// ES5 version of example

var characters = [

  {name: 'Luke Skywalker', img: 'http://example.com/img/luke.jpg', species: 'human'},

  {name: 'Han Solo', img: 'http://example.com/img/han.jpg', species: 'human'},

  {name: 'Leia Organa', img: 'http://example.com/img/leia.jpg', species: 'human'},

  {name: 'Chewbacca', img: 'http://example.com/img/chewie.jpg', species: 'wookie'}

];

​

var humans = function(data) {

  return data.filter(function(character) {

    return character.species === 'human';

  })

}

​

var images = function(data) {

  return data.map(function(character) {

    return character.img;

  })

}

​

function compose(func1, func2) {

  return function(data) {

    return func2(func1(data));

  };

}

​

var displayCharacterImages = compose(humans, images); 

​

console.log(displayCharacterImages(characters));