Clojurians Log v2

Thanks @andre I have updated re-frame-template to use the latest re-frisk release.

reg-* should really be macros that def vars don't @ me 😉

is this > (def event:event-name ::event-name) some kind of namespacing by convention, i.e. the use of : in the symbol there? @emccue

I feel that this is probably a FAQ, but I haven’t been able to scare up an answer. Is there some way to “weakly subscribe” to something in the database? I.e. I want access to the value within my component, but I don’t want my component to update when the value changes. Is this possible?

Using a form-2 Reagent component should help.

Or reagent.core/with-let with @ being inside its bindings form.

I think I see what you’re suggesting. If I understand, that will allow me to access the value as it was when the component was created. I’m interested in whatever the value happens to be right now. Let me try to explain: I have :x, :y, and :z in the app-db. I want my component to update whenever :x or :y change, but when it updates, take whatever the current value of :z is into account. If I subscribe to :z, it will also update whenever :z changes. Perhaps I can do that with a form-2 component, but I’m not sure I can immediately see how?

I see. Well, a proper re-frame friendly approach would be to have an extra key, something like :z-for-x-y, that would be set to the value of :z only when :x or :y is changed. And you would just subscribe to the value of :z-for-x-y - no magic whatsoever. If you don't have a small known set of events that update :x and :y where you could put the code updating :z-for-x-y, you can use a global interceptor for it.

Ah, got you. Thanks. Perhaps I should explain what I’m trying to do in more detail - there may be a completely different way to solve the problem: I’m writing a component which wraps a large pre-existing Javascript component (https://vega.github.io/vega/). I’m doing this by having a component like this:

(defn vega-view []
  (let [data @(re-frame/subscribe [:vega-data])]
    [:div {:ref #(create-view % data)}]))

Just use https://github.com/vega/react-vega. ;) It deals with all that.

And use it via regular Reagent/React interop - works like a charm for me.

yeah

Ah! Good luck to find someone else doing something very similar! I did try to use react-vega back when I started down this road, and got into a real mess. Perhaps I should revisit. I’m not sure that it could solve the problem that I’m trying to solve though? I’m programmatically generating my Vega spec (because the spec changes depending on the specifics of the data being visualised) and want to save the values of certain signals from the previous instance of Vega and copy them into the new one.

I also generate the spec depending on the data. But I've never tried preserving signal values.

might macro it up at some point if the pattern holds, but for now biting the bullet of typing so we don't get hard locked in

No worries. I think you’ve answered my main question which is that my initial thought about how to use re-frame won’t fly (for which many thanks). I can certainly find a way to make it work, it’ll just be a bit messy (which is fine - the interface between a nice functional re-frame app and a very imperative Vega component will always get a bit messy at the join…)

I’m curious now - what are you visualising?

so for @p-himik's example we would do this

;; Events
(def event:user-typed ::user-typed)

(defn user-typed [text]
  [event:user-typed text])

(defn handler:user-typed
  [{:keys [db]} [_ text]]
  {:db (update db ::model/page-state
                  :user-input assoc text)
   :fx []})

(rf/reg-event-fx event:user-typed handler:user-typed)

;; view
(defn input [{:keys [user-input]}]
  [:input {:value user-input
           :on-change #(rf/dispatch (events/user-typed %))}])

I'm working together with the Utrecht University on a platform that would allow users to select the right breeding partners for their dogs, so all the breeding regulations are followed - to avoid any diseased offspring. The platform itself is not public yet, but here are a couple of charts from the work in progress: file:///home/p-himik/Pictures/screenshots/Screenshot_20210420_175902.png

Where would you use user-typed without dispatch?

Very nice! 👍

in the tests like bove

Ah, I see now, thanks.

You can also check this out. I’ve been using this strategy to wrap OpenLayers, which is highly stateful and imperative. https://github.com/day8/re-frame/blob/master/docs/Using-Stateful-JS-Components.md

Warning: it’s not fun but it works. 🙂

So I am pitching in on a re-frame project and cannot figure out what version of re-frame is being used. The shadow-cljs.edn pulls in only [day8.re-frame/re-frame-10x "0.6.0"]. I cannot find any other "re-frame" linkage. They also use NPM, but npm list shows only react stuff. Damn I miss project.clj. 🙂 Anyone have any idea how to find out what version they are using. Their timezone is unconscious right now or I would ask them. Thx! 🙏

Ah, found a re-frame-1.1.2 jar under shadow-cljs. Bingo.