Grokking Fulcro part 2 is now available: https://youtu.be/102nHLzIbE4

Thank you all who contributed to the Fulcro Rationale! I will now add it to the minimalist tutorial and also share it with the community.

On the topic inputs, I'd like to revisit a question I asked previously, but didn't quite get straight in my head. Let's say I have a number of inputs, and a save button (or something else that needs to know some sum total of the inputs). Let's say I want the save button to disable and enable interactively as the user types valid or invalid values into the inputs. I only want the save button and the currently selected input to refresh. I don't want to re-render all components in the parent when the currently selected input is manipulated. It seems to me that in order to get this to work, I'd have to put the save button in a component with some ident that can be targeted independently, and give it props to know whether the inputs are valid or not. After that, I seem to have two options: 1. Use transact! and give :only-refresh the idents of the input and the save button component. 2. Use transact!! and immediately schedule a refresh of the save button component afterwards, by putting a comp/refresh-component! as the second arg to a do block. Which of these is preferable? Is there some other option that I haven't considered (barring "don't refresh the state of the save button interactively" of course, which would invalidate the entire question)

I isolated a quirky situation with a union query and placeholder logic :>/bla where the final merged result is not what I would expect. The :cmmn.case/state prop is missing, as demonstrated in the test at the bottom. I'm not sure whether this is a bug or expected behaviour?

(defn get-case-ident
  [props]
  (let [case-id? string?]
    (cond
      (-> props :nexus.case.image-annotation/id merge/nilify-not-found case-id?) [:nexus.case.image-annotation/id (:nexus.case.image-annotation/id props)]
      (-> props :nexus.case.test-case/id merge/nilify-not-found case-id?) [:nexus.case.test-case/id (:nexus.case.test-case/id props)]
      :else (log/error "Cannot derive a valid ident. Invalid props." props))))

(defsc AddState [_ _]
  {:query [:nexus.case.image-annotation/id
           :cmmn.case/state]
   :ident :nexus.case.image-annotation/id})

(defsc ImageAnnotationCase [this props]
  {:query [:nexus.case.image-annotation/id
           :cmmn.case/name
           ;; cmmn.case/state -> not queried here but under :>/bla placeholder!
           {:>/bla (comp/get-query AddState)}]
   :ident :nexus.case.image-annotation/id})

(defsc TestCase [this props]
  {:query [:nexus.case.test-case/id
           :cmmn.case/name
           :cmmn.case/state]
   :ident :nexus.case.test-case/id})

(defsc CaseUnion
  "Union query component for different Case types."
  [this props computed]
  {:query (fn [] {:nexus.case.test-case/id        (comp/get-query TestCase)
                  :nexus.case.image-annotation/id (comp/get-query ImageAnnotationCase)})
   :ident (fn [] (get-case-ident props))})


(deftest bla
  (behavior "Reproduce situation where the :cmmn.case/state of the first case doesn't show up in merged props"
    (let [response [{:nexus.case.image-annotation/id "case-id-00000001"
                     :cmmn.case/name                 "Annotate Image 1"
                     :cmmn.case/state                ::merge/not-found ;; Note: I captured this by logging data-tree in pre-merge
                     :>/bla                          {:nexus.case.image-annotation/id "case-id-00000001"
                                                      :cmmn.case/state                "completed"}}
                    {:nexus.case.test-case/id "case-id-00000004"
                     :cmmn.case/name          "Test Case 1",
                     :cmmn.case/state         "active"}]]

      (assertions
        "Show that :cmmn.case/state isn't merged"
        (merge/merge-component {} CaseUnion response) =>
        {:nexus.case.image-annotation/id {"case-id-00000001" {:nexus.case.image-annotation/id "case-id-00000001"
                                                              :cmmn.case/name                 "Annotate Image 1"
                                                              ;; :cmmn.case/state             "completed" <== EXPECTED!!
                                                              :>/bla                          [:nexus.case.image-annotation/id "case-id-00000001"]}}
         :nexus.case.test-case/id        {"case-id-00000004" {:nexus.case.test-case/id "case-id-00000004"
                                                              :cmmn.case/name          "Test Case 1"
                                                              :cmmn.case/state         "active"}}}

        ))))

since there's not a guardrails channel, I'll ask here: is there a way of creating a normal value with a spec (like def)? It seems that >def is used to create specs, non specced values

also, when I trigger a spec error, is there a way of getting back a stack trace of the functions that triggered it?

Has anyone tried to connect Fulcro with Firestore (from the client side, no server)? That's the setup I'm working with and considering using Fulcro. It feels like Firestore could be treated as a remote, and any real time updates simply fed to the app as load!s. Is there any prior art here?

I'm a bit worried about spamming Firestore with reads that aren't necessary. But perhaps if I write it properly the queries never hit Firestore, and instead I just request all the working data up front, and let Firestore subscriptions keep the client DB up to date. That's not going to be practical in every app, but it is for my two use cases.