NIFI-159:

- Allowing optional properties to be reset.
- Used null to represent an unset value as previously it was considered undefined. When undefined, the property was not being included in the serialized configuration.

nar-bundles/framework-bundle/framework/web/nifi-web-ui/src/main/webapp/js/nf/canvas/nf-processor-property-combo-editor.js

@@ -51,6 +51,7 @@ nf.ProcessorPropertyComboEditor = function (args) {
                 optionClass: 'unset'
             });
         }
+        if ($.isArray(allowableValues)) {
             $.each(allowableValues, function (i, allowableValue) {
                 options.push({
                     text: allowableValue.displayName,
@@ -58,6 +59,7 @@ nf.ProcessorPropertyComboEditor = function (args) {
                     description: nf.Common.escapeHtml(allowableValue.description)
                 });
             });
+        }
 
         // ensure the options there is at least one option
         if (options.length === 0) {

nar-bundles/framework-bundle/framework/web/nifi-web-ui/src/main/webapp/js/nf/canvas/nf-processor-property-nfel-editor.js

@@ -160,18 +160,13 @@ nf.ProcessorPropertyNfelEditor = function (args) {
                 // otherwise if the property is required
                 if (nf.ProcessorPropertyTable.isRequiredProperty(propertyDescriptor)) {
                     if (nf.Common.isBlank(propertyDescriptor.defaultValue)) {
-                        // reset to the previous value if available
-                        if (nf.Common.isDefinedAndNotNull(previousValue)) {
                         return previousValue;
-                        } else {
-                            return undefined;
-                        }
                     } else {
                         return propertyDescriptor.defaultValue;
                     }
                 } else {
                     // if the property is not required, clear the value
-                    return undefined;
+                    return null;
                 }
             }
         } else {

nar-bundles/framework-bundle/framework/web/nifi-web-ui/src/main/webapp/js/nf/canvas/nf-processor-property-table.js

@@ -40,7 +40,7 @@ nf.ProcessorPropertyTable = (function () {
                     hidden: false,
                     property: propertyName,
                     displayName: propertyName,
-                    previousValue: undefined,
+                    previousValue: null,
                     value: propertyValue,
                     type: 'userDefined'
                 });
@@ -377,7 +377,7 @@ nf.ProcessorPropertyTable = (function () {
             if (nf.Common.isDefinedAndNotNull(propertyDescriptor)) {
                 return propertyDescriptor.allowableValues;
             } else {
-                return undefined;
+                return null;
             }
         },
         /**
@@ -477,7 +477,7 @@ nf.ProcessorPropertyTable = (function () {
                         displayName = descriptor.displayName;
                         
                         // determine the value
-                        if (nf.Common.isUndefined(value) || nf.Common.isNull(value)) {
+                        if (nf.Common.isNull(value) && nf.Common.isDefinedAndNotNull(descriptor.defaultValue)) {
                             value = descriptor.defaultValue;
                         }
                     }

nar-bundles/framework-bundle/framework/web/nifi-web-ui/src/main/webapp/js/nf/canvas/nf-processor-property-text-editor.js

@@ -169,18 +169,13 @@ nf.ProcessorPropertyTextEditor = function (args) {
                 // otherwise if the property is required
                 if (nf.ProcessorPropertyTable.isRequiredProperty(propertyDescriptor)) {
                     if (nf.Common.isBlank(propertyDescriptor.defaultValue)) {
-                        // reset to the previous value if available
-                        if (nf.Common.isDefinedAndNotNull(previousValue)) {
                         return previousValue;
-                        } else {
-                            return undefined;
-                        }
                     } else {
                         return propertyDescriptor.defaultValue;
                     }
                 } else {
                     // if the property is not required, clear the value
-                    return undefined;
+                    return null;
                 }
             }
         } else {

nar-bundles/framework-bundle/framework/web/nifi-web-ui/src/main/webapp/js/nf/nf-processor-details.js

@@ -476,7 +476,7 @@ nf.ProcessorDetails = (function () {
                                 displayName = descriptor.displayName;
                                 
                                 // determine the value
-                                if (nf.Common.isUndefined(value) || nf.Common.isNull(value)) {
+                                if (nf.Common.isNull(value) && nf.Common.isDefinedAndNotNull(descriptor.defaultValue)) {
                                     value = descriptor.defaultValue;
                                 }
                             }