MariaDB Connector/node.JS only appears to have very limited timezone support at the moment:
Forces use of the indicated timezone, rather than the current Node.js timezone. Possible values are Z for UTC, local or ±HH:MM format
The connector should also support named time zones, just as the server does. Otherwise, the connector can't handle daylight savings time.
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:
But why doesn't the connector just do SET SESSION time_zone = "..." and let the server handle the time zone conversions?