To use a Connection in JavaScript, it must be a part of the Flow.
If the Connection is a part of the source-to-destination transformation, it is automatically added to the list and can be referenced anywhere within the JavaScript in the original source-to-destination Flow, in the nested Flow, which includes the source-to-destination Flow, and in all inner-Flows.
If the Connection is not a part of the source-to-destination transformation, it must be added manually to the nested Flow.