Join all connections at the given identity (or just one if endpointId provided) to channel contextGroupId. If no target is specified, it adds the sender to the channel.

This is a wrapper for interop.joinContextGroup.

Example

joinViewToChannel = async (contextGroupId, view) => {
    await fdc3.joinContextGroup(contextGroupId, view);
}

getLastFocusedView()
    .then(lastFocusedViewIdentity => {
        joinViewToChannel('red', lastFocusedViewIdentity)
    })