fix some eslint errors

Author: stsdc

.eslintrc.json

@@ -53,7 +53,8 @@
         "no-else-return": "off",
         "jsx-a11y/no-noninteractive-element-interactions": "warn",
         "jsx-a11y/media-has-caption": "off",
-        "object-curly-newline": "off"
+        "object-curly-newline": "off",
+        "no-unused-expressions": [ "error", {"allowTernary": true}]
     }
 
 }

client/src/js/view/components/topbar.js

@@ -74,8 +74,14 @@ const toggleFullscreen = (event) => {
 
     const isFullscreen = document.webkitIsFullScreen || document.mozFullScreen || false;
 
-    element.requestFullScreen = element.requestFullScreen || element.webkitRequestFullScreen || element.mozRequestFullScreen || function () { return false; };
-    document.cancelFullScreen = document.cancelFullScreen || document.webkitCancelFullScreen || document.mozCancelFullScreen || function () { return false; };
+    element.requestFullScreen = element.requestFullScreen
+        || element.webkitRequestFullScreen
+        || element.mozRequestFullScreen
+        || function a() { return false; };
+    document.cancelFullScreen = document.cancelFullScreen
+        || document.webkitCancelFullScreen
+        || document.mozCancelFullScreen
+        || function a() { return false; };
 
     isFullscreen ? document.cancelFullScreen() : element.requestFullScreen();
 };