diff --git a/README.md b/README.md
index 5f234f3..11b9d11 100644
--- a/README.md
+++ b/README.md
@@ -30,17 +30,17 @@ This node can be used to read one or multiple universes sent by sACN.
 
 #### Parameters:
 
-| Parameter  | Description                                                                                                                   | Possible Values                                                | Default Value                | Mandatory |
-| ---------- | ----------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------- | ---------------------------- | --------- |
-| universe   | The universe that is meant to be observed.                                                                                    | `\d+` (`1` to `63999`)                                         | `1`                          | yes       |
-| mode       | Defines whether the node returns the values of every read sACN package (passthrough mode), or merged values using HTP or LTP. | `passthrough`, `htp`, `ltp`                                    | `htp`                        | yes       |
-| output     | Defines whether the node sends only changed values or the whole universe.                                                      | `full`, `changes`                                              | `full`                       | yes       |
-| trigger    | Controls when a message is emitted: only on change, on every received packet, or on change plus a cyclic keepalive re-emit.    | `changes`, `always`, `interval`                                | `changes`                    | yes       |
-| interval   | Keepalive interval in milliseconds for the `interval` trigger; the full universe is re-emitted when no change arrives in time. | `\d+`                                                          | `1000`                       | no        |
-| clearOnUniverseChange | When the observed universe is switched at runtime, emit a full universe of zeros until real data for the new universe arrives. | `true`, `false`                                     | `false`                      | no        |
-| values     | Emit channel values as a percentage (0–100) or as raw DMX values (0–255).                                                     | `percent`, `absolute`                                          | `percent`                    | yes       |
-| IP-address | IP-Address of the network-interface that should be used for reading from sACN.                                                | `\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\` (_any valid ip-address_) | _empty_                      | no        |
-| port       | The network port which should be used for reading sACN.                                                                       | `\d+`                                                          | _empty_ (defaults to `5568`) | no        |
+| Parameter             | Description                                                                                                                    | Possible Values                                                | Default Value                | Mandatory |
+| --------------------- | ------------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------- | ---------------------------- | --------- |
+| universe              | The universe that is meant to be observed.                                                                                     | `\d+` (`1` to `63999`)                                         | `1`                          | yes       |
+| mode                  | Defines whether the node returns the values of every read sACN package (passthrough mode), or merged values using HTP or LTP.  | `passthrough`, `htp`, `ltp`                                    | `htp`                        | yes       |
+| output                | Defines whether the node sends only changed values or the whole universe.                                                      | `full`, `changes`                                              | `full`                       | yes       |
+| trigger               | Controls when a message is emitted: only on change, on every received packet, or on change plus a cyclic keepalive re-emit.    | `changes`, `always`, `interval`                                | `changes`                    | yes       |
+| interval              | Keepalive interval in milliseconds for the `interval` trigger; the full universe is re-emitted when no change arrives in time. | `\d+`                                                          | `1000`                       | no        |
+| clearOnUniverseChange | When the observed universe is switched at runtime, emit a full universe of zeros until real data for the new universe arrives. | `true`, `false`                                                | `false`                      | no        |
+| values                | Emit channel values as a percentage (0–100) or as raw DMX values (0–255).                                                      | `percent`, `absolute`                                          | `percent`                    | yes       |
+| IP-address            | IP-Address of the network-interface that should be used for reading from sACN.                                                 | `\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\` (_any valid ip-address_) | _empty_                      | no        |
+| port                  | The network port which should be used for reading sACN.                                                                        | `\d+`                                                          | _empty_ (defaults to `5568`) | no        |
 
 #### Input:
 
@@ -69,16 +69,16 @@ This node can be used to send one universe using sACN.
 
