diff --git a/demo/public/party.css b/demo/public/party.css
index c7d9524..70433af 100644
--- a/demo/public/party.css
+++ b/demo/public/party.css
@@ -120,3 +120,16 @@ body {
   text-align: center;
   vertical-align: center;
 }
+
+#grid {
+  transition: background-color 0.5s ease;
+}
+
+.flash-animation {
+  animation: flashRed 0.5s ease;
+}
+
+@keyframes flashRed {
+  0%   { background-color: #e55; }
+  100% { background-color: white; }
+  }
diff --git a/demo/src/app/views/websockets.zig b/demo/src/app/views/websockets.zig
index 28ee8b1..04eced0 100644
--- a/demo/src/app/views/websockets.zig
+++ b/demo/src/app/views/websockets.zig
@@ -21,7 +21,7 @@ pub const Channel = struct {
             game.evaluate();
 
             if (game.victor != null) {
-                try channel.publish(.{ .err = "Game is already over." });
+                try channel.invoke(.game_over, .{});
                 return;
             } else {
                 try movePlayer(channel, &game, cells, cell);
diff --git a/demo/src/app/views/websockets/index.zmpl b/demo/src/app/views/websockets/index.zmpl
index 5ca5202..738ce9d 100644
--- a/demo/src/app/views/websockets/index.zmpl
+++ b/demo/src/app/views/websockets/index.zmpl
@@ -5,13 +5,23 @@
         stateChangedCallbacks: [],
         messageCallbacks: [],
         invokeCallbacks: {},
+        elementMap: {},
+        transformerMap: {},
+        transformers: {},
         onStateChanged: function(callback) { this.stateChangedCallbacks.push(callback); },
         onMessage: function(callback) { this.messageCallbacks.push(callback); },
-        receive: function(event, callback) {
-            if (Object.hasOwn(this.invokeCallbacks, event)) {
-                this.invokeCallbacks[event].push(callback);
+        transform: function(ref, callback) {
+            if (Object.hasOwn(this.transformers, ref)) {
+                this.transformers[ref].push(callback);
             } else {
-                this.invokeCallbacks[event] = [callback];
+                this.transformers[ref] = [callback];
+            }
+        },
+        receive: function(ref, callback) {
+            if (Object.hasOwn(this.invokeCallbacks, ref)) {
+                this.invokeCallbacks[ref].push(callback);
+            } else {
+                this.invokeCallbacks[ref] = [callback];
             }
         },
         publish: function(data) {
@@ -21,76 +31,122 @@
             }
         },
     };
-</script>
+
+    (() => {
 
 @if (context.request) |request|
-    @if (request.headers.get("host")) |host|
-        <script>
-            channel.websocket = new WebSocket('ws://{{host}}{{request.path.base_path}}');
-            channel.websocket.addEventListener("message", (event) => {
-                const state_tag = "__jetzig_channel_state__:";
-                const actions_tag = "__jetzig_actions__:";
-                const event_tag = "__jetzig_event__:";
+    const transform = (value, state, element) => {
+        const id = element.getAttribute('jetzig-id');
+        const key = id && channel.transformerMap[id];
+        const transformers = key && channel.transformers[key];
+        if (transformers) {
+            return transformers.reduce((acc, val) => val(acc), value);
+        } else {
+            return value === undefined || value == null ? '' : `${value}`
+        }
+    };
 
