I have been using Clojure, ClojureScript, lein, shadow-cljs, Emacs, and CIDER to work on a Clojure/ClojureScript dynamic web app project.
Usually, I build the project executing command cider-jack-in-cljs in Emacs, choosing shadow-cljs, then shadow for REPL type, and, finally, app for building option.
It works fine. I can watch changes on the UI on localhost:3005.
There is something weird though that I do not understand (take into consideration that I am new to the Clojure stack).
On the REPL I can do:
cljs.user> @(re-frame.core/subscribe [:the-selections])
{:firm "cb08795f-378b-4eb0-9404-ad83b83a8474",
:active-client "Random-client",
:active-atb "c6193c35-bf91-4711-8523-d905bd7f0a03"}
The keywords inserted by me and retrieved by the REPL are related to the project.
My doubt is about the fact that this only works if the browser is in a specific page (address). Authentication here is not relevant.
On http://localhost:3005/link/random-numbers-asidadbsadkfbajhksdbf9283492374, it works:
cljs.user> @(re-frame.core/subscribe [:the-selections])
{:firm "cb08795f-378b-4eb0-9404-ad83b83a8474",
:active-client "Random-client",
:active-atb "c6193c35-bf91-4711-8523-d905bd7f0a03"}
But, if change the address bar on the Chrome browser to another valid path being properly rendered by the browser: http://localhost:3005/another-path.
And if try the same command, surprisingly the REPL retrieves nil:
cljs.user> @(re-frame.core/subscribe [:the-selections])
nil
Even after authentication and even if the browser address is inside the home page, the command above does not work. It only works after the address is on a specific page.
In addition, based on @ThomasHeller's comment, it seems to be relevant to post how :the-selections is defined. I am not sure this is the root of the definition, but it is my best bet:
(rf/reg-sub
:the-selections
;; Only returns something if all :firm, :active-client, and
;; :active-atb are present. :raw-selections defined in
;; selections.cljs omits validation if (rarely) needed. selections
;; are only stored locally in re-frame's app-db, not in firebase,
;; like :the-client and :the-atb. Minor selections components which
;; are not part of the validation are :active-account and :active-je
(fn [_q _d]
(rf/subscribe [:raw-selections]))
(fn [selections _q]
(tc-selections/valid-selections selections)))
This behavior intrigues me. Isn't a re-frame.core/subscribe an interface to the database?
According to re-frame's documentation:
When a View Function uses a subscription, like this (subscribe [:something :needed]), the sub-graph of nodes needed to service that subscription is created. The necessary sub-graph will "grow backwards" from the View Function all the way to app-db.
If so, why should the address bar on the browser matter after proper build and authentication?
This is impossible to answer without knowing how :the-selections is defined.
However, a guess would be that the value is provided by the "router". It basically takes the URL and puts some data related to it into the app-db. In case of URIs starting with /link it may be creating the necessary data, while others don't.