 #### Parameters:
 
-| Parameter   | Description                                                               | Possible Values                                                | Default Value                | Mandatory |
-| ----------- | ------------------------------------------------------------------------- | -------------------------------------------------------------- | ---------------------------- | --------- |
-| universe    | The universe that is meant to be observed.                                | `\d+` (`1` to `63999`)                                         | `1`                          | yes       |
-| source-name | The name for the sACN-sender that should be displayed within the network. | _any string below 50 characters_                               | `Node-RED`                   | yes       |
-| speed       | Defines the frequency for sending sACN-packages                           | `once (0Hz)`, `24Hz`, `27Hz`, `30Hz`, `40Hz`, `44Hz`           | `0Hz`                        | yes       |
-| priority    | The priority that should be used for the sACN-sender.                     | `\d+` (`1` to `200`)                                           | `100`                        | yes       |
-| values      | Interpret the payload as a percentage (0–100) or as raw DMX values (0–255). | `percent`, `absolute`                                         | `percent`                    | yes       |
-| blank-on-stop | Send an all-zero frame before closing so receivers go dark on stop.     | `true`, `false`                                                | `false`                      | no        |
-| IP-address  | IP-Address of the network-interface that should be used for sending sACN. | `\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\` (_any valid ip-address_) | _empty_                      | no        |
-| port        | The network port which should be used for reading sACN.                   | `\d+`                                                          | _empty_ (defaults to `5568`) | no        |
+| Parameter     | Description                                                                 | Possible Values                                                | Default Value                | Mandatory |
+| ------------- | --------------------------------------------------------------------------- | -------------------------------------------------------------- | ---------------------------- | --------- |
+| universe      | The universe that is meant to be observed.                                  | `\d+` (`1` to `63999`)                                         | `1`                          | yes       |
+| source-name   | The name for the sACN-sender that should be displayed within the network.   | _any string below 50 characters_                               | `Node-RED`                   | yes       |
+| speed         | Defines the frequency for sending sACN-packages                             | `once (0Hz)`, `24Hz`, `27Hz`, `30Hz`, `40Hz`, `44Hz`           | `0Hz`                        | yes       |
+| priority      | The priority that should be used for the sACN-sender.                       | `\d+` (`1` to `200`)                                           | `100`                        | yes       |
+| values        | Interpret the payload as a percentage (0–100) or as raw DMX values (0–255). | `percent`, `absolute`                                          | `percent`                    | yes       |
+| blank-on-stop | Send an all-zero frame before closing so receivers go dark on stop.         | `true`, `false`                                                | `false`                      | no        |
+| IP-address    | IP-Address of the network-interface that should be used for sending sACN.   | `\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\` (_any valid ip-address_) | _empty_                      | no        |
+| port          | The network port which should be used for reading sACN.                     | `\d+`                                                          | _empty_ (defaults to `5568`) | no        |
 
 #### Expected input:
 
diff --git a/build.js b/build.js
index b11e3fc..fcb3fa8 100644
--- a/build.js
+++ b/build.js
@@ -56,11 +56,16 @@ function buildNodeForm(node, source, target) {
 
   const initJSLines = initJS.split("\n");
   html.push('<script type="text/javascript">');
+  // wrap in an IIFE so top-level declarations (e.g. `const def`, helper functions)
+  // stay local; multiple node editor scripts share one global scope and would
+  // otherwise collide ("Identifier 'def' has already been declared").
+  html.push("    (function () {");
   initJSLines.forEach((line) => {
     if (line.length > 0) {
-      html.push(`    ${line}`);
+      html.push(`        ${line}`);
     }
   });
+  html.push("    })();");
   html.push("</script>");
 
