fix(runtime): support "capture" style events

src/runtime/vdom/set-accessor.ts

@@ -109,11 +109,23 @@ export const setAccessor = (
         // except for the first character, we keep the event name case
         memberName = ln[2] + memberName.slice(3);
       }
-      if (oldValue) {
-        plt.rel(elm, memberName, oldValue, false);
-      }
-      if (newValue) {
-        plt.ael(elm, memberName, newValue, false);
+      if (oldValue || newValue) {
+        // Need to account for "capture" events.
+        // If the event name ends with "Capture", we'll update the name to remove
+        // the "Capture" suffix and make sure the event listener is setup to handle the capture event.
+        let capture = false;
+        if (memberName.endsWith(CAPTURE_EVENT_SUFFIX)) {
+          capture = true;
+          // Make sure we only replace the last instance of "Capture"
+          memberName = memberName.replace(new RegExp(CAPTURE_EVENT_SUFFIX + '$'), '');
+        }
+
+        if (oldValue) {
+          plt.rel(elm, memberName, oldValue, capture);
+        }
+        if (newValue) {
+          plt.ael(elm, memberName, newValue, capture);
+        }
       }
     } else if (BUILD.vdomPropOrAttr) {
       // Set property if it exists and it's not a SVG
@@ -170,3 +182,4 @@ export const setAccessor = (
 };
 const parseClassListRegex = /\s/;
 const parseClassList = (value: string | undefined | null): string[] => (!value ? [] : value.split(parseClassListRegex));
+const CAPTURE_EVENT_SUFFIX = 'Capture';

src/runtime/vdom/test/set-accessor.spec.ts

@@ -113,6 +113,36 @@ describe('setAccessor for custom elements', () => {
       expect(addEventSpy).toHaveBeenCalledWith('click', newValue, false);
       expect(removeEventSpy).not.toHaveBeenCalled();
     });
+
+    it('should add a capture style event listener', () => {
+      const addEventSpy = jest.spyOn(elm, 'addEventListener');
+      const removeEventSpy = jest.spyOn(elm, 'removeEventListener');
+
+      const newValue = () => {
+        /**/
+      };
+
+      setAccessor(elm, 'onClickCapture', undefined, newValue, false, 0);
+
+      expect(addEventSpy).toHaveBeenCalledWith('click', newValue, true);
+      expect(removeEventSpy).not.toHaveBeenCalled();
+    });
+
+    it('should remove a capture style event listener', () => {
+      const addEventSpy = jest.spyOn(elm, 'addEventListener');
+      const removeEventSpy = jest.spyOn(elm, 'removeEventListener');
+
+      const orgValue = () => {
+        /**/
+      };
+
+      setAccessor(elm, 'onClickCapture', undefined, orgValue, false, 0);
+      setAccessor(elm, 'onClickCapture', orgValue, undefined, false, 0);
+
+      expect(addEventSpy).toHaveBeenCalledTimes(1);
+      expect(addEventSpy).toHaveBeenCalledWith('click', orgValue, true);
+      expect(removeEventSpy).toHaveBeenCalledWith('click', orgValue, true);
+    });
   });
 
