added filtering to nlu engine

lib/nlu/bundles/engines/regexp/nlu.js

@@ -65,7 +65,25 @@ class Nlu extends Base {
             ' confidence ' + intentity.getMaxIntentConfidence().toFixed(3) +
             ' ' + this.name + ' [' + intentity.getIntentName() + ', ' + intentity.getNumOfEntities() +
             '] ' + time.toFixed(3) + 'ms');
-        // No match
+
+        // filtering intents according to the intents.json file
+        const intent = intentity.getIntentName();
+        if (intent !== undefined) {
+            // Visibility check
+            if (intent.visibility === 'hidden') {
+                intentity.removeIntent(intent);
+            }
+            // Entities fullfilment
+            if (intent.entities) {
+                for (const entity of intent.entities) {
+                    if (entity.required) {
+                        if (!intentity.getEntity(entity.name)) {
+                            intentity.removeIntent((intent));
+                        }
+                    }
+                }
+            }
+        }
         instrument.exitTime(request, "regexp", "evaluate");
         cb(null, intentity);
     }

lib/nlu/intentity.js

@@ -88,6 +88,13 @@ Intentity.prototype.getIntentName = function (index) {
     return null;
 };
 
+Intentity.prototype.removeIntent = function(intentName) {
+    let index = this.intents.indexOf(intentName);
+    if(index > -1) {
+        this.intents.splice(index, 1);
+    }
+};
+
 Intentity.prototype.getIntents = function () {
     return this.intents;
 };