handle missing ROS for VideoStream

src/VideoStream/index.js

@@ -13,12 +13,14 @@ class VideoStream extends Component {
             url: hasUrl ? this.props.url : this.defaultImage
         };
 
+        if (this.props.ros) {
             this.props.ros.getTopics(function(infos){
                 if (undefined !== infos.topics.find(elem => elem === this.topic)) {
                     this.setState({url: 'http://localhost:8081/stream?topic=' + this.topic});
                 }
             }.bind(this))
         }
+    }
 
     handleSettingsChange(event) {
         this.setState({url: event.target.value})