diff --git a/src/main/clojure/cljs/build/api.clj b/src/main/clojure/cljs/build/api.clj
index d8cbd99667..efb0de14bd 100644
--- a/src/main/clojure/cljs/build/api.clj
+++ b/src/main/clojure/cljs/build/api.clj
@@ -204,8 +204,8 @@
        (env/default-compiler-env opts))))
   ([source opts compiler-env]
    (doseq [[unknown-opt suggested-opt] (util/unknown-opts (set (keys opts)) closure/known-opts)]
-     (println (str "WARNING: Unknown compiler option '" unknown-opt "'."
-                (when suggested-opt (str " Did you mean '" suggested-opt "'?")))))
+     (when suggested-opt
+       (println (str "WARNING: Unknown compiler option '" unknown-opt "'. Did you mean '" suggested-opt "'?"))))
    (binding [ana/*cljs-warning-handlers* (:warning-handlers opts ana/*cljs-warning-handlers*)]
      (closure/build source opts compiler-env))))
 
diff --git a/src/main/clojure/cljs/repl.cljc b/src/main/clojure/cljs/repl.cljc
index ee8dca22f1..ecffd9abfe 100644
--- a/src/main/clojure/cljs/repl.cljc
+++ b/src/main/clojure/cljs/repl.cljc
@@ -780,8 +780,8 @@
                   bind-err true}
              :as opts}]
   (doseq [[unknown-opt suggested-opt] (util/unknown-opts (set (keys opts)) (set/union known-repl-opts cljsc/known-opts))]
-    (println (str  "WARNING: Unknown option '" unknown-opt "'."
-               (when suggested-opt (str " Did you mean '" suggested-opt "'?")))))
+    (when suggested-opt
+      (println (str "WARNING: Unknown option '" unknown-opt "'. Did you mean '" suggested-opt "'?"))))
   (let [repl-opts (-repl-options repl-env)
         repl-requires (into repl-requires (:repl-requires repl-opts))
         {:keys [analyze-path repl-verbose warn-on-undeclared special-fns static-fns] :as opts