Maybe code.

gistfile1.txt

function Maybe(x) {
  this.x = x;
  this.isEmpty = x == null || x == undefined;
}
 
 
Maybe.prototype.map = function(f) {
  //composition operator anyone?
  return this.chain(function(x) {
  return Maybe.of(f(x));
  });
}
 
Maybe.prototype.chain = function(f) {
    if(this.isEmpty) return this;
    return f(this.x);
} 
 
Maybe.of = function(x) {
    return new Maybe(x);
};