MariaDB Connector/node.JS only appears to have very limited timezone support at the moment:

timezone
Forces use of the indicated timezone, rather than the current Node.js timezone. Possible values are Z for UTC, local or ±HH:MM format

https://mariadb.com/kb/en/library/nodejs-connection-options/#other-options

https://github.com/MariaDB/mariadb-connector-nodejs/blob/0b2a9296f3b555baefe1fc631ae4fbb772bff8b5/lib/config/connection-options.js#L78

The connector should also support named time zones, just as the server does. Otherwise, the connector can't handle daylight savings time.

https://mariadb.com/kb/en/library/time-zones/#setting-the-time-zone

It looks like time zones might currently be implemented this way because the connector tries to do a simplistic form of time zone conversions on its own:

https://github.com/MariaDB/mariadb-connector-nodejs/blob/0b2a9296f3b555baefe1fc631ae4fbb772bff8b5/lib/cmd/common-text-cmd.js#L388

But why doesn't the connector just do SET SESSION time_zone = "..." and let the server handle the time zone conversions?