Laravel 5 Collections: Convert Collection Elements Into Object Instances With mapInto

The mapInto method is similar to the transform method in that allows you to quickly convert, or project, the contents of the collection to a new type. However, instead of building up the resulting type instance yourself, the mapInto method creates a new instance of the specified class and supplies each collection element's value and key as the arguments to the type's constructor.

#Signature

1public function mapInto(
2    $class
3);

#Example Use

In the following example, we will take advantage of The Open Movie Database (OMDb) API (learn more about this API and get an API key at https://www.omdbapi.com/) to retrieve information above movie titles. We will do this with the following API wrapper class:

The app/Movie.php Class:

 1class Movie {
 2 
 3    /**
 4     * The title of the movie.
 5     *
 6     * @var string
 7     */
 8    protected $title = '';
 9 
10    /**
11     * The OMDB API key.
12     *
13     * @var string
14     */
15    private $omdbApiKey = '';
16 
17    /**
18     * The API base URL.
19     *
20     * @var string
21     */
22    private $baseUrl = 'https://www.omdbapi.com/' .
23                       '?t=<TITLE>&apiKey=<KEY>';
24 
25    /**
26     * Indicates whether or the results
27     * have been fetched from the API.
28     *
29     * @var bool
30     */
31    private $retrievedResults = false;
32 
33    /**
34     * The results of the API call.
35     *
36     * @var null|array
37     */
38    private $apiResults = null;
39 
40    public function __construct($title)
41    {
42        $this->title = $title;
43    }
44 
45    /**
46     * Gets the API URL for the configured
47     * key and movie title.
48     *
49     * @return string
50     */
51    private function getUrl() {
52        return strtr($this->baseUrl, [
53            '<TITLE>' => $this->title,
54            '<KEY>'   => $this->omdbApiKey
55        ]);
56    }
57 
58    /**
59     * Retrieves the API results if they
60     * have not already been fetched.
61     */
62    private function checkResults() {
63        if ($this->retrievedResults === false) {
64            $apiResponse = with(new GuzzleHttp\Client)
65                    ->get($this->getUrl());
66 
67            $this->apiResults = json_decode(
68              $apiResponse->getBody(), true
69            );
70 
71            $this->retrievedResults = true;
72        }
73    }
74 
75    function __get($name)
76    {
77        // This will let us "lazy-load" the API results.
78        if ($this->apiResults == null ||
79            array_key_exists(
80                $name,
81                $this->apiResults) === false) {
82            return null;
83        }
84 
85        return $this->apiResults[$name];
86    }
87 
88}

While the Movie class may look complicated, we are simply issuing a GET request to the OMDb API and providing a proxy to the API results. We can use the mapInto collection method to convert a collection of movie titles into a Movie instance which will let us gather more information about each of the movies:

1$movies = collect([
2    'The Great Outdoors',
3    'Uncle Buck'
4])->mapInto(Movie::class)->each(function ($movie) {
5   echo $movie->Title . ' ('. $movie->Year, ')<br />';
6});

After the above code has executed in a browser, we would see results similar to the following:

1The Great Outdoors (1988)
2Uncle Buck (1989)

∎