseOf({
    'Nothing': (0, _base.constant)(true),
    'Just': (0, _base.constant)(false)
  }),
  'fantasy-land/lte': y => y.caseOf({
    'Nothing': (0, _base.constant)(true),
    'Just': (0, _ord.lte)(x)
  }),
  'caseOf': cases => cases['Nothing']()
};
const Just = x => ({
  '@@type': 'Maybe',
  '@@name': 'Just',
  'constructor': Maybe,
  'fantasy-land/map': f => Just(f(x)),
  'fantasy-land/ap': (0, _functor.map)(f => f(x)),
  'fantasy-land/chain': f => f(x),
  'fantasy-land/reduce': (f, z) => f(z, x),
  'fantasy-land/equals': y => y.caseOf({
    'Nothing': (0, _base.constant)(true),
    'Just': (0, _setoid.equals)(x)
  }),
  'fantasy-land/lte': y => y.caseOf({
    'Nothing': (0, _base.constant)(true),
    'Just': (0, _ord.lte)(x)
  }),
  'caseOf': cases => cases['Just'](x)
});
exports.Just = Just;
Maybe['fantasy-land/of'] = Just;
const fromMaybe = def => x => {
  if ((0, _base.type)(x) !== 'Maybe') {
    throw TypeError(`${(0, _base.type)(x)} is not Maybe.`);
  }
  return x.caseOf({
    'Just': _base.id,
    'Nothing': (0, _base.constant)(def)
  });
};
exports.fromMaybe = fromMaybe;
const toMaybe = x => x != null ? Just(x) : Nothing;
exports.toMaybe = toMaybe;
const maybeToArray = x => {
  if ((0, _base.type)(x) !== 'Maybe') {
    throw TypeError(`${(0, _base.type)(x)} is not Maybe.`);
  }
  return x.caseOf({
    'Just': x => [x],
    'Nothing': (0, _base.constant)([])
  });
};
exports.maybeToArray = maybeToArray;