   html.push("");
diff --git a/dist/nodes/sacn-in/sacn-in.html b/dist/nodes/sacn-in/sacn-in.html
index aae65de..4f15d62 100644
--- a/dist/nodes/sacn-in/sacn-in.html
+++ b/dist/nodes/sacn-in/sacn-in.html
@@ -172,121 +172,123 @@ <h3>References</h3>
     </ul>
 </script>
 <script type="text/javascript">
-    function populateInterfaceOptions() {
-        const list = document.getElementById("node-input-interface-options");
-        if (!list) {
-            return;
-        }
-        $.getJSON("sacn/interfaces", (interfaces) => {
-            list.replaceChildren();
-            interfaces.forEach((iface) => {
-                const option = document.createElement("option");
-                option.value = iface.address;
-                option.label = `${iface.name} (${iface.address})`;
-                list.appendChild(option);
+    (function () {
+        function populateInterfaceOptions() {
+            const list = document.getElementById("node-input-interface-options");
+            if (!list) {
+                return;
+            }
+            $.getJSON("sacn/interfaces", (interfaces) => {
+                list.replaceChildren();
+                interfaces.forEach((iface) => {
+                    const option = document.createElement("option");
+                    option.value = iface.address;
+                    option.label = `${iface.name} (${iface.address})`;
+                    list.appendChild(option);
+                });
             });
-        });
-    }
-    function toInt(value) {
-        if (typeof value === "number") {
-            return value;
         }
-        if (typeof value === "string") {
-            return parseInt(value, 10);
+        function toInt(value) {
+            if (typeof value === "number") {
+                return value;
+            }
+            if (typeof value === "string") {
+                return parseInt(value, 10);
+            }
+            return NaN;
         }
-        return NaN;
-    }
-    function isValidInterface(value) {
-        if (typeof value !== "string" || value === "") {
-            return true;
+        function isValidInterface(value) {
+            if (typeof value !== "string" || value === "") {
+                return true;
+            }
+            return /^(\d{1,3}\.){3}\d{1,3}$/.test(value);
         }
-        return /^(\d{1,3}\.){3}\d{1,3}$/.test(value);
-    }
-    function isValidUniverse(value) {
-        const n = toInt(value);
-        return !isNaN(n) && n >= 1 && n <= 63999;
-    }
-    function isValidPort(value) {
-        if (value === undefined || value === null || value === "") {
-            return true;
+        function isValidUniverse(value) {
+            const n = toInt(value);
+            return !isNaN(n) && n >= 1 && n <= 63999;
         }
-        const n = toInt(value);
-        return !isNaN(n) && n >= 1 && n <= 65535;
-    }
-    const def = {
-        category: "sACN",
-        color: "#dcc515",
-        defaults: {
-            name: {
-                value: "",
-            },
-            universe: {
-                value: 1,
-                required: true,
-                validate: function (v) {
-                    return isValidUniverse(v);
+        function isValidPort(value) {
+            if (value === undefined || value === null || value === "") {
+                return true;
+            }
+            const n = toInt(value);
+            return !isNaN(n) && n >= 1 && n <= 65535;
+        }
+        const def = {
+            category: "sACN",
+            color: "#dcc515",
+            defaults: {
+                name: {
+                    value: "",
                 },
-            },
-            port: {
-                value: undefined,
-                required: false,
-                validate: function (v) {
-                    return isValidPort(v);
+                universe: {
+                    value: 1,
+                    required: true,
+                    validate: function (v) {
+                        return isValidUniverse(v);
+                    },
                 },
-            },
-            interface: {
-                value: "",
-                required: false,
-                validate: function (v) {
-                    return isValidInterface(v);
+                port: {
+                    value: undefined,
+                    required: false,
+                    validate: function (v) {
+                        return isValidPort(v);
+                    },
+                },
+                interface: {
+                    value: "",
+                    required: false,
+                    validate: function (v) {
+                        return isValidInterface(v);
+                    },
+                },
+                mode: {
+                    value: "htp",
+                    required: true,
+                },
+                output: {
+                    value: "full",
+                    required: true,
+                },
+                trigger: {
+                    value: "changes",
+                    required: true,
+                },
+                interval: {
+                    value: 1000,
+                    required: true,
+                },
+                clearOnUniverseChange: {
+                    value: false,
+                },
+                values: {
+                    value: "percent",
+                    required: true,
                 },
             },
-            mode: {
-                value: "htp",
