public static function keyExists($key, $array, $caseSensitive = true)
{
if ($caseSensitive) {
// Function `isset` checks key faster but skips `null`, `array_key_exists` handles this case
// http://php.net/manual/en/function.array-key-exists.php#107786
return isset($array[$key]) || array_key_exists($key, $array);
} else {
foreach (array_keys($array) as $k) {
if (strcasecmp($key, $k) === 0) {
return true;
}
}
return false;
}
}