Scala Option in JavaScript

gistfile1.js

var MyOption, Option;

Array.prototype.filter = function(f) {
  var x, _i, _len, _results;
  _results = [];
  for (_i = 0, _len = this.length; _i < _len; _i++) {
    x = this[_i];
    if (f(x)) {
      _results.push(x);
    }
  }
  return _results;
};

Number.prototype.filter = function(f) {
  return [this.valueOf()].filter(f);
};

String.prototype.filter = Number.prototype.filter;

Object.prototype.filter = function(f) {
  if (f(this)) {
    return this;
  } else {
    return null;
  }
};

Array.prototype.foreach = function(f) {
  var x, _i, _len, _results;
  _results = [];
  for (_i = 0, _len = this.length; _i < _len; _i++) {
    x = this[_i];
    _results.push(f(x));
  }
  return _results;
};

Number.prototype.foreach = function(f) {
  return [this.valueOf()].foreach(f);
};

String.prototype.foreach = Number.prototype.foreach;

Object.prototype.foreach = function(f) {
  if (this) {
    return f(this);
  } else {
    return null;
  }
};

Array.prototype.exists = function(f) {
  var item, _i, _len;
  for (_i = 0, _len = this.length; _i < _len; _i++) {
    item = this[_i];
    if (f(item)) {
      return true;
    }
  }
  return false;
};

Number.prototype.exists = function(f) {
  return [this.valueOf()].exists(f);
};

String.prototype.exists = Number.prototype.exists;

Object.prototype.exists = function(f) {
  return f(this);
};

Array.prototype.map = function(f) {
  var x, _i, _len, _results;
  _results = [];
  for (_i = 0, _len = this.length; _i < _len; _i++) {
    x = this[_i];
    _results.push(f(x));
  }
  return _results;
};

Number.prototype.map = function(f) {
  return [this.valueOf()].map(f);
};

String.prototype.map = Number.prototype.map;

Object.prototype.map = function(f) {
  if (this) {
    return f(this);
  } else {
    return null;
  }
};

MyOption = (function() {
  function MyOption(item) {
    this.item = item;
  }
  MyOption.prototype.getOrElse = function(def) {
    if (this.item != null) {
      return this.item;
    } else {
      return def;
    }
  };
  MyOption.prototype.exists = function(f) {
    var _ref;
    return (_ref = this.item) != null ? _ref.exists(f) : void 0;
  };
  MyOption.prototype.get = function() {
    return this.item;
  };
  MyOption.prototype.isDefined = function() {
    return this.item != null;
  };
  MyOption.prototype.isEmpty = function() {
    return !(this.item != null);
  };
  MyOption.prototype.filter = function(f) {
    var _ref;
    return (_ref = this.item) != null ? _ref.filter(f) : void 0;
  };
  MyOption.prototype.foreach = function(f) {
    var _ref;
    return (_ref = this.item) != null ? _ref.foreach(f) : void 0;
  };
  MyOption.prototype.map = function(f) {
    var _ref;
    return (_ref = this.item) != null ? _ref.map(f) : void 0;
  };
  MyOption.prototype.orElse = function(def) {
    if (this.item != null) {
      return this;
    } else {
      return def;
    }
  };
  MyOption.prototype.orNull = function() {
    if (this.item != null) {
      return this;
    } else {
      return null;
    }
  };
  return MyOption;
})();

Option = function(x) {
  return new MyOption(x);
};

$(function() {
  var x, y;
  x = "Yes";
  y = null;
  alert(Option(x).getOrElse("No"));
  return alert(Option(y).getOrElse("No"));
});

Came looking for a Javascript Option, and was amused to find you here first Landon!

Suggestions:

• support for Some & None;
• method equals to compare Options;
• treat undefined as null so it is None too;