php array diff recursive

php

function diffRecursive($from, $to, $deleteFlag = false)
{
    $diffs = [];
    foreach ($from as $key => $value) {
        if (array_key_exists($key, $to)) {
            if (is_array($value)) {
                $recursiveDiff = diffRecursive($value, $to[$key], $deleteFlag);
                if (! empty($recursiveDiff)) {
                    $diffs[$key] = $recursiveDiff;
                }                
            } else {
                if ($value != $to[$key] && ! $deleteFlag) {
                    $diffs[$key] = 'modify';
                }
            }
        } else {
            if ($deleteFlag) {
                $diffs[$key] = 'delete';
            } else {
                $diffs[$key] = 'add';
            }
        }
    }

    return $diffs;
}


$a = [
    'a' => [
        'key1' => 1,
        'key2' => 2,
    ],

    'b'=> [
        'bkey1' => [
            'bbkey1' => 'bb1',
            'bbkey2' => 'bb2',
        ]
    ]
];

$b = [
    'a' => [
        'key1' => 2,
        'key3' => 2,
    ],

    'b'=> [
        'bkey1' => [
            'bbkey1' => 'bb1',
            'bbkey2' => 'bb2',
        ]
    ]
];

$s1 = diffRecursive($a, $b);
var_dump($s1);

$s2 = diffRecursive($b, $a, true);

var_dump($s2);