allow nil app node id

README.md

@@ -25,7 +25,7 @@ browser you can use `cljs-test-display`.
 
 <img src="https://s3.amazonaws.com/bhauman-blog-images/cljs-test-display-tab.png" width="500"/>
 
-* Numbered stacktraces for exceptions in the dev console
+* Numbered stacktraces for test exceptions in the dev console
 
 <img src="https://s3.amazonaws.com/bhauman-blog-images/cljs-test-display-error-stacktrace.png" width="500"/>
 
@@ -40,6 +40,7 @@ browser you can use `cljs-test-display`.
 * Straightforward integration
 
 ```clojure
+;; where "app" is the HTML node where you want to mount the tests
 (cljs.test/run-tests 
   (cljs-test.display.core/init! "app") ;;<-- initialize cljs-test-display here
   'example.foo-test 

src/cljs_test_display/core.cljs

@@ -400,17 +400,17 @@
                        'example.core-other-test)"
   ([] (init! nil))
   ([app-node-id]
-   (assert (or (string? app-node-id)
-               (symbol? app-node-id)
-               (keyword? app-node-id))
-           "Must provide an something we can call cljs.core/name on.")
-   (assert (gdom/getElement (name app-node-id))
+   (when app-node-id
+     (assert (or (string? app-node-id)
+                 (symbol? app-node-id)
+                 (keyword? app-node-id))
+             "Must provide an something we can call cljs.core/name on.")
+     (set! root-node-id (name app-node-id)))
+   (assert (gdom/getElement (name root-node-id))
            (str "cljs-test-display: Element with id "
                 (pr-str root-node-id)
                 " does not exist."))
    (when notifications (notify/ask-permission!))
-   (when app-node-id
-     (set! root-node-id (name app-node-id)))
    (insert-style!)
    (register-document-events!)
    (set! (.-innerHTML (root-app-node)) "")