-                if (event.data.startsWith(state_tag)) {
-                    const state = JSON.parse(event.data.slice(state_tag.length));
-                    channel.stateChangedCallbacks.forEach((callback) => {
-                        callback(state);
-                    });
-                } else if (event.data.startsWith(event_tag)) {
-                    const data = JSON.parse(event.data.slice(event_tag.length));
-                    if (Object.hasOwn(channel.invokeCallbacks, data.method)) {
-                        channel.invokeCallbacks[data.method].forEach(callback => {
+    @if (request.headers.get("host")) |host|
+                channel.websocket = new WebSocket('ws://{{host}}{{request.path.base_path}}');
+                channel.websocket.addEventListener("message", (event) => {
+                    const state_tag = "__jetzig_channel_state__:";
+                    const actions_tag = "__jetzig_actions__:";
+                    const event_tag = "__jetzig_event__:";
+
+                    if (event.data.startsWith(state_tag)) {
+                        const state = JSON.parse(event.data.slice(state_tag.length));
+                        Object.entries(channel.elementMap).forEach(([ref, elements]) => {
+                            const value = reduceState(ref, state);
+                            elements.forEach(element => element.innerHTML = transform(value, state, element));
+                        });
+                        channel.stateChangedCallbacks.forEach((callback) => {
+                            callback(state);
+                        });
+                    } else if (event.data.startsWith(event_tag)) {
+                        const data = JSON.parse(event.data.slice(event_tag.length));
+                        if (Object.hasOwn(channel.invokeCallbacks, data.method)) {
+                            channel.invokeCallbacks[data.method].forEach(callback => {
+                                callback(data);
+                            });
+                        }
+                    } else if (event.data.startsWith(actions_tag)) {
+                        const data = JSON.parse(event.data.slice(actions_tag.length));
+                        data.actions.forEach(action => {
+                            channel.actions[action.name] = (...params) => {
+                                if (action.params.length != params.length) {
+                                    throw new Error(`Invalid params for action '${action.name}'`);
+                                }
+                                [...action.params].forEach((param, index) => {
+                                    const map = {
+                                        s: "string",
+                                        b: "boolean",
+                                        i: "number",
+                                        f: "number",
+                                    };
+                                    if (map[param] !== typeof params[index]) {
+                                        throw new Error(`Incorrect argument type for argument ${index} in '${action.name}'. Expected: ${map[param]}, found ${typeof params[index]}`);
+                                    }
+                                });
+
+                                channel.websocket.send(`_invoke:${action.name}:${JSON.stringify(params)}`);
+                            };
+                        });
+                    } else {
+                        const data = JSON.parse(event.data);
+                        channel.messageCallbacks.forEach((callback) => {
                             callback(data);
                         });
                     }
-                } else if (event.data.startsWith(actions_tag)) {
-                    const data = JSON.parse(event.data.slice(actions_tag.length));
-                    data.actions.forEach(action => {
-                        channel.actions[action.name] = (...params) => {
-                            if (action.params.length != params.length) {
-                                throw new Error(`Invalid params for action '${action.name}'`);
-                            }
-                            [...action.params].forEach((param, index) => {
-                                const map = {
-                                    s: "string",
-                                    b: "boolean",
-                                    i: "number",
-                                    f: "number",
-                                };
-                                if (map[param] !== typeof params[index]) {
-                                    throw new Error(`Incorrect argument type for argument ${index} in '${action.name}'. Expected: ${map[param]}, found ${typeof params[index]}`);
-                                }
-                            });
 
-                            channel.websocket.send(`_invoke:${action.name}:${JSON.stringify(params)}`);
-                        };
-                    });
-                } else {
-                    const data = JSON.parse(event.data);
-                    channel.messageCallbacks.forEach((callback) => {
-                        callback(data);
-                    });
-                }
+                });
 
-            });
-            @// channel.websocket.addEventListener("open", (event) => {
-            @//     // TODO
-            @//     channel.publish("websockets", {});
-            @// });
-        </script>
+                const reduceState = (ref, state) => {
+                    if (!ref.startsWith('$.')) throw new Error(`Unexpected ref format: ${ref}`);
+                    const args = ref.split('.');
+                    args.shift();
+                    const isNumeric = (string) => [...string].every(char => '0123456789'.includes(char));
+                    const isObject = (object) => object && typeof object === 'object';
+                    return args.reduce((acc, arg) => {
+                        if (isNumeric(arg)) {
+                            if (acc && Array.isArray(acc) && acc.length > arg) return acc[parseInt(arg)];
+                            return null;
+                        } else {
+                            if (acc && isObject(acc)) return acc[arg];
+                            return null;
+                        }
+                    }, state);
+                };
+
+                window.addEventListener('DOMContentLoaded', () => {
+                    document.querySelectorAll('[jetzig-connect]').forEach(element => {
+                        const ref = element.getAttribute('jetzig-connect');
+                        if (!channel.elementMap[ref]) channel.elementMap[ref] = [];
+                        const id = `jetzig-${crypto.randomUUID()}`;
+                        element.setAttribute('jetzig-id', id);
+                        channel.elementMap[ref].push(element);
+                        channel.transformerMap[id] = element.getAttribute('jetzig-transform');
+                    });
+                });
+
+                @// channel.websocket.addEventListener("open", (event) => {
+                @//     // TODO
+                @//     channel.publish("websockets", {});
+                @// });
     @end
 @end
 
