example

var peeps = { hugh: { name: 'hugh jackson' } }
var titleCase = function(str){ 
  return str.split(' ').map(function(str){ return str.substr(0, 1).toUpperCase() + str.substr(1) }).join(' ')
}

var val = maybe(peeps)
              .map(function(peeps){ return peeps.tahir })
              .map(function(peep){ return peep.name })
              .map(titleCase)
              .getOrElse('couldn\'t find person')

val //= couldn't find person

var val2 = maybe(peeps)
              .map(function(peeps){ return peeps.hugh })
              .map(function(peep){ return peep.name })
              .map(titleCase)
              .getOrElse('couldn\'t find person')

val2 //= Hugh Jackson

maybe-monad.js

function maybe(value) {
  var obj = null;
  function isEmpty() { return value === undefined || value === null }
  function nonEmpty() { return !isEmpty() }
  obj = {
    map: function (f) { return isEmpty() ? obj : maybe(f(value)) },
    getOrElse: function (n) { return isEmpty() ? n : value },
    isEmpty: isEmpty,
    nonEmpty: nonEmpty
  }
  return obj;
}