Consider if this is the best approach. Why can’t you just have the one rule with both triggers? When the rule is triggered based on cron the event Object will be undefined. So if all you are doing here is trying to tell the difference between the two triggers, it’s not necessary.
if(event === undefined) {
// cron or manually triggered
}
else {
// Item or Channel event triggered
}
It is almost always better to use a module rather than calling another rule to share code between rules. Not only can you pass arguments but you can get a return value as well. Modules are easier to share with other users and among your other rules also. I talk a little bit about creating modules at Some JS Scripting UI Rules Examples, though you can probably just put the .js file in a folder under node_modules.
There are some use cases where having a rule call a rule is a good choice but I’m not certain this is one of them. But for completeness, assuming that the called rule is also ECMAScript 2021 there will just be a trigger_type variable available in the called rule.