Add custom tile features documentation (#1680)

* Add custom tile features documentation

* Feedbacks

docs/frontend/custom-ui/custom-card.md

@@ -22,12 +22,12 @@ class ContentCardExample extends HTMLElement {
           <div class="card-content"></div>
         </ha-card>
       `;
-      this.content = this.querySelector('div');
+      this.content = this.querySelector("div");
     }
 
     const entityId = this.config.entity;
     const state = hass.states[entityId];
-    const stateStr = state ? state.state : 'unavailable';
+    const stateStr = state ? state.state : "unavailable";
 
     this.content.innerHTML = `
       The state of ${entityId} is ${stateStr}!
@@ -40,7 +40,7 @@ class ContentCardExample extends HTMLElement {
   // will render an error card.
   setConfig(config) {
     if (!config.entity) {
-      throw new Error('You need to define an entity');
+      throw new Error("You need to define an entity");
     }
     this.config = config;
   }
@@ -52,7 +52,7 @@ class ContentCardExample extends HTMLElement {
   }
 }
 
-customElements.define('content-card-example', ContentCardExample);
+customElements.define("content-card-example", ContentCardExample);
 ```
 
 ## Referencing your new card
@@ -106,7 +106,7 @@ import "https://unpkg.com/wired-toggle@0.8.0/wired-toggle.js?module";
 import {
   LitElement,
   html,
-  css
+  css,
 } from "https://unpkg.com/lit-element@2.0.1/lit-element.js?module";
 
 function loadCSS(url) {
@@ -123,14 +123,14 @@ class WiredToggleCard extends LitElement {
   static get properties() {
     return {
       hass: {},
-      config: {}
+      config: {},
     };
   }
 
   render() {
     return html`
       <wired-card elevation="2">
-        ${this.config.entities.map(ent => {
+        ${this.config.entities.map((ent) => {
           const stateObj = this.hass.states[ent];
           return stateObj
             ? html`
@@ -138,13 +138,11 @@ class WiredToggleCard extends LitElement {
                   ${stateObj.attributes.friendly_name}
                   <wired-toggle
                     .checked="${stateObj.state === "on"}"
-                    @change="${ev => this._toggle(stateObj)}"
+                    @change="${(ev) => this._toggle(stateObj)}"
                   ></wired-toggle>
                 </div>
               `
-            : html`
+            : html` <div class="not-found">Entity ${ent} not found.</div> `;
-                <div class="not-found">Entity ${ent} not found.</div>
-              `;
         })}
       </wired-card>
     `;
@@ -165,7 +163,7 @@ class WiredToggleCard extends LitElement {
 
   _toggle(state) {
     this.hass.callService("homeassistant", "toggle", {
-      entity_id: state.entity_id
+      entity_id: state.entity_id,
     });
   }
 
@@ -248,7 +246,6 @@ customElements.define('content-card-example', ContentCardExample);
 
 ```js
 class ContentCardEditor extends LitElement {
-
   setConfig(config) {
     this._config = config;
   }
@@ -256,7 +253,7 @@ class ContentCardEditor extends LitElement {
   configChanged(newConfig) {
     const event = new Event("config-changed", {
       bubbles: true,
-      composed: true
+      composed: true,
     });
     event.detail = { config: newConfig };
     this.dispatchEvent(event);
@@ -269,10 +266,125 @@ window.customCards.push({
   type: "content-card-example",
   name: "Content Card",
   preview: false, // Optional - defaults to false
-  description: "A custom card made by me!" // Optional
+  description: "A custom card made by me!", // Optional
 });
 ```
 
+## Tile features
+
+The tile card has support for "features" to add quick actions to control the entity. We offer some built-in features, but you can build and use your own using similar way than defining custom cards.
+
+Below is an example of a custom tile feature for [button entity](/docs/core/entity/button/).
+
+![Screenshot of the custom tile feature example](/img/en/frontend/dashboard-custom-tile-feature-screenshot.png)
+
+```js
+import {
+  LitElement,
+  html,
+  css,
+} from "https://unpkg.com/lit-element@2.0.1/lit-element.js?module";
+
+const supportsButtonPressTileFeature = (stateObj) => {
+  const domain = stateObj.entity_id.split(".")[0];
+  return domain === "button";
+};
+
+class ButtonPressTileFeature extends LitElement {
+  static get properties() {
+    return {
+      hass: undefined,
+      config: undefined,
+      stateObj: undefined,
+    };
+  }
+
+  static getStubConfig() {
+    return {
+      type: "custom:button-press-tile-feature",
+      label: "Press",
+    };
+  }
+
+  setConfig(config) {
+    if (!config) {
+      throw new Error("Invalid configuration");
+    }
+    this.config = config;
+  }
+
+  _press(ev) {
+    ev.stopPropagation();
+    this.hass.callService("button", "press", {
+      entity_id: this.stateObj.entity_id,
+    });
+  }
+
+  render() {
+    if (
+      !this.config ||
+      !this.hass ||
+      !this.stateObj ||
+      !supportsButtonPressTileFeature(this.stateObj)
+    ) {
+      return null;
+    }
+
+    return html`
+      <div class="container">
+        <button class="button" @click=${this._press}>
+          ${this.config.label || "Press"}
+        </button>
+      </div>
+    `;
+  }
+
+  static get styles() {
+    return css`
+      .container {
+        display: flex;
+        flex-direction: row;
+        padding: 0 12px 12px 12px;
+        width: auto;
+      }
+      .button {
+        display: block;
+        width: 100%;
+        height: 40px;
+        border-radius: 6px;
+        border: none;
+        background-color: #eeeeee;
+        cursor: pointer;
+        transition: background-color 180ms ease-in-out;
+      }
+      .button:hover {
+        background-color: #dddddd;
+      }
+      .button:focus {
+        background-color: #cdcdcd;
+      }
+    `;
+  }
+}
+
+customElements.define("button-press-tile-feature", ButtonPressTileFeature);
+
+window.customTileFeatures = window.customTileFeatures || [];
+window.customTileFeatures.push({
+  type: "button-press-tile-feature",
+  name: "Button press",
+  supported: supportsButtonPressTileFeature, // Optional
+  configurable: true, // Optional - defaults to false
+});
+```
+
+The only difference with custom cards is the graphical configuration option.
+To have it displayed in the tile card editor, you must add an object describing it to the array `window.customTileFeatures`.
+
+Required properties of the object are `type` and `name`. It is recommended to define the `supported` option with a function so the editor can only propose the feature if it is compatible with the selected entity in the tile card. Set `configurable` to `true` if your entity has additional configuration (e.g. `label` option in the example above) so the editor.
+
+Also, the static functions `getConfigElement` and `getStubConfig` work the same as with normal custom maps.
+
 ## Advanced Resources
 
 Community Maintained Boilerplate Card - Advanced Template (Typescript, Rollup, Linting, etc.)