Without hooks

package.json

@@ -1,11 +1,11 @@
 {
   "name": "uix-starter",
   "scripts": {
-    "dev": "shadow-cljs -A:dev watch app & yarn styles-dev",
-    "release": "shadow-cljs -A:dev release app && yarn styles-release",
+    "dev": "shadow-cljs -A:dev run dev.build/start & yarn styles-dev",
+    "release": "shadow-cljs -A:dev run dev.build/release && yarn styles-release",
     "styles-dev": "onchange -o '> public/main.css && lightningcss --bundle public/main.css -o public/main.css' -i src/**/*.css -- cat src/**/*.css",
     "styles-release": "cat src/**/*.css > public/main.css && lightningcss --minify --bundle public/main.css -o public/main.css",
-    "start:libs": "mkdir -p target/gen && touch target/gen/libs.js && node watch.mjs",
+    "start:libs": "node watch.mjs",
     "build:libs": "node build.mjs"
   },
   "dependencies": {

shadow-cljs.edn

@@ -8,15 +8,10 @@
            :js-options {:js-provider :external
                         :external-index "target/gen/libs.js"
                         :external-index-format :esm}
-           :release {:build-hooks [;; Esbuild must run after shadow-cljs flush so no way to optimize.
-                                   ;; You can replace yarn with npm.
-                                   (dev.build/run-cmd-flush {:cmd ["yarn" "build:libs"]
-                                                             :once true})]
-                     ;; If you want to enable module-hash-names you need to fix the references in the index.html to refer to
+           :release {;; If you want to enable module-hash-names you need to fix the references in the index.html to refer to
                      ;; the new names.
                      ;; ESBuild can also enable this.
                      ;; Shadow-cljs would write information about created output files in public/js/manifest.edn and ESBuild in
                      ;; public/js/manifest.json (if you enable that in build.mjs)
                      ;; :module-hash-names true
-                     }
-           :dev {:build-hooks [(dev.build/run-cmd-configure {:cmd ["yarn" "start:libs"]})]}}}}
+                     }}}}

src/dev/build.clj

@@ -1,4 +1,5 @@
-(ns dev.build)
+(ns dev.build
+  (:require [shadow.cljs.devtools.api :as shadow]))
 
 (defn start-process [cmd]
   (let [;; Redirect output to stdout.
@@ -11,6 +12,27 @@
     (.addShutdownHook (Runtime/getRuntime) (Thread. (fn [] (.destroy process))))
     process))
 
+;; New version - main function
+
+(defn start
+  {:shadow/requires-server true}
+  [& _args]
+  ;; Watch call blocks until the first build is done -> the index file
+  ;; will be available when ESBuild is started
+  (shadow/watch :app)
+  (start-process ["yarn" "start:libs"])
+  ::started)
+
+(defn release
+  []
+  (shadow/release :app)
+  (.waitFor (start-process ["yarn" "build:libs"])))
+
+;; Old version - hooks
+
+;; TODO: Hooks might run multiple times, for example if the shadow-cljs.edn is changed
+;; -> multiple ESBuild processes
+;; Consider "main ns" to run the process & Shadow-cljs, so no need for hooks?
 (defn run-cmd-configure
   {:shadow.build/stage :configure}
   [build-state {:keys [cmd]}]