diff --git a/src/core/index.js b/src/core/index.js
index 109c70f9..1007d87c 100644
--- a/src/core/index.js
+++ b/src/core/index.js
@@ -177,15 +177,15 @@ export default function SwaggerUI(opts) {
 
   const configUrl = queryConfig.config || constructorConfig.configUrl
 
-  if (!configUrl || !system.specActions || !system.specActions.getConfigByUrl || system.specActions.getConfigByUrl && !system.specActions.getConfigByUrl({
-    url: configUrl,
-    loadRemoteConfig: true,
-    requestInterceptor: constructorConfig.requestInterceptor,
-    responseInterceptor: constructorConfig.responseInterceptor,
-  }, downloadSpec)) {
-    return downloadSpec()
+  if (configUrl && system.specActions && system.specActions.getConfigByUrl) {
+    system.specActions.getConfigByUrl({
+      url: configUrl,
+      loadRemoteConfig: true,
+      requestInterceptor: constructorConfig.requestInterceptor,
+      responseInterceptor: constructorConfig.responseInterceptor,
+    }, downloadSpec)
   } else {
-    system.specActions.getConfigByUrl(configUrl, downloadSpec)
+    return downloadSpec()
   }
 
   return system