src/DotKey.php
public function exists($key)
    {
        $index = explode('.', $key);
        self::getValue($this->item, $index, false, $err);
        
        return !$err;
    }
public function exists($key)
    {
        $index = explode('.', $key);
        self::getValue($this->item, $index, false, $err);
        
        return !$err;
    }
Check if property exists

@param string $key The index to fetch in dot notation
@return boolean