make fast-initial-prompt? accessible to 3rd party REPLs. also make it possible

to show it after -setup by supporting :after-setup as a value. Only show the
prompt as soon as possible if the value is explicitly true.

Author: swannodette

src/main/clojure/cljs/cli.clj

@@ -298,8 +298,9 @@ is trying load some arbitrary ns."
       (subs repl-ns (count "cljs.repl.")))))
 
 (defn- fast-initial-prompt? [repl-env inits]
-  (and (empty? inits)
-       (contains? #{"node"} (repl-name repl-env))))
+  (boolean
+    (and (empty? inits)
+         (contains? #{"node"} (repl-name repl-env)))))
 
 (defn- repl-opt
   "Start a repl with args and inits. Print greeting if no eval options were
@@ -316,7 +317,10 @@ present"
         renv   (apply repl-env (mapcat identity reopts))]
     (repl/repl* renv
       (assoc (dissoc-entry-point-opts opts)
-        ::repl/fast-initial-prompt? (fast-initial-prompt? repl-env inits)
+        ::repl/fast-initial-prompt?
+        (or (fast-initial-prompt? repl-env inits)
+            (::repl/fast-initial-prompt? (repl/repl-options renv)))
+
         :inits
         (into
           [{:type :init-forms

src/main/clojure/cljs/repl.cljc

@@ -1059,7 +1059,7 @@
   (doseq [[unknown-opt suggested-opt] (util/unknown-opts (set (keys opts)) (set/union known-repl-opts cljsc/known-opts))]
     (when suggested-opt
       (println (str "WARNING: Unknown option '" unknown-opt "'. Did you mean '" suggested-opt "'?"))))
-  (when fast-initial-prompt?
+  (when (true? fast-initial-prompt?)
     (initial-prompt quit-prompt prompt))
   (let [repl-opts (-repl-options repl-env)
         repl-requires (into repl-requires (:repl-requires repl-opts))
@@ -1125,6 +1125,8 @@
                         (if-let [merge-opts (:merge-opts (-setup repl-env opts))]
                           (merge opts merge-opts)
                           opts)))
+               _    (when (= :after-setup fast-initial-prompt?)
+                      (initial-prompt quit-prompt prompt))
                init (do
                       (evaluate-form repl-env env "<cljs repl>"
                         `(~'set! ~'cljs.core/*print-namespace-maps* true)