function createJsonTree($array, $currentParent, $currLevel = 0, $prevLevel = -1) {
foreach ($array as $categoryId => $category) {
if ($currentParent == $category['parent']) {
if ($currLevel > $prevLevel) $output .= ' , "children":[ ';
if ($currLevel == $prevLevel) $output .= " }, ";
$output .= '{ "data" :'.'"'.$category['menu_title'].'"';
if ($currLevel > $prevLevel) { $prevLevel = $currLevel; }
$currLevel++;
$output .= self::createJsonTree($array, $category['id'], $currLevel, $prevLevel);
$currLevel--;
}
}
if ($currLevel == $prevLevel) $output .= " }] ";
return $output;
}