@andrwj/fp/maybe.js

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.lift = exports.Nothing = exports.Just = exports.Maybe = void 0;

var R = _interopRequireWildcard(require("ramda"));

function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { var desc = Object.defineProperty && Object.getOwnPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : {}; if (desc.get || desc.set) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } } newObj["default"] = obj; return newObj; } }

function _typeof(obj) { if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") { _typeof = function _typeof(obj) { return typeof obj; }; } else { _typeof = function _typeof(obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; }; } return _typeof(obj); }

function _possibleConstructorReturn(self, call) { if (call && (_typeof(call) === "object" || typeof call === "function")) { return call; } return _assertThisInitialized(self); }

function _assertThisInitialized(self) { if (self === void 0) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return self; }

function _getPrototypeOf(o) { _getPrototypeOf = Object.setPrototypeOf ? Object.getPrototypeOf : function _getPrototypeOf(o) { return o.__proto__ || Object.getPrototypeOf(o); }; return _getPrototypeOf(o); }

function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function"); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, writable: true, configurable: true } }); if (superClass) _setPrototypeOf(subClass, superClass); }

function _setPrototypeOf(o, p) { _setPrototypeOf = Object.setPrototypeOf || function _setPrototypeOf(o, p) { o.__proto__ = p; return o; }; return _setPrototypeOf(o, p); }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }

var Maybe =
/*#__PURE__*/
function () {
  function Maybe(v) {
    _classCallCheck(this, Maybe);

    this._value = v;
  }

  _createClass(Maybe, [{
    key: "isNothing",
    get: function get() {
      return false;
    }
  }, {
    key: "isJust",
    get: function get() {
      return true;
    }
  }], [{
    key: "just",
    value: function just(v) {
      return new Just(v);
    }
  }, {
    key: "nothing",
    value: function nothing() {
      return new Nothing();
    }
  }, {
    key: "fromNullable",
    value: function fromNullable(v) {
      return [null, undefined].some(function (_) {
        return Object.is(v, _);
      }) ? Maybe.nothing(v) : Maybe.just(v);
    }
  }, {
    key: "of",
    value: function of(v) {
      return just(v);
    }
  }]);

  return Maybe;
}();

exports.Maybe = Maybe;

var Just =
/*#__PURE__*/
function (_Maybe) {
  _inherits(Just, _Maybe);

  function Just(v) {
    _classCallCheck(this, Just);

    return _possibleConstructorReturn(this, _getPrototypeOf(Just).call(this, v));
  }

  _createClass(Just, [{
    key: "map",
    value: function map(f) {
      return Maybe.fromNullable(f(this._value));
    }
  }, {
    key: "getOrElse",
    value: function getOrElse() {
      return this._value;
    }
  }, {
    key: "filter",
    value: function filter(f) {
      return Maybe.fromNullable(f(this._value)) ? this._value : null;
    }
  }, {
    key: "chain",
    value: function chain(f) {
      return f(this._value);
    }
  }, {
    key: "toString",
    value: function toString() {
      return "Maybe.Just(".concat(this._value, ")");
    }
  }, {
    key: "value",
    get: function get() {
      return this._value;
    }
  }]);

  return Just;
}(Maybe);

exports.Just = Just;

var Nothing =
/*#__PURE__*/
function (_Maybe2) {
  _inherits(Nothing, _Maybe2);

  function Nothing(v) {
    _classCallCheck(this, Nothing);

    return _possibleConstructorReturn(this, _getPrototypeOf(Nothing).call(this, v));
  }

  _createClass(Nothing, [{
    key: "map",
    value: function map(f) {
      return this;
    }
  }, {
    key: "getOrElse",
    value: function getOrElse(v) {
      return v;
    }
  }, {
    key: "filter",
    value: function filter(f) {
      return null;
    }
  }, {
    key: "chain",
    value: function chain(f) {
      return this;
    }
  }, {
    key: "toString",
    value: function toString() {
      return "Maybe.Nothing";
    }
  }, {
    key: "value",
    get: function get() {
      throw new TypeError("It's nothing. You can not get from it");
    }
  }, {
    key: "isNothing",
    get: function get() {
      return true;
    }
  }, {
    key: "isJust",
    get: function get() {
      return false;
    }
  }]);

  return Nothing;
}(Maybe);

exports.Nothing = Nothing;
var lift = R.curry(function (f, value) {
  return Maybe.fromNullable(value).map(f);
});
exports.lift = lift;