Objective

This is a minimalistic library aimed to reuse logic on HashTables mapping, that i use over and over i.e. consuming API results to pass to Twig views.

Makes easy to do filtering/renaming of unwanted keys through simple dictionary of keys of source to target. Through callbacks supports any transformation, and passing it another callable or another instance of HashMapper, pretty complex transformation of associative arrays, a.k.a as Hashmaps for friends.

use function Apantle\HashMapper\hashMapper;

$target = hashMapper($specs, $options)($source);

Installation

You can install the package via composer:

composer require apantle/hashmapper

Simple key mapping

Change one key in input, only output that in target.

Input	Mapper	Output
['origin' => 'Africa'];	hashMapper(['origin' => 'roots])	['roots' => 'Africa']

Callback key mapping

For somewhat complex transforms, you can use a function that will receive as arguments:

• the value of the source hashmap specified at key:
• the whole hashmap if you need other values of it

assert(hashMapper([
    'place' => 'Caso CIDH',
    'date' => [
        'fecha',
        function($date, $source) {
            extract($date);
            $date = date_create_from_format('Y/m/d', "{$year}/{$month}/{$day}");
            return $date->format('Y-m-d');
        }
    ],
])([
    'date' => [
        'year' => 2006,
        'month' => 5,
        'day' => 4,
    ],
    'place' => 'San Salvador Atenco',
]) === [
    'Caso CIDH' => 'San Salvador Atenco',
    'fecha' => '2006-05-04'
]);

Use another HashMapper

If you have a complex subkey that is not easily mapped with a simple function, you could use another HashMapper with the spec for that subkey, as the mapper for that key.

assert(hashMapper([
    'sourceKey' => hashMapper([ 'value' => 'legend' ])
])([
    'sourceKey' => [
        'value' => 'to pass to HashMapper',
        'ignored' => 'it should not appear'
    ],
]) === [
    'sourceKey => [
        'legend' => 'to pass to HashMapper'
    ]
]);

Spread Operator Mapping with Callable

If you want to take a key with subkeys of the source and spread it (copy the dictionary of key and values it contains) on the target hashmap, you can pass a tuple with the string '...' as the target key, and your chosen callable.

assert(hashMapper([
    'wp:term' => ['...', 'Apantle\FunPHP\identity']
])([
    'wp:term' => [
         'id' => 31925,
         'link' => 'http://example.com/category/test-term/',
         'name' => 'Test term',
         'slug' => 'test-term',
         'taxonomy' => 'category',
    ],
    'ignored' => 'right'
]) === [
     'id' => 31925,
     'link' => 'http://example.com/category/test-term/',
     'name' => 'Test term',
     'slug' => 'test-term',
     'taxonomy' => 'category',
]);

Implicit spread (not specifying '...' key)

If you need all the dictionaries inside top level keys be spread into the target, rather than writing your mapping spec as a tuple, you can give it only a callable, specifying the option implicitSpread => true in the constructor to the Mapper functor.

assert(hashMaper(
    [
        'wp:term' => compose('Apantle\FunPHP\head', 'Apantle\FunPHP\identity'),
    ],
    [
        'implicitSpread' => true
    ]
)([
    'wp:term' => [
        [
            'id' => 31925,
            'link' => 'http://example.com/category/test-term/',
            'name' => 'Test term',
            'slug' => 'test-term',
            'taxonomy' => 'category',
        ]
    ],
]) === [
    'id' => 31925,
    'link' => 'http://example.com/category/test-term/',
    'name' => 'Test term',
    'slug' => 'test-term',
    'taxonomy' => 'category',
]);

Call a HashMapper as Functor object

For better reuse, now offers through the __invoke magic, a simpler way to use it to map a collection of associative arrays, as array_map, array_reduce or Collection::map (from Illuminate\Support).

Reuse a HashMapper to transform an array of associative arrays

Instead of using the HashMapper as the function for array_map or Collection::map, you can use our own helper, that applies the same set of transformations to every array passed.

$collectionTransformed = collection(hashMapper($specs))($arrayOfAssociativeArrays);

See issue:1 for more complete examples in test sources.