-                required: true,
-            },
-            output: {
-                value: "full",
-                required: true,
-            },
-            trigger: {
-                value: "changes",
-                required: true,
-            },
-            interval: {
-                value: 1000,
-                required: true,
+            inputs: 1,
+            outputs: 1,
+            paletteLabel: "sACN in",
+            icon: "sacn-in.svg",
+            label: function () {
+                return this.name || `sACN in · U${this.universe}`;
             },
-            clearOnUniverseChange: {
-                value: false,
+            labelStyle: function () {
+                return this.name ? "node_label_italic" : "";
             },
-            values: {
-                value: "percent",
-                required: true,
+            oneditprepare: function () {
+                const select = document.getElementById("node-input-trigger");
+                const row = document.getElementById("row-interval");
+                const toggleInterval = () => {
+                    if (row) {
+                        row.style.display = select?.value === "interval" ? "" : "none";
+                    }
+                };
+                select?.addEventListener("change", toggleInterval);
+                toggleInterval();
+                populateInterfaceOptions();
             },
-        },
-        inputs: 1,
-        outputs: 1,
-        paletteLabel: "sACN in",
-        icon: "sacn-in.svg",
-        label: function () {
-            return this.name || `sACN in · U${this.universe}`;
-        },
-        labelStyle: function () {
-            return this.name ? "node_label_italic" : "";
-        },
-        oneditprepare: function () {
-            const select = document.getElementById("node-input-trigger");
-            const row = document.getElementById("row-interval");
-            const toggleInterval = () => {
-                if (row) {
-                    row.style.display = select?.value === "interval" ? "" : "none";
-                }
-            };
-            select?.addEventListener("change", toggleInterval);
-            toggleInterval();
-            populateInterfaceOptions();
-        },
-    };
-    RED.nodes.registerType("sacn-in", def);
+        };
+        RED.nodes.registerType("sacn-in", def);
+    })();
 </script>
diff --git a/dist/nodes/sacn-out/sacn-out.html b/dist/nodes/sacn-out/sacn-out.html
index 9da8b1a..8fdfda5 100644
--- a/dist/nodes/sacn-out/sacn-out.html
+++ b/dist/nodes/sacn-out/sacn-out.html
@@ -117,108 +117,110 @@ <h3>References</h3>
     </ul>
 </script>
 <script type="text/javascript">
-    function populateInterfaceOptions() {
-        const list = document.getElementById("node-input-interface-options");
-        if (!list) {
-            return;
-        }
-        $.getJSON("sacn/interfaces", (interfaces) => {
-            list.replaceChildren();
-            interfaces.forEach((iface) => {
-                const option = document.createElement("option");
-                option.value = iface.address;
-                option.label = `${iface.name} (${iface.address})`;
-                list.appendChild(option);
+    (function () {
+        function populateInterfaceOptions() {
+            const list = document.getElementById("node-input-interface-options");
+            if (!list) {
+                return;
+            }
+            $.getJSON("sacn/interfaces", (interfaces) => {
+                list.replaceChildren();
+                interfaces.forEach((iface) => {
+                    const option = document.createElement("option");
+                    option.value = iface.address;
+                    option.label = `${iface.name} (${iface.address})`;
+                    list.appendChild(option);
+                });
             });
-        });
-    }
-    function toInt(value) {
-        if (typeof value === "number") {
-            return value;
         }
-        if (typeof value === "string") {
-            return parseInt(value, 10);
+        function toInt(value) {
+            if (typeof value === "number") {
+                return value;
+            }
+            if (typeof value === "string") {
+                return parseInt(value, 10);
+            }
+            return NaN;
         }
-        return NaN;
-    }
-    function isValidInterface(value) {
-        if (typeof value !== "string" || value === "") {
-            return true;
+        function isValidInterface(value) {
+            if (typeof value !== "string" || value === "") {
+                return true;
+            }
+            return /^(\d{1,3}\.){3}\d{1,3}$/.test(value);
         }
-        return /^(\d{1,3}\.){3}\d{1,3}$/.test(value);
-    }
-    function isValidUniverse(value) {
-        const n = toInt(value);
-        return !isNaN(n) && n >= 1 && n <= 63999;
-    }
-    function isValidPort(value) {
-        if (value === undefined || value === null || value === "") {
-            return true;
+        function isValidUniverse(value) {
+            const n = toInt(value);
+            return !isNaN(n) && n >= 1 && n <= 63999;
         }
-        const n = toInt(value);
-        return !isNaN(n) && n >= 1 && n <= 65535;
-    }
-    const def = {
-        category: "sACN",
-        color: "#dcc515",
-        defaults: {
-            name: {
-                value: "",
-            },
-            universe: {
-                value: 1,
