This part is quite confusing

@rnagpal what do you mean by >When I add logs statements I see temp-reaction being set as the ratom which the component uses

I think what you are seeing is the Reaction type being set in https://github.com/reagent-project/reagent/blob/5693716a7559a4f31bf2baf85378b3394a54e84e/src/reagent/ratom.cljs#L42

I believe the temp-reaction thing is a performance optimization to avoid creating reaction objects when there are no watchers. Specifically this optimization: https://github.com/reagent-project/reagent/blob/5693716a7559a4f31bf2baf85378b3394a54e84e/src/reagent/ratom.cljs#L505

The first line you pointed @lee.justin.m just sets the counter. But when I print temp-reaction in run-in-reaction function, I see different value of temp-reaction everytime

Which seems to be a reaction obj (sorry I previously mentioned ratom)

so keep in mind that Reaction has mutable fields

Hi, I’ve a quick question about adapt-react-class, etc. So,I’m using a react lib, did the clojure thing and wrote a couple functions to scan the source spit out a namespace with the require’s and a bunch def’s that just call adapt-react-class. This lib uses JSS so I have to set classes in my components. Does an adapted react class map :class from hiccup to :className? It doesn’t appear to, which is fine in general but in cases where it’s dynamic, I’m not getting to use the reagent :class [...] handling

the code is creating an empty reaction, and then it goes and mutates all those fields if needed

I didnt see where that mutation is happening. I did see the counter thing, but didnt see where other parts of this reaction are set

ok nvm lol. I was doing this late last night.. and was using :classes for some ungodly reason..

@rnagpal it happens in the when-not clause of run-in-reaction https://github.com/reagent-project/reagent/blob/5693716a7559a4f31bf2baf85378b3394a54e84e/src/reagent/ratom.cljs#L502-L511

See the (set! (.-f r) f) and related lines? Those lines mutate the temp-reaction

The reason for these shenanigans is a performance optimization. After deref-capture runs f, run-in-reaction checks to see if anything bothered to watch whether f actually derefed any atoms. If not, then it just returns the value of (f). if something did watch f did actually deref anything, only then does it actually cache the reaction on the key of obj

actually I think I have the “watcher” and the “watching” backwards. run-in-reaction ultimately stores a list of what is being watched on the cljsRatom property of each component (fixed)

Thanks @lee.justin.m will go though the code in some time and will try to make sense based on what you mentioned

Thanks for helping me

well those were good questions. i finally understand wtf is going on with reactions

I am adding some notes in the code, once it makes sense and I get the full picture, we can pick and add it to master

and actually, i think i realized the fundamental thing that has bugged me about reagent: because it performs watches at the ratom level, you effectively have to declare cursors everywhere. this is because there is no way to intercept get-in to get better watch lists. in in some way it defeats the purpose in the case where you store everything in a single atom