[Advanced Settings] Use better logic for detecting non-default values (…

…#11036)

* Use better logic for detecting non-default values

* Use a positive name for the boolean function to increase readability

* Adding comment describing conf.isCustom

* Make trash button logic consistent with default text logic

src/core_plugins/kibana/public/management/sections/settings/advanced_row.html

@@ -1,7 +1,7 @@
 <tr ng-class="conf.value === undefined ? 'default' : 'custom'">
   <td class="name">
     <b>{{conf.name}}</b>
-    <span class="smaller" ng-show="!conf.isCustom && conf.value !== undefined">
+    <span class="smaller" ng-show="!isDefaultValue(conf)">
       (Default: <i>{{conf.defVal == undefined || conf.defVal === '' ? 'null' : conf.defVal}}</i>)
     </span>
     <span class="smaller" ng-show="conf.isCustom">
@@ -115,7 +115,7 @@
     <button
       ng-if="!conf.editing"
       ng-click="clear(conf)"
-      ng-hide="conf.value === undefined"
+      ng-hide="isDefaultValue(conf)"
       class="btn btn-danger"
       aria-label="Clear"
     >

src/core_plugins/kibana/public/management/sections/settings/advanced_row.js

@@ -65,6 +65,14 @@ uiModules.get('apps/management')
         });
       };
 
+      $scope.isDefaultValue = (conf) => {
+        // conf.isCustom = custom setting, provided by user, so there is no notion of
+        // having a default or non-default value for it
+        return conf.isCustom
+          || conf.value === undefined
+          || conf.value === ''
+          || String(conf.value) === String(conf.defVal);
+      };
     }
   };
 });