Returns true if given key is set in the cookie.

@param string|null $key Key to check for
@return bool True if the key exists
358979
public function check($key = null)
    {
        if (empty($key)) {
            return false;
        }

        return $this->read($key) !== null;
    }
927735
public function has($key) {
        if (isset($this->store[$key])) {
            if ($this->ttl == 0) {
                return true;
            } else if ($this->store[$key][1] >= (cache::now() - $this->ttl)) {
                return true;
            }
        }
        return false;
    }
52721
public function cookie($key = null, $default = null)
    {
        $cookies = $this->getCookieParams();

        return is_null($key) ? $cookies : data_get($cookies, $key, $default);
    }
1229019
public static function has(string $key):bool
    {
        return self::getViewHelper()->getView()->getValue($key) !== null;
    }
723954
public function has($key)
	{
		$key = $this->id($key);

		if (!isset($this->data[$key]))
		{
			return false;
		}

		$value = $this->data[$key];

		if ($this->isDataExpired($value))
		{
			unset($this->data[$key]);
			return false;
		}

		return true;
	}
1237118
private function has($key) {
		return isset($_SESSION[self::SESSION_KEY_FLASH]) && isset($_SESSION[self::SESSION_KEY_FLASH][$key]);
	}
467384
public function has($key)
    {
        $value = $this->get($key);

        return ! is_null($value) && $value !== false;
    }
591173
public function has($key)
    {
        if ($this->where == true) {
            $this->setCache($key)->setPath(CYGNITE_BASE.DS.toPath('public.storage.cache').DS);
        }

        $cached = $this->getCache();

        return !empty($cached[$key]) ? true : false;
    }
1065108
public function hasHeader(string $key = null) : bool
	{
		if ($key === null) {
			return false;
		}

		$array = $this->getHeaders();
		return isset($array[$key]) || array_key_exists($key, $array);
	}
42777
public function remove($key)
    {
        if ($this->has($key)) {
            // Set cookie in the past
            $this->set($key, '', -86400);
            // And also make sure it won't be available on the current HTTP request
            unset($this->cookies[$key]);
            return true;
        } else {
            return false;
        }
    }
1212782
public function __isset($key) {
        switch (true) {
            case isset($this->_params[$key]):
                return true;
            case isset($this->GET[$key]):
                return true;
            case isset($this->POST[$key]):
                return true;
            case isset($_COOKIE[$key]):
                return true;
            case isset($this->SERVER[$key]):
                return true;
            case isset($this->ENV[$key]):
                return true;
            default:
                return false;
        }
    }
551349
public function has(?string $key) : bool
    {
        return $key === null ? false : isset($this->themes[$key]);
    }
170730
public static function has( $key )
	{
		$cache = self::instance();
		if ( $cache ) {
			return $cache->isExisting( $key );
		}
		return false;
	}
1130787
public function has($key)
    {
        $key = $this->getKeyCode($key);

        $value = $this->memcacheObj->get($key);
        
        if (!$value) {
            return false;
        } else {
            return true;
        }
    }
266238
public function exists(?string $key = null) : bool
    {
        $key = $this->constructKey($key);

        return $this->parseKey($key, function ($part, $result) {
            return array_key_exists($part, $result);
        });
    }
125802
public function removeCookieItem($key)
    {
        if (isset($this->cookie[$key])) {
            unset($this->cookie[$key]);
            return true;
        } else {
            return false;
        }
    }
36116
public function cookies($key = null)
    {
        if ($key) {
            return $this->cookies->get($key);
        }

        return $this->cookies;
       
    }