Add send nulls option

package.json

@@ -1,7 +1,7 @@
 {
   "description": "This package.json file is only used for installing npm dependencies. But this is not an installable node package, but a WireCloud operator. Take a look into src/config.xml for more details about this operator",
   "devDependencies": {
-    "grunt": "^1.0.4",
+    "grunt": "^1.1.0",
     "grunt-contrib-clean": "^2.0.0",
     "grunt-contrib-compress": "^1.6.0",
     "grunt-contrib-copy": "^1.0.0",
@@ -15,8 +15,8 @@
     "karma": "^4.4.1",
     "karma-chrome-launcher": "^3.1.0",
     "karma-coverage": "^2.0.1",
-    "karma-firefox-launcher": "^1.2.0",
-    "karma-jasmine": "^2.0.1",
+    "karma-firefox-launcher": "^1.3.0",
+    "karma-jasmine": "^3.1.1",
     "karma-junit-reporter": "^2.0.1",
     "mock-applicationmashup": "^1.0.0-g",
     "wirecloud-config-parser": "^0.2.2"

src/config.xml

@@ -1,5 +1,5 @@
 <?xml version='1.0' encoding='UTF-8'?>
-<operator xmlns="http://wirecloud.conwet.fi.upm.es/ns/macdescription/1" vendor="FISUDA" name="ngsi-entity-filter" version="0.1.0">
+<operator xmlns="http://wirecloud.conwet.fi.upm.es/ns/macdescription/1" vendor="FISUDA" name="ngsi-entity-filter" version="0.1.1">
 
     <details>
         <title>NGSI Entity filter</title>
@@ -22,8 +22,9 @@
     </requirements>
 
     <preferences>
-        <preference
-            name="types" type="text" label="Entity types" description="A comma separated list of Entity types to filter" default="" />
+        <preference name="types" type="text" label="Entity types" description="A comma separated list of Entity types to filter" default="" />
+        <preference name="send_nulls" type="boolean" label="Send Nulls" description="Enable this option to propagate null values when array is empty" default="false" />
+
     </preferences>
 
     <wiring>

src/js/main.js

@@ -17,6 +17,9 @@
                 return types.indexOf(e.type) !== -1;
             });
 
+            if (MashupPlatform.prefs.get('send_nulls') && new_entites.length == 0) {
+                new_entites = null;
+            }
             MashupPlatform.wiring.pushEvent("entityOutput", new_entites);
         }
     }

tests/js/NgsiEntityFilterSpec.js

@@ -10,7 +10,8 @@
             window.MashupPlatform = new MockMP({
                 type: 'operator',
                 prefs: {
-                    'types': 'test'
+                    'types': 'test',
+                    'send_nulls': false
                 },
                 inputs: ['entityInput'],
                 outputs: ['entityOutput']
@@ -46,6 +47,15 @@
             expect(MashupPlatform.wiring.pushEvent).toHaveBeenCalledWith('entityOutput', []);
         });
 
+        it("send nulls", function () {
+            MashupPlatform.prefs.set('types', '');
+            MashupPlatform.prefs.set('send_nulls', true);
+
+            ngsiEntityFilter([{'type': 'test'}, {'type': 'abc'}, {'type': 'xyz'}, {'type': '123'}]);
+
+            expect(MashupPlatform.wiring.pushEvent).toHaveBeenCalledWith('entityOutput', null);
+        });
+
         it("output endoint is not connected", function () {
             MashupPlatform.operator.outputs.entityOutput.disconnect();