   it('should set object property to child', () => {

test/karma/test-app/components.d.ts

@@ -131,6 +131,8 @@ export namespace Components {
     }
     interface EventCustomType {
     }
+    interface EventListenerCapture {
+    }
     interface ExternalImportA {
     }
     interface ExternalImportB {
@@ -676,6 +678,12 @@ declare global {
         prototype: HTMLEventCustomTypeElement;
         new (): HTMLEventCustomTypeElement;
     };
+    interface HTMLEventListenerCaptureElement extends Components.EventListenerCapture, HTMLStencilElement {
+    }
+    var HTMLEventListenerCaptureElement: {
+        prototype: HTMLEventListenerCaptureElement;
+        new (): HTMLEventListenerCaptureElement;
+    };
     interface HTMLExternalImportAElement extends Components.ExternalImportA, HTMLStencilElement {
     }
     var HTMLExternalImportAElement: {
@@ -1355,6 +1363,7 @@ declare global {
         "esm-import": HTMLEsmImportElement;
         "event-basic": HTMLEventBasicElement;
         "event-custom-type": HTMLEventCustomTypeElement;
+        "event-listener-capture": HTMLEventListenerCaptureElement;
         "external-import-a": HTMLExternalImportAElement;
         "external-import-b": HTMLExternalImportBElement;
         "external-import-c": HTMLExternalImportCElement;
@@ -1575,6 +1584,8 @@ declare namespace LocalJSX {
     interface EventCustomType {
         "onTestEvent"?: (event: EventCustomTypeCustomEvent<TestEventDetail>) => void;
     }
+    interface EventListenerCapture {
+    }
     interface ExternalImportA {
     }
     interface ExternalImportB {
@@ -1856,6 +1867,7 @@ declare namespace LocalJSX {
         "esm-import": EsmImport;
         "event-basic": EventBasic;
         "event-custom-type": EventCustomType;
+        "event-listener-capture": EventListenerCapture;
         "external-import-a": ExternalImportA;
         "external-import-b": ExternalImportB;
         "external-import-c": ExternalImportC;
@@ -2002,6 +2014,7 @@ declare module "@stencil/core" {
             "esm-import": LocalJSX.EsmImport & JSXBase.HTMLAttributes<HTMLEsmImportElement>;
             "event-basic": LocalJSX.EventBasic & JSXBase.HTMLAttributes<HTMLEventBasicElement>;
             "event-custom-type": LocalJSX.EventCustomType & JSXBase.HTMLAttributes<HTMLEventCustomTypeElement>;
+            "event-listener-capture": LocalJSX.EventListenerCapture & JSXBase.HTMLAttributes<HTMLEventListenerCaptureElement>;
             "external-import-a": LocalJSX.ExternalImportA & JSXBase.HTMLAttributes<HTMLExternalImportAElement>;
             "external-import-b": LocalJSX.ExternalImportB & JSXBase.HTMLAttributes<HTMLExternalImportBElement>;
             "external-import-c": LocalJSX.ExternalImportC & JSXBase.HTMLAttributes<HTMLExternalImportCElement>;

test/karma/test-app/event-listener-capture/cmp.tsx

@@ -0,0 +1,21 @@
+import { Component, h, State } from '@stencil/core';
+
+@Component({
+  tag: 'event-listener-capture',
+})
+export class EventListenerCapture {
+  @State() counter = 0;
+
+  render() {
+    return (
+      <div>
+        <p>Click the text below to trigger a capture style event</p>
+        <div>
+          <p id="incrementer" onClickCapture={() => this.counter++}>
+            Clicked: <span id="counter">{this.counter}</span> time(s)
+          </p>
+        </div>
+      </div>
+    );
+  }
+}

test/karma/test-app/event-listener-capture/index.html

@@ -0,0 +1,6 @@
+<!doctype html>
+<meta charset="utf8" />
+<script src="./build/testapp.esm.js" type="module"></script>
+<script src="./build/testapp.js" nomodule></script>
+
+<event-listener-capture></event-listener-capture>

test/karma/test-app/event-listener-capture/karma.spec.ts

@@ -0,0 +1,31 @@
+import { setupDomTests, waitForChanges } from '../util';
+
+describe('event-listener-capture', function () {
+  const { setupDom, tearDownDom } = setupDomTests(document);
+
+  let app: HTMLElement | undefined;
+  let host: HTMLElement | undefined;
+
+  beforeEach(async () => {
+    app = await setupDom('/event-listener-capture/index.html');
+    host = app.querySelector('event-listener-capture');
+  });
+
+  afterEach(tearDownDom);
+
+  it('should render', () => {
+    expect(host).toBeDefined();
+  });
+
+  it('should increment counter on click', async () => {
+    const counter = host.querySelector('#counter');
+    expect(counter.textContent).toBe('0');
+
+    const p = host.querySelector('#incrementer') as HTMLParagraphElement;
+    expect(p).toBeDefined();
+    p.click();
+    await waitForChanges();
+
+    expect(counter.textContent).toBe('1');
+  });
+});