<?php
    $data = array(
    	"fo'o",
    	'bar' => "foo'bar",
    	'foobar' => array(
    		1, 2, 'someObj' => json_decode('{"prop1": "a", "prop2": "b\'c"}')
     	)
    );
    
    function addslashes_extended(&$mixed) {
    	if (is_array($mixed) || is_object($mixed)) {
    		array_walk($mixed, 'addslashes_extended');
    	}
    	elseif (is_string($mixed)) {
    		$mixed = addslashes($mixed);
    	}
    }
    
    addslashes_extended($data);
    
    print_r($data);

Array
(
    [0] => fo\'o
    [bar] => foo\'bar
    [foobar] => Array
        (
            [0] => 1
            [1] => 2
            [someObj] => stdClass Object
                (
                    [prop1] => a
                    [prop2] => b\'c
                )

        )

)