Two ways to solve it: 1. If it's used only in one place: @(subscribe [@(subscribe [:something id]) id]) 2, If it's used in multiple places, reg-sub-raw that uses other subs sounds like what you need.

(re-frame/reg-sub :my-sub
  (fn [[_ id _] _]
    (re-frame/subscribe [:another-subscription id]))
  (fn [result-of-another-subscription _]
    (do-something-with result-of-another-subscription)))

That's not the same thing as replacing a sub ID though, as the OP wants.

Oh, in that case I misunderstood the question.

Sorry both, I think I might have explained badly. Looking back "id" was a poor choice of parameter. I think @U4ZDX466T has the use case I'm looking for, but the nested subscribes by @U2FRKM4TW very cool. So thank you both! 🙂

For the suggestion from @U4ZDX466T, a good beginner trick is to first skip all the destructuring and just print values coming through, so you properly understand what’s going on. Common stumbling point:

(f/reg-sub :my-derived-sub
  (fn [arg1 arg2]
    (println arg1 arg2)
    (f/subscribe [::my-sub (second arg1)]))
  (fn [sub-value arg2]
    (println arg2)
    (do-something sub-value)))

I see people struggling a lot with these things, both in events and subs (myself included) 🙂

Yeah, that's good point. I always forget the order in which the arguments arrive myself, too. 🙂

Also, don't use the 2-arity version of the signal function: https://github.com/day8/re-frame/wiki/Dynamic-Subscriptions

Perhaps you need to read this: https://github.com/day8/re-frame/blob/master/docs/FAQs/Why-Clear-Sub-Cache.md

Thank you so much! Should have checked the FAQs, sorry. This is exactly what I needed 🙂