add mqtt listener

mqtt/utils/node_id_util.js

@@ -0,0 +1,23 @@
+class NodeIdUtil {
+
+    /**
+     * Converts the provided hex id to a numeric id, for example: !FFFFFFFF to 4294967295
+     * Anything else will be converted as is to a BigInt, for example "4294967295" to 4294967295
+     * @param hexIdOrNumber a node id in hex format with a prepended "!", or a numeric node id as a string or number
+     * @returns {bigint} the node id in numeric form
+     */
+    static convertToNumeric(hexIdOrNumber) {
+
+        // check if this is a hex id, and convert to numeric
+        if(hexIdOrNumber.toString().startsWith("!")){
+            return BigInt('0x' + hexIdOrNumber.replaceAll("!", ""));
+        }
+
+        // convert string or number to numeric
+        return BigInt(hexIdOrNumber);
+
+    }
+
+}
+
+module.exports = NodeIdUtil;