+    })();
+</script>
+
 <div id="results-wrapper">
     <span class="trophy">&#127942;</span>
     <div id="results">
         <div>Player</div>
-        <div id="player-wins"></div>
+        <div id="player-wins" jetzig-connect="$.results.player"></div>
         <div>CPU</div>
-        <div id="cpu-wins"></div>
+        <div id="cpu-wins" jetzig-connect="$.results.cpu"></div>
         <div>Tie</div>
-        <div id="ties"></div>
+        <div id="ties" jetzig-connect="$.results.tie"></div>
     </div>
     <span class="trophy">&#127942;</span>
 </div>
@@ -98,15 +154,9 @@
 <div id="party-container"></div>
 
 <div class="board" id="board">
-    <div class="cell" jetzig-connect="$.cells.0" id="tic-tac-toe-cell-0" data-cell="0"></div>
-    <div class="cell" jetzig-connect="$.cells.1" id="tic-tac-toe-cell-1" data-cell="1"></div>
-    <div class="cell" jetzig-connect="$.cells.2" id="tic-tac-toe-cell-2" data-cell="2"></div>
-    <div class="cell" jetzig-connect="$.cells.3" id="tic-tac-toe-cell-3" data-cell="3"></div>
-    <div class="cell" jetzig-connect="$.cells.4" id="tic-tac-toe-cell-4" data-cell="4"></div>
-    <div class="cell" jetzig-connect="$.cells.5" id="tic-tac-toe-cell-5" data-cell="5"></div>
-    <div class="cell" jetzig-connect="$.cells.6" id="tic-tac-toe-cell-6" data-cell="6"></div>
-    <div class="cell" jetzig-connect="$.cells.7" id="tic-tac-toe-cell-7" data-cell="7"></div>
-    <div class="cell" jetzig-connect="$.cells.8" id="tic-tac-toe-cell-8" data-cell="8"></div>
+    @for (0..9) |index| {
+        <div class="cell" jetzig-connect="$.cells.{{index}}" jetzig-transform="cell" id="tic-tac-toe-cell-{{index}}" data-cell="{{index}}"></div>
+    }
 </div>
 
 <button id="reset-button">Reset Game</button>
@@ -118,19 +168,10 @@
 
 <script>
     channel.onStateChanged(state => {
-        document.querySelector("#player-wins").innerText = state.results.player;
-        document.querySelector("#cpu-wins").innerText = state.results.cpu;
-        document.querySelector("#ties").innerText = state.results.tie;
-
         if (!state.victor) {
-            const elem = document.querySelector("#victor");
-            elem.style.visibility = 'hidden';
+            const element = document.querySelector("#victor");
+            element.style.visibility = 'hidden';
         }
-
-        Object.entries(state.cells).forEach(([cell, state]) => {
-            const element = document.querySelector(`#tic-tac-toe-cell-${cell}`);
-            element.innerHTML = { player: "&#9992;&#65039;", cpu: "&#129422;" }[state] || "";
-        });
     });
 
     channel.onMessage(message => {
@@ -140,25 +181,35 @@
     });
 
     channel.receive("victor", (data) => {
-        console.log(data);
-        const elem = document.querySelector("#victor");
+        const element = document.querySelector("#victor");
         const emoji = {
             player: "&#9992;&#65039;",
             cpu: "&#129422;",
             tie: "&#129309;"
         }[data.params.type] || "";
-        elem.innerHTML = `&#127942; ${emoji} &#127942;`;
-        elem.style.visibility = 'visible';
+        element.innerHTML = `&#127942; ${emoji} &#127942;`;
+        element.style.visibility = 'visible';
         triggerPartyAnimation();
     });
 
+    channel.receive("game_over", (data) => {
+        const element = document.querySelector("#board");
+        element.classList.remove('flash-animation');
+        void element.offsetWidth;
+        element.classList.add('flash-animation');
+    });
+
+    channel.transform("cell", (value) => (
+        { player: "&#9992;&#65039;", cpu: "&#129422;" }[value] || ""
+    ));
+    document.querySelectorAll("#board div.cell").forEach(element => {
+        element.addEventListener("click", () => {
+            channel.actions.move(parseInt(element.dataset.cell));
+        });
+    });
+
     document.querySelector("#reset-button").addEventListener("click", () => {
         channel.actions.reset();
     });
 
-    document.querySelectorAll("#board div.cell").forEach(element => {
-        element.addEventListener("click", () => {
-            channel.actions.move(parseInt(element.dataset.cell));
-        });
-    });
 </script>