feat: added check on empy object

Added a check before sending MQTT empty objects.

Author: csarnataro

.gitignore

@@ -2,4 +2,5 @@ node_modules
 lib
 dist
 es
-.tmp
+.tmp
+misc

src/connection/Connection.ts

@@ -111,8 +111,11 @@ export class Connection implements IConnection {
       else valueToSend = value;
     });
 
-    // the condition `if (valueToSend !== {}) ` has been removed bc it always evaluates to true
-    messages.push({ topic, propertyName: current, value: valueToSend });
+    // If the message is an object, and it's empty, it makes no sense to send it
+    // All other messages (e.g. non-empty objects or primitives) must be sent
+    if (!(typeof valueToSend === 'object' && Object.keys(valueToSend).length == 0)) {
+      messages.push({ topic, propertyName: current, value: valueToSend });
+    }
 
     return messages;
   }

test/arduino-cloud.test.js

@@ -92,6 +92,12 @@ describe('Test the library basic functionalities', () => {
       await ArduinoIoTCloud.onPropertyValue(thingId, propertyBoolName, (value) => value === propertyBoolVal ? done() : null);
       sendPropertyAsDevice(deviceId, thingId, propertyBoolName, propertyBoolVal);
     });
+
+    it('Simulate client read boolean as FALSE property sent by device', async (done) => {
+      await ArduinoIoTCloud.onPropertyValue(thingId, propertyBoolName, (value) => !value ? done() : null);
+      sendPropertyAsDevice(deviceId, thingId, propertyBoolName, false);
+    });
+
   })
 });