Bot check if dialog already active
// https://github.com/Microsoft/BotBuilder/blob/master/Node/examples/basics-help/apps.js
function switchTasks(session, args, next, alreadyActiveMessage) {
// Check to see if we're already active.
// - We're assuming that we're being called from a triggerAction() some
// args.action is the fully qualified dialog ID.
var stack = session.dialogStack();
if (builder.Session.findDialogStackEntry(stack, args.action) >= 0) {
session.send(alreadyActiveMessage);
} else {
// Clear stack and switch tasks
session.clearDialogStack();
next();
}
}