feat: PresenceController - A utility controller to wire up other cont…

…rollers when an element comes into or leaves the DOM (#26)

docs/docs/controllers/presence_controller.mdx

@@ -0,0 +1,54 @@
+---
+id: PresenceController
+title: PresenceController
+---
+
+import NoActions from "../_partials/no-actions.md";
+import NoTargets from "../_partials/no-targets.md";
+import NoClasses from "../_partials/no-classes.md";
+import NoValues from "../_partials/no-values.md";
+
+## Purpose
+
+A utility controller to wire up other stimulus actions when an element comes into or leaves the document.
+
+
+## [Actions](https://stimulus.hotwire.dev/reference/actions)
+
+<NoActions/>
+
+## [Targets](https://stimulus.hotwire.dev/reference/targets)
+
+
+<NoTargets/>
+
+## [Classes](https://stimulus.hotwire.dev/reference/classes)
+
+
+<NoClasses/>
+
+## [Values](https://stimulus.hotwire.dev/reference/values)
+
+
+<NoValues/>
+
+## Events
+
+| Event | When | Dispatched on | `event.detail` |
+| --- | --- | --- |--- |
+|`presence:added` | When the element enters the DOM | the controller root element | - |
+|`presence:removed` | When the element leaves the DOM | the controller root element | - |
+
+## Side Effects
+
+None
+
+## How to Use
+
+<iframe
+  src="https://codesandbox.io/embed/presencecontroller-k7qgy?fontsize=14&hidenavigation=1&theme=dark"
+  style={{width: "100%", height: "500px", border: "0", borderRadius: "4px", overflow: "hidden"}}
+  sandbox="allow-forms allow-modals allow-popups allow-presentation allow-same-origin allow-scripts"
+/>
+
+

docs/sidebars.js

@@ -96,6 +96,7 @@ module.exports = {
           "controllers/AppearanceController",
           "controllers/IntervalController",
           "controllers/IntersectionController",
+          "controllers/PresenceController",
           "controllers/TimeoutController",
         ],
       },

src/controllers/utility/presence_controller.ts

@@ -0,0 +1,13 @@
+import {BaseController} from "../../utilities/base_controller";
+
+export class PresenceController extends BaseController {
+
+  connect() {
+    this.dispatch(this.el, "presence:added");
+  }
+
+  disconnect() {
+    this.dispatch(this.el, "presence:removed");
+  }
+
+}

src/index.ts

@@ -36,6 +36,7 @@ export {NavigateFormErrorsController} from "./controllers/forms/navigate_form_er
 export {NestedFormController} from "./controllers/forms/nested_form_controller";
 export {PasswordConfirmController} from "./controllers/forms/password_confirm_controller";
 export {PasswordPeekController} from "./controllers/forms/password_peek_controller";
+export {PresenceController} from "./controllers/utility/presence_controller";
 export {RemoteFormController} from "./controllers/forms/remote_form_controller";
 export {ResponsiveIframeBodyController, ResponsiveIframeWrapperController} from "./controllers/responsive_iframe_controller";
 export {ScrollIntoFocusController} from "./controllers/scroll/scroll_into_focus_controller";