feature #794 [Live] Dispatch browser events (weaverryan)

This PR was squashed before being merged into the 2.x branch.

Discussion
----------

[Live] Dispatch browser events

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Tickets       | None
| License       | MIT

Hi!

I figured we'd need this eventually :). While building an component that opens/closes a modal, I needed a way to close the modal from a `LiveAction` in PHP. The way to do that is to dispatch a DOM event from the action, then listen to that with a tiny bit of JavaScript that closes the modal. Modeled after Livewire, like with emit(). Super simple.

Also fixed a bug with `attributes.add()` on non-live components.

Cheers!

Commits
-------

e2ca326 [Live] Dispatch browser events

Author: weaverryan

src/LiveComponent/CHANGELOG.md

@@ -31,6 +31,8 @@ public User $user;
 
 -   You can now `emit()` events to communicate between components.
 
+-   You can now dispatch DOM/browser events from components.
+
 -   Boolean checkboxes are now supported. Of a checkbox does **not** have a
     `value` attribute, then the associated `LiveProp` will be set to a boolean
     when the input is checked/unchecked.

src/LiveComponent/assets/dist/Component/ElementDriver.d.ts

@@ -9,6 +9,10 @@ export interface ElementDriver {
         target: string | null;
         componentName: string | null;
     }>;
+    getBrowserEventsToDispatch(element: HTMLElement): Array<{
+        event: string;
+        payload: any;
+    }>;
 }
 export declare class StandardElementDriver implements ElementDriver {
     getModelName(element: HTMLElement): string | null;
@@ -21,4 +25,8 @@ export declare class StandardElementDriver implements ElementDriver {
         target: string | null;
         componentName: string | null;
     }>;
+    getBrowserEventsToDispatch(element: HTMLElement): Array<{
+        event: string;
+        payload: any;
+    }>;
 }

src/LiveComponent/assets/dist/live_controller.js

@@ -1962,6 +1962,7 @@ class Component {
         const newProps = this.elementDriver.getComponentProps(newElement);
         this.valueStore.reinitializeAllProps(newProps);
         const eventsToEmit = this.elementDriver.getEventsToEmit(newElement);
+        const browserEventsToDispatch = this.elementDriver.getBrowserEventsToDispatch(newElement);
         this.externalMutationTracker.handlePendingChanges();
         this.externalMutationTracker.stop();
         executeMorphdom(this.element, newElement, this.unsyncedInputsTracker.getUnsyncedInputs(), (element) => getValueFromElement(element, this.valueStore), Array.from(this.getChildren().values()), this.elementDriver.findChildComponentElement, this.elementDriver.getKeyFromElement, this.externalMutationTracker);
@@ -1980,6 +1981,12 @@ class Component {
             }
             this.emit(event, data, componentName);
         });
+        browserEventsToDispatch.forEach(({ event, payload }) => {
+            this.element.dispatchEvent(new CustomEvent(event, {
+                detail: payload,
+                bubbles: true,
+            }));
+        });
         this.hooks.triggerHook('render:finished', this);
     }
     calculateDebounce(debounce) {
@@ -2215,6 +2222,11 @@ class StandardElementDriver {
         const eventsJson = (_a = element.dataset.liveEmit) !== null && _a !== void 0 ? _a : '[]';
         return JSON.parse(eventsJson);
     }
+    getBrowserEventsToDispatch(element) {
+        var _a;
+        const eventsJson = (_a = element.dataset.liveBrowserDispatch) !== null && _a !== void 0 ? _a : '[]';
+        return JSON.parse(eventsJson);
+    }
 }
 
 class LoadingPlugin {

src/LiveComponent/assets/src/Component/ElementDriver.ts

@@ -19,6 +19,11 @@ export interface ElementDriver {
      * Given an element from a response, find all the events that should be emitted.
      */
     getEventsToEmit(element: HTMLElement): Array<{event: string, data: any, target: string|null, componentName: string|null }>;
+
+    /**
+     * Given an element from a response, find all the events that should be dispatched.
+     */
+    getBrowserEventsToDispatch(element: HTMLElement): Array<{event: string, payload: any }>;
 }
 
 export class StandardElementDriver implements ElementDriver {
@@ -51,4 +56,10 @@ export class StandardElementDriver implements ElementDriver {
 
         return JSON.parse(eventsJson);
     }
+
+    getBrowserEventsToDispatch(element: HTMLElement): Array<{event: string, payload: any }> {
+        const eventsJson = element.dataset.liveBrowserDispatch ?? '[]';
+
+        return JSON.parse(eventsJson);
+    }
 }

src/LiveComponent/assets/src/Component/index.ts

@@ -452,6 +452,7 @@ export default class Component {
         this.valueStore.reinitializeAllProps(newProps);
 
         const eventsToEmit = this.elementDriver.getEventsToEmit(newElement);
+        const browserEventsToDispatch = this.elementDriver.getBrowserEventsToDispatch(newElement);
 
