Let RBE node handle multiple msg.topic at the same time.

function/rbe/README.md

@@ -18,6 +18,9 @@ Usage
 A simple node to provide report by exception (RBE) and deadband function
 - only passes on data if it has changed.
 
+This works on a per **msg.topic** basis. This means that a single rbe node can
+handle multiple topics at the same time.
+
 ###RBE mode
 
 Outputs the **msg** if the **msg.payload** is different to the previous one.

function/rbe/package.json

@@ -1,6 +1,6 @@
 {
     "name"          : "node-red-node-rbe",
-    "version"       : "0.0.4",
+    "version"       : "0.0.5",
     "description"   : "A Node-RED node that provides report-by-exception (RBE) and deadband capability.",
     "dependencies"  : {
     },

function/rbe/rbe.html

@@ -38,6 +38,8 @@
     different to the previous one. Works on numbers and strings.</p>
     <p>In <b>deadband</b> mode the incoming payload should contain a parseable <i>number</i> and is
     output only if greater than + or - the <i>band gap</i> away from the previous output.</p>
+    <p><b>Note:</b> This works on a per <b>msg.topic</b> basis. This means that a single rbe node can
+handle multiple topics at the same time.</p>
 </script>
 
 <script type="text/javascript">

function/rbe/rbe.js

@@ -23,21 +23,22 @@ module.exports = function(RED) {
         this.gap = n.gap || 0;
         var node = this;
 
-        var previous = null;
+        node.previous = {};
         this.on("input",function(msg) {
             if (msg.hasOwnProperty("payload")) {
+                var t = msg.topic || "_no_topic";
                 if (this.func === "rbe") {
-                    if (msg.payload != previous) {
-                        previous = msg.payload;
+                    if (msg.payload != node.previous[t]) {
+                        node.previous[t] = msg.payload;
                         node.send(msg);
                     }
                 }
                 else {
                     var n = parseFloat(msg.payload);
                     if (!isNaN(n)) {
-                        if (previous == null) { previous = n - node.gap; }
-                        if (Math.abs(n - previous) >= node.gap) {
-                            previous = n;
+                        if (!node.previous.hasOwnProperty(t)) { node.previous[t] = n - node.gap; }
+                        if (Math.abs(n - node.previous[t]) >= node.gap) {
+                            node.previous[t] = n;
                             node.send(msg);
                         }
                     }