Add change node to core/logic - allows simple(r) manipulation of some payloads and msg.properties to save having to write functions for these basic tasks. You can replace contents (regex based or simple swap), and add, modify or delete proerties.

nodes/core/logic/15-change.html

@@ -0,0 +1,111 @@
+<!--
+  Copyright 2013 IBM Corp.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+
+<script type="text/x-red" data-template-name="change">
+    <div>
+        <select id="node-input-action" style="width:95%; margin-right:5px;">
+            <option value="change">Change the value of the property</option>
+            <!-- <option value="replace">Replace value of property</option> -->
+            <option value="replace">Add or replace property</option>
+            <option value="delete">Delete property</option>
+        </select>
+    </div>
+    <div class="form-row" style="padding-top:10px;" id="node-prop1-row">
+        <label id="node-input-todo">called</label>msg.<input type="text" id="node-input-property" style="width: 63%;"/>
+    </div>
+    <div class="form-row" id="node-from-row">
+        <label id="node-input-f">if it contains</label>
+        <input type="text" id="node-input-from" placeholder="this"/>
+    </div>
+    <div class="form-row" id="node-to-row">
+        <label id="node-input-t">replace with</label>
+        <input type="text" id="node-input-to" placeholder="that"/>
+    </div>
+    <br/>
+    <div class="form-row">
+        <label for="node-input-name"><i class="icon-tag"></i> Name</label>
+        <input type="text" id="node-input-name" placeholder="Name">
+    </div>
+    <div class="form-tips" id="node-tip"></div>
+</script>
+
+<script type="text/x-red" data-help-name="change">
+    <p>A simple function node to change, replace, add or delete properties of a message.</p>
+    <p>When a message arrives, the selected property is modified by the defined rules.
+    The message is then sent to the output.</p>
+    <p><b>Note:</b> Replace only operates on <b>strings</b>. Anything else will be passed straight through.</p>
+</script>
+
+<script type="text/javascript">
+    RED.nodes.registerType('change', {
+        color: "#E2D96E",
+        category: 'function',
+        defaults: {
+            action: {value:"change",required:true},
+            property: {value:"payload"},
+            from: {value:""},
+            to: {value:""},
+            name: {value:""}
+        },
+        inputs: 1,
+        outputs: 1,
+        icon: "swap.png",
+        label: function() {
+            return this.name || this.action || "change";
+        },
+        labelStyle: function() {
+            return this.name ? "node_label_italic" : "";
+        },
+        oneditprepare: function() {
+            $("#node-input-action").change( function() {
+                var a = $("#node-input-action").val();
+                if (a === "replace") {
+                    $("#node-input-todo").html("called");
+                    //$("#node-input-f").html("name");
+                    $("#node-input-t").html("with value");
+                    $("#node-from-row").hide();
+                    $("#node-to-row").show();
+                    $("#node-tip").html("Tip: expects a new property name and either a fixed value OR the full name of another msg.property eg: msg.sentiment.score");
+                }
+                if (a === "delete") {
+                    $("#node-input-todo").html("called");
+                    //$("#node-input-f").html("called");
+                    //$("#node-input-t").html("to");
+                    $("#node-from-row").hide();
+                    $("#node-to-row").hide();
+                    $("#node-tip").html("Tip: deletes the named property and all sub-properties");
+                }
+                if (a === "change") {
+                    $("#node-input-todo").html("called");
+                    $("#node-input-f").html("If it contains");
+                    $("#node-input-t").html("replace with");
+                    $("#node-from-row").show();
+                    $("#node-to-row").show();
+                    $("#node-tip").html("Tip: <i>if it contains</i> can be a regex, likewise <i>replace with</i> can accept regex results. Only works on strings.");
+                }
+                //if (a === "replace") {
+                 //   $("#node-input-todo").html("called");
+                 //   //$("#node-input-f").html("with");
+                 //   $("#node-input-t").html("with");
+                 //   $("#node-from-row").hide();
+                 //   $("#node-to-row").show();
+                 //   $("#node-tip").html("Tip: accepts either a fixed value OR the full name of another msg.property eg: msg.sentiment.score");
+                //}
+            });
+            $("#node-input-action").change();
+        }
+    });
+</script>

nodes/core/logic/15-change.js

@@ -0,0 +1,66 @@
+/**
+ * Copyright 2013 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+var RED = require(process.env.NODE_RED_HOME + "/red/red");
+
+function ChangeNode(n) {
+    RED.nodes.createNode(this, n);
+    this.action = n.action;
+    this.property = n.property || "";
+    this.from = n.from || " ";
+    this.to = n.to || " ";
+    var node = this;
+
+    var makeNew = function( stem, path, value ) {
+        var lastPart = (arguments.length === 3) ? path.pop() : false;
+        for (var i = 0; i < path.length; i++) {
+            stem = stem[path[i]] = stem[path[i]] || {};
+        }
+        if (lastPart) { stem = stem[lastPart] = value; }
+        return stem;
+    };
+
+    this.on('input', function (msg) {
+        if (node.action == "change") {
+            node.re = new RegExp(this.from, "g");
+            if (typeof msg[node.property] === "string") {
+                msg[node.property] = (msg[node.property]).replace(node.re, node.to);
+            }
+        }
+        //else if (node.action == "replace") {
+            //if (node.to.indexOf("msg.") == 0) {
+                //msg[node.property] = eval(node.to);
+            //}
+            //else {
+                //msg[node.property] = node.to;
+            //}
+        //}
+        else if (node.action == "replace") {
+            if (node.to.indexOf("msg.") == 0) {
+                makeNew( msg, node.property.split("."), eval(node.to) );
+            }
+            else {
+                makeNew( msg, node.property.split("."), node.to );
+            }
+            //makeNew( msg, node.property.split("."), node.to );
+        }
+        else if (node.action == "delete") {
+            delete(msg[node.property]);
+        }
+        node.send(msg);
+    });
+}
+RED.nodes.registerType("change", ChangeNode);