Processing the received messages in JavaScript

The onMessageArrived function receives a Paho.MQTT.Message instance in the message argument. The code prints a message to the console log indicating that a message has arrived with the destination topic and the payload string included in the message.destinationName and message.payloadString attributes.

Then, the code checks whether message.destionationName starts with APP.HomeAutomation.Manager.ledResultBaseTopic to make sure that the message's destination topic is the one defined for the results of the commands related to LEDs.

Note

In this case, the code only subscribes to the topic filters that we defined for publishing messages with the results of the commands related to LEDs. However, we include this code to understand how we should check the message.destinationName value when we subscribe to multiple topics that have different goals.

Then, the code retrieves the LED ID from the message's topic and saves it in the ledNumber variable. The code...