That EDN file starts with

{:clojure.main/message
 "Execution error (SocketException) at sun.nio.ch.NioSocketImpl/implWrite (NioSocketImpl.java:420).\nBroken pipe\n",
 :clojure.main/triage
 {:clojure.error/class java.net.SocketException,
  :clojure.error/line 420,
  :clojure.error/cause "Broken pipe",
  :clojure.error/symbol sun.nio.ch.NioSocketImpl/implWrite,
  :clojure.error/source "NioSocketImpl.java",
  :clojure.error/phase :execution},
 :clojure.main/trace
 {:via
  [{:type clojure.lang.ExceptionInfo,
    :message "Unexpected error during REPL initialization",
    :data {:cljs.repl/error :init-failed},
    :at [cljs.repl$repl_STAR_ invokeStatic "repl.cljc" 1220]}
   {:type java.net.SocketException,
    :message "Broken pipe",
    :at
    [sun.nio.ch.NioSocketImpl implWrite "NioSocketImpl.java" 420]}],
  :trace
  [[sun.nio.ch.NioSocketImpl implWrite "NioSocketImpl.java" 420]
   [sun.nio.ch.NioSocketImpl write "NioSocketImpl.java" 440]
   [sun.nio.ch.NioSocketImpl$2 write "NioSocketImpl.java" 826]
   [java.net.Socket$SocketOutputStream write "Socket.java" 1035]
   [jdk.internal.reflect.GeneratedMethodAccessor10 invoke nil -1]
   [jdk.internal.reflect.DelegatingMethodAccessorImpl
    invoke
    "DelegatingMethodAccessorImpl.java"
    43]
   [java.lang.reflect.Method invoke "Method.java" 568]
   [clojure.lang.Reflector invokeMatchingMethod "Reflector.java" 167]
   [clojure.lang.Reflector invokeInstanceMethod "Reflector.java" 102]
   [cljs.repl.server$send_and_close invokeStatic "server.clj" 168]

Maybe an idea to sidestep the problem could be to install chrome on the wsl2 itself? :thinking_face: https://docs.microsoft.com/en-us/windows/wsl/tutorials/gui-apps#install-google-chrome-for-linux

i've been doing dev on wsl2 for quite awhile now, i use shadow-cljs though and i'm able to connect to a repl just fine using any browser on windows side

i'll typically connect to a clj repl first then use cider-connect-sibling-cljs

"Start the REPL using the pattern described above, but with the browser as the evaluation environment.

(require '[cljs.repl :as repl])
(require '[cljs.repl.browser :as browser])  ;; require the browser implementation of IJavaScriptEnv
(def env (browser/repl-env)) ;; create a new environment
(repl/repl env) ;; start the REPL

Forgot to press "shift enter" again. I will complete what I was going to write shortly. The above is from https://clojurescript.org/reference/repl . It will fail at (repl/repl env) in WSL2 because of a socket not being released prior to an attempt to make a connection (I think). I am going to collect screenshots. I believe it is a Linux thing in general and not a WSL2 thing in particular, because https://clojurescript.org/guides/quick-start says: "If you are running Linux and the REPL does not start, try disabling browser auto-launch and opening `http://localhost:9000` manually:" The article does not say WHY some Linux setups won't work properly, but I believe it is the same issue.

The purpose of this next screenshot is to show the browser window opened, although I have just said that already. I hesitate highlight the ?rel=1640775390178 part, because it is undoubtedly not relevant, but does anyone know what it means?

"Fire up the Clojurescript Quick Browser REPL" in Calva and the same thing happens. The browser repl opens in a browser window, but it is inaccessible to the editor. Incidentally, I have until yesterday thought the browser REPL was a process or sub-process within the browser instance. It may still be, but something I read yesterday talked in terms of the browser being a separate process serving a/the browser REPL. Anyway, Calva presents us with the following screen. It says "Connecting cljs repl:", but it never does; it gets stuck here just like repl/repl got stuck in the clj repl above. I understand a cljs prompt is meant to appear after this, but I have never seen one on my system.

When I close the browser window, Calva prints out additional lines 22-27: A SocketException; Write failed because of a broken pipe. Calva then evaluates core.cljs (in package hello_world), but in nrepl, not the browser repl that we want.

I will refer to this screenshot next, as the Slack appears to always present the graphics at the end of each comment in the thread.

The above nREPL log does not record an error (though nrepl does reply with a repl type of clj when I would expect cljs), but cider.piggieback/cljs-repl returns the following error when repeated in the editor (because, I presume the http server is holding onto a broken pipe making its socket unavailable):     Execution error (BindException) at http://java.net.PlainSocketImpl/socketBind (PlainSocketImpl.java:-2).     Address already in use (Bind failed)

That's me for the moment. Good luck.

You can try using shadow-cljs. You can then require most of the npm libraries you have installed in your project doing something like (:require ["react" :as react])

Thanks Arthur. Does that have a downside on the performance?

What is the baseline against which you want to compare using shadow-cljs?

According to a cljs REPL, map? is satisfies? IMap, set? is ISet, and sequential? is ISequential. (based on calling source on each of these)

(so you'll need to extend those protocols to whatever your new thing is)

It's for a walking protocol, so I won't need to extend them, but every type which implements them 😞

I suspected as much. Sorry.

Can you extend protocols to protocols on cljs or is it the same problem as in clj?

No idea. My knowledge of cljs and its differences from clj is minimal.

ahaha @UK0810AQ2 looks like we're on the exact same page this morning https://clojurians.slack.com/archives/C07UQ678E/p1640797627283600

Lol, seems like Ethan's solution is the way to go then.

to answer my own question, <p! needs to be in :require not :require-macros