From 548f45cd56ca249ca47ec94091ba5256dbba7e9f Mon Sep 17 00:00:00 2001
From: Nick O'Leary <nick.oleary@gmail.com>
Date: Sat, 13 Jan 2018 22:53:58 +0000
Subject: [PATCH] Publish null/undefined to mqtt as blank not toString Fixes
 #1521

---
 nodes/core/io/10-mqtt.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/nodes/core/io/10-mqtt.js b/nodes/core/io/10-mqtt.js
index c98a099f9..3f39dd3c9 100644
--- a/nodes/core/io/10-mqtt.js
+++ b/nodes/core/io/10-mqtt.js
@@ -291,7 +291,9 @@ module.exports = function(RED) {
 
         this.publish = function (msg) {
             if (node.connected) {
-                if (!Buffer.isBuffer(msg.payload)) {
+                if (msg.payload === null || msg.payload === undefined) {
+                    msg.payload = "";
+                } else if (!Buffer.isBuffer(msg.payload)) {
                     if (typeof msg.payload === "object") {
                         msg.payload = JSON.stringify(msg.payload);
                     } else if (typeof msg.payload !== "string") {