Changed loop that goes over settings so it doesn't delete default service_worker_url if one isn't passed

Author: TalAter

dist/upup.min.js

@@ -45,10 +45,9 @@ same settings object directly to the start() method.
     UpUp.start({ content: 'Cannot reach site. Please check your internet connection.' });
 
 The settings object supports the following options:
-- `content-url`         (String) The content to display when user is offline (url to the content that will be served)
-- `content`             (String) The content to display when user is offline (plain text, HTML, etc.)
-- `assets`              (Array)  Array of assets to cache for offline access
-- `service-worker-url`  (String) The `upup.sw.js`'s url, allows placing `upup.js` and `upup.sw.js` in different directories and using CDNs.
+- `content-url`  (String) The content to display when user is offline (url to the content that will be served)
+- `content`      (String) The content to display when user is offline (plain text, HTML, etc.)
+- `assets`       (Array)  Array of assets to cache for offline access
 
 # API Reference
 
@@ -102,3 +101,4 @@ debug state on or off.
 * **Boolean** *[newState=true]* - Turn on/off debug messages
 
 <!-- End src/upup.js -->
+

dist/upup.min.js.map

@@ -150,7 +150,9 @@
 
       // add new settings to our settings object
       ['content', 'content-url', 'assets', 'service-worker-url'].forEach(function(settingName) {
-        _settings[settingName] = settings[settingName] || null;
+        if (settings[settingName] !== undefined) {
+          _settings[settingName] = settings[settingName];
+        }
       });
     },