maybe.functional.js

var person = {
  name: 'Homer Simpson',
  address: {
    street: '123 Fake St.',
    city: 'Springfield'
  }
};

//Complete Imperative
if (person != null && person['address'] != null) {
  var state = person['address']['state'];
  if (state != null) {
    console.log(state);
  }
  else {
    console.log('State unknown');
  }
}

//Imperative with Functional features
var state = person && person['address'] && person['address']['state'];
console.log(state || 'State unknown');

//Functional direct
console.log(_.get(person, 'address.state', 'State unknown'));

//Functional comonad
console.log(
  _.chain(person)
  .result('address')
  .result('state', 'State unknown')
  .value()
);

//Functional monad
console.log(
  Maybe(person)
  .bind(p => p['address'])
  .bind(a => p['state'])
  .maybe('State unknown', s => s)
);