         // make sure we've processed all external changes before morphing
         this.externalMutationTracker.handlePendingChanges();
@@ -489,6 +490,13 @@ export default class Component {
             this.emit(event, data, componentName);
         });
 
+        browserEventsToDispatch.forEach(({ event, payload }) => {
+            this.element.dispatchEvent(new CustomEvent(event, {
+                detail: payload,
+                bubbles: true,
+            }));
+        });
+
         this.hooks.triggerHook('render:finished', this);
     }
 

src/LiveComponent/assets/test/controller/dispatch-event.test.ts

@@ -0,0 +1,43 @@
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+'use strict';
+
+import {createTest, initComponent, shutdownTests} from '../tools';
+
+describe('LiveController Event Dispatching Tests', () => {
+    afterEach(() => {
+        shutdownTests()
+    });
+
+    it('dispatches events sent from an AJAX request', async () => {
+        const test = await createTest({ }, (data: any) => `
+            <div ${initComponent(data, {
+                name: 'simple-component',
+            })}>Simple Component!</div>
+        `);
+
+        let eventCalled = false;
+        test.element.addEventListener('fooEvent', (event: any) => {
+            eventCalled = true;
+            expect(event.detail).toEqual({ foo: 'bar' });
+        });
+
+        test.expectsAjaxCall()
+            .willReturn(() => `
+                <div ${initComponent({}, { browserDispatch: [
+                        { event: 'fooEvent', payload: { foo: 'bar' } }
+                    ]}
+                )}>Simple Component!</div>
+            `);
+
+        await test.component.render();
+        expect(eventCalled).toBe(true);
+    });
+});

src/LiveComponent/assets/test/tools.ts

@@ -427,6 +427,7 @@ export function initComponent(props: any = {}, controllerValues: any = {}) {
         ${controllerValues.id ? `data-live-id="${controllerValues.id}"` : ''}
         ${controllerValues.fingerprint ? `data-live-fingerprint-value="${controllerValues.fingerprint}"` : ''}
         ${controllerValues.listeners ? `data-live-listeners-value="${dataToJsonAttribute(controllerValues.listeners)}"` : ''}
+        ${controllerValues.browserDispatch ? `data-live-browser-dispatch="${dataToJsonAttribute(controllerValues.browserDispatch)}"` : ''}
     `;
 }
 

src/LiveComponent/doc/index.rst

@@ -2114,13 +2114,13 @@ There are three ways to emit an event:
         data-event="productAdded"
     >
 
-2. From your PHP component via ``ComponentEmitsTrait``::
+2. From your PHP component via ``ComponentToolsTrait``::
 
-    use Symfony\UX\LiveComponent\ComponentEmitsTrait;
+    use Symfony\UX\LiveComponent\ComponentToolsTrait;
 
     class MyComponent
     {
-        use ComponentEmitsTrait;
+        use ComponentToolsTrait;
 
         #[LiveAction]
         public function saveProduct()
@@ -2248,6 +2248,71 @@ Or, in PHP::
 
     $this->emitSelf('productAdded');
 
+Dispatching Browser/JavaScript Events
+-------------------------------------
+
+Sometimes you may want to dispatch a JavaScript event from your component. You
+could use this to signal, for example, that a modal should close::
+
+    use Symfony\UX\LiveComponent\ComponentToolsTrait;
+    // ...
+
+    class MyComponent
+    {
+        use ComponentToolsTrait;
+
+        #[LiveAction]
+        public function saveProduct()
+        {
+            // ...
+
+            $this->dispatchBrowserEvent('modal:close');
+        }
+    }
+
+This will dispatch a ``modal:close`` event on the top-level element of
+your component. It's often handy to listen to this event in a custom
+Stimulus controller - like this for Bootstrap's modal:
+
+.. code-block:: javascript
+
+    // assets/controllers/bootstrap-modal-controller.js
+    import { Controller } from '@hotwired/stimulus';
+    import { Modal } from 'bootstrap';
+
+    export default class extends Controller {
+        modal = null;
+
+        initialize() {
+            this.modal = Modal.getOrCreateInstance(this.element);
+            window.addEventListener('modal:close', () => this.modal.hide());
+        }
+    }
+
+Just make sure this controller is attached to the modal element:
+
+.. code-block:: html+twig
+
+    <div class="modal fade" {{ stimulus_controller('bootstrap-modal') }}">
+        <div class="modal-dialog">
+            ... content ...
+        </div>
+    </div>
+
+You can also pass data to the event::
+
+    $this->dispatchBrowserEvent('product:created', [
+        'product' => $product->getId(),
+    ]);
+
+This becomes the ``detail`` property of the event:
+
+.. code-block:: javascript
+
+    window.addEventListener('product:created', (event) => {
+        console.log(event.detail.product);
+    });
+
 Nested Components
 -----------------
 

src/LiveComponent/src/ComponentEmitsTrait.php renamed to src/LiveComponent/src/ComponentToolsTrait.php

