Add a one-terminal REPL script

package.json

@@ -28,7 +28,7 @@
   },
   "scripts": {
     "print-version": "echo $npm_package_version",
-    "repl": "yarn shadow-cljs watch lib",
+    "repl": "./scripts/repl",
     "watch": "yarn shadow-cljs watch lib",
     "build": "yarn shadow-cljs release lib",
     "test": "yarn shadow-cljs release test && node dist/test.js",

scripts/repl

@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+#
+# Call yarn shadow-cljs watch and then launch node fonda.js.
+#
+# Note: the $@ parameters are forwarded to yarn shadow-cljs not to the node
+# command.
+#
+set -euo pipefail
+
+output_dir=dist
+output_file=$output_dir/fonda.js
+
+shadow_dir=.shadow-cljs
+shadow_pid_file=$shadow_dir/server.pid
+
+shadow_build="lib"
+shadow_bin="yarn shadow-cljs"
+shadow_subcmd="watch"
+
+node_bin=$(which node)
+node_opts="--inspect $output_file"
+
+function cleanup {
+  pkill $(cat "$shadow_pid_file");
+}
+
+set +e
+rm -v "$output_file"
+set -e
+
+shadow_cmd="$shadow_bin $shadow_subcmd $shadow_build $@"
+echo "Executing \"$shadow_cmd\"..."
+$shadow_cmd &
+
+# active loop waiting for the js file to appear
+i=1
+spinner="/-\|"
+echo -n ' '
+while [ ! -f "$output_file" ]; do
+    for c in / - \\ \|; do
+        printf '\b%s' "$c";
+        sleep .1
+    done
+done
+
+node_cmd="$node_bin $node_opts"
+echo "The shadow-cljs REPL is up."
+echo "Executing \"$node_cmd\"..."
+
+$node_cmd
+
+trap "set +e; do_cleanup" ERR SIGTERM SIGINT EXIT