-                required: true,
-                validate: function (v) {
-                    return isValidUniverse(v);
+        function isValidPort(value) {
+            if (value === undefined || value === null || value === "") {
+                return true;
+            }
+            const n = toInt(value);
+            return !isNaN(n) && n >= 1 && n <= 65535;
+        }
+        const def = {
+            category: "sACN",
+            color: "#dcc515",
+            defaults: {
+                name: {
+                    value: "",
                 },
-            },
-            port: {
-                value: undefined,
-                required: false,
-                validate: function (v) {
-                    return isValidPort(v);
+                universe: {
+                    value: 1,
+                    required: true,
+                    validate: function (v) {
+                        return isValidUniverse(v);
+                    },
                 },
-            },
-            interface: {
-                value: "",
-                required: false,
-                validate: function (v) {
-                    return isValidInterface(v);
+                port: {
+                    value: undefined,
+                    required: false,
+                    validate: function (v) {
+                        return isValidPort(v);
+                    },
+                },
+                interface: {
+                    value: "",
+                    required: false,
+                    validate: function (v) {
+                        return isValidInterface(v);
+                    },
+                },
+                speed: {
+                    value: 0,
+                    required: true,
+                },
+                priority: {
+                    value: 100,
+                    required: true,
+                },
+                sourceName: {
+                    value: "Node-RED",
+                    required: true,
+                },
+                blankOnClose: {
+                    value: false,
+                },
+                values: {
+                    value: "percent",
+                    required: true,
                 },
             },
-            speed: {
-                value: 0,
-                required: true,
-            },
-            priority: {
-                value: 100,
-                required: true,
-            },
-            sourceName: {
-                value: "Node-RED",
-                required: true,
+            inputs: 1,
+            outputs: 0,
+            paletteLabel: "sACN out",
+            icon: "sacn-out.svg",
+            label: function () {
+                return this.name || `sACN out · U${this.universe}`;
             },
-            blankOnClose: {
-                value: false,
+            labelStyle: function () {
+                return this.name ? "node_label_italic" : "";
             },
-            values: {
-                value: "percent",
-                required: true,
+            oneditprepare: function () {
+                populateInterfaceOptions();
             },
-        },
-        inputs: 1,
-        outputs: 0,
-        paletteLabel: "sACN out",
-        icon: "sacn-out.svg",
-        label: function () {
-            return this.name || `sACN out · U${this.universe}`;
-        },
-        labelStyle: function () {
-            return this.name ? "node_label_italic" : "";
-        },
-        oneditprepare: function () {
-            populateInterfaceOptions();
-        },
-    };
-    RED.nodes.registerType("sacn-out", def);
+        };
+        RED.nodes.registerType("sacn-out", def);
+    })();
 </script>
diff --git a/dist/nodes/scene-controller/scene-controller.html b/dist/nodes/scene-controller/scene-controller.html
index 201436a..812dccd 100644
--- a/dist/nodes/scene-controller/scene-controller.html
+++ b/dist/nodes/scene-controller/scene-controller.html
@@ -79,28 +79,30 @@ <h3>References</h3>
     </ul>
 </script>
 <script type="text/javascript">
-    const def = {
-        category: "sACN",
-        color: "#dcc515",
-        defaults: {
-            name: {
-                value: "Scene-Controller",
+    (function () {
+        const def = {
+            category: "sACN",
+            color: "#dcc515",
+            defaults: {
+                name: {
+                    value: "Scene-Controller",
+                },
+                values: {
+                    value: "percent",
+                    required: true,
+                },
             },
-            values: {
-                value: "percent",
-                required: true,
+            inputs: 1,
+            outputs: 1,
+            paletteLabel: "Scene-Controller",
+            icon: "scene-controller.svg",
+            label: function () {
+                return this.name || "Scene-Controller";
             },
-        },
-        inputs: 1,
-        outputs: 1,
-        paletteLabel: "Scene-Controller",
-        icon: "scene-controller.svg",
-        label: function () {
-            return this.name || "Scene-Controller";
-        },
-        labelStyle: function () {
-            return this.name ? "node_label_italic" : "";
-        },
-    };
-    RED.nodes.registerType("scene-controller", def);
+            labelStyle: function () {
+                return this.name ? "node_label_italic" : "";
+            },
+        };
+        RED.nodes.registerType("scene-controller", def);
+    })();
 </script>