Functional programming: Combining map with reduce

combine-map-with-reduce.js

function() {
	var movieLists = [
		{
			name: "New Releases",
			videos: [
				{
					"id": 70111470,
					"title": "Die Hard",
					"boxarts": [
						{ width: 150, height:200, url:"http://cdn-0.nflximg.com/images/2891/DieHard150.jpg" },
						{ width: 200, height:200, url:"http://cdn-0.nflximg.com/images/2891/DieHard200.jpg" }
					],
					"url": "http://api.netflix.com/catalog/titles/movies/70111470",
					"rating": 4.0,
					"bookmark": []
				},
				{
					"id": 654356453,
					"title": "Bad Boys",
					"boxarts": [
						{ width: 200, height:200, url:"http://cdn-0.nflximg.com/images/2891/BadBoys200.jpg" },
						{ width: 140, height:200, url:"http://cdn-0.nflximg.com/images/2891/BadBoys140.jpg" }

					],
					"url": "http://api.netflix.com/catalog/titles/movies/70111470",
					"rating": 5.0,
					"bookmark": [{ id:432534, time:65876586 }]
				}
			]
		},
		{
			name: "Thrillers",
			videos: [
				{
					"id": 65432445,
					"title": "The Chamber",
					"boxarts": [
						{ width: 130, height:200, url:"http://cdn-0.nflximg.com/images/2891/TheChamber130.jpg" },
						{ width: 200, height:200, url:"http://cdn-0.nflximg.com/images/2891/TheChamber200.jpg" }
					],
					"url": "http://api.netflix.com/catalog/titles/movies/70111470",
					"rating": 4.0,
					"bookmark": []
				},
				{
					"id": 675465,
					"title": "Fracture",
					"boxarts": [
						{ width: 200, height:200, url:"http://cdn-0.nflximg.com/images/2891/Fracture200.jpg" },
						{ width: 120, height:200, url:"http://cdn-0.nflximg.com/images/2891/Fracture120.jpg" },
						{ width: 300, height:200, url:"http://cdn-0.nflximg.com/images/2891/Fracture300.jpg" }
					],
					"url": "http://api.netflix.com/catalog/titles/movies/70111470",
					"rating": 5.0,
					"bookmark": [{ id:432534, time:65876586 }]
				}
			]
		}
	];


	// Use one or more concatMap, map, and reduce calls to create an array with the following items (order doesn't matter)
	// [
	//	 {"id": 675465,"title": "Fracture","boxart":"http://cdn-0.nflximg.com/images/2891/Fracture120.jpg" },
	//	 {"id": 65432445,"title": "The Chamber","boxart":"http://cdn-0.nflximg.com/images/2891/TheChamber130.jpg" },
	//	 {"id": 654356453,"title": "Bad Boys","boxart":"http://cdn-0.nflximg.com/images/2891/BadBoys140.jpg" },
	//	 {"id": 70111470,"title": "Die Hard","boxart":"http://cdn-0.nflximg.com/images/2891/DieHard150.jpg" }
	// ];

	return movieLists.
		concatMap(function(movieList) {
      
      return movieList.videos.concatMap(function(video) {
        
        return video.boxarts.reduce(function(acc, curr) {
          if (curr.width * curr.height < acc.width * acc.height) {
           return curr; 
          } else {
           return acc; 
          }
        }).map(function(boxart) {
          return { id: video.id, title: video.title, boxart: boxart.url }; 
        }); // [{id, title, boxart}]
        
      }); // [{id, title, boxart}]
      
		}) // [{id, title, boxart}]

}