@@ -14,11 +14,13 @@
 use Symfony\Contracts\Service\Attribute\Required;
 
 /**
+ * Trait with shortcut methods useful for live components.
+ *
  * @author Ryan Weaver <[email protected]>
  *
  * @experimental
  */
-trait ComponentEmitsTrait
+trait ComponentToolsTrait
 {
     private LiveResponder $liveResponder;
 
@@ -45,4 +47,9 @@ public function emitSelf(string $eventName, array $data = []): void
     {
         $this->liveResponder->emitSelf($eventName, $data);
     }
+
+    public function dispatchBrowserEvent(string $eventName, array $payload = []): void
+    {
+        $this->liveResponder->dispatchBrowserEvent($eventName, $payload);
+    }
 }

src/LiveComponent/src/LiveResponder.php

@@ -19,12 +19,15 @@
 final class LiveResponder
 {
     /**
-     * Key is the event name, value is an array with keys: event, data, target.
-     *
-     * @var array<string, array<string, mixed>>
+     * Each item is an array with keys: event, data, target, componentName.
      */
     private array $eventsToEmit = [];
 
+    /**
+     * Each item is an array with keys: event, payload.
+     */
+    private array $browserEventsToDispatch = [];
+
     public function emit(string $eventName, array $data = [], string $componentName = null): void
     {
         $this->eventsToEmit[] = [
@@ -55,13 +58,27 @@ public function emitSelf(string $eventName, array $data = []): void
         ];
     }
 
+    public function dispatchBrowserEvent(string $event, array $payload = []): void
+    {
+        $this->browserEventsToDispatch[] = [
+            'event' => $event,
+            'payload' => $payload,
+        ];
+    }
+
     public function getEventsToEmit(): array
     {
         return $this->eventsToEmit;
     }
 
+    public function getBrowserEventsToDispatch(): array
+    {
+        return $this->browserEventsToDispatch;
+    }
+
     public function reset(): void
     {
         $this->eventsToEmit = [];
+        $this->browserEventsToDispatch = [];
     }
 }

src/LiveComponent/src/Util/LiveAttributesCollection.php

@@ -92,6 +92,11 @@ public function setEventsToEmit(array $events): void
         $this->attributes['data-live-emit'] = $events;
     }
 
+    public function setBrowserEventsToDispatch(array $browserEventsToDispatch): void
+    {
+        $this->attributes['data-live-browser-dispatch'] = $browserEventsToDispatch;
+    }
+
     private function escapeAttribute(string $value): string
     {
         return twig_escape_filter($this->twig, $value, 'html_attr');

src/LiveComponent/src/Util/LiveControllerAttributesCreator.php

@@ -68,10 +68,15 @@ public function attributesForRendering(MountedComponent $mounted, ComponentMetad
         }
 
         $eventsToEmit = $this->liveResponder->getEventsToEmit();
+        $browserEventsToDispatch = $this->liveResponder->getBrowserEventsToDispatch();
+
         $this->liveResponder->reset();
         if ($eventsToEmit) {
             $attributesCollection->setEventsToEmit($eventsToEmit);
         }
+        if ($browserEventsToDispatch) {
+            $attributesCollection->setBrowserEventsToDispatch($browserEventsToDispatch);
+        }
 
         $mountedAttributes = $mounted->getAttributes();
 

src/LiveComponent/tests/Fixtures/Component/ComponentWithEmit.php

@@ -14,15 +14,15 @@
 use Symfony\UX\LiveComponent\Attribute\AsLiveComponent;
 use Symfony\UX\LiveComponent\Attribute\LiveAction;
 use Symfony\UX\LiveComponent\Attribute\LiveProp;
-use Symfony\UX\LiveComponent\ComponentEmitsTrait;
+use Symfony\UX\LiveComponent\ComponentToolsTrait;
 use Symfony\UX\LiveComponent\DefaultActionTrait;
 use Symfony\UX\LiveComponent\Tests\Fixtures\Entity\Entity1;
 
 #[AsLiveComponent('component_with_emit', csrf: false)]
 final class ComponentWithEmit
 {
     use DefaultActionTrait;
-    use ComponentEmitsTrait;
+    use ComponentToolsTrait;
 
     public $events = [];
 
@@ -32,4 +32,13 @@ public function actionThatEmits(): void
         $this->emit('event1', ['foo' => 'bar']);
         $this->events = $this->liveResponder->getEventsToEmit();
     }
+
+    #[LiveAction]
+    public function actionThatDispatchesABrowserEvent(): void
+    {
+        $this->liveResponder->dispatchBrowserEvent(
+            'browser-event',
+            ['fooKey' => 'barVal'],
+        );
+    }
 }