events: allow an event to be dispatched multiple times

[lpinca]

Use a different flag to prevent recursive dispatching.

[lpinca]

@aduh95 PTAL.

[aduh95]

Unrelated to this PR: Chromium and Safari both return an empty array when dispatching an event. Firefox has the same behavior as Node.js. I couldn't find which behavior is spec compliant.

{
  // Same event dispatched multiple times.
  const event = new Event('foo');
  const eventTarget1 = new EventTarget();
  const eventTarget2 = new EventTarget();

  eventTarget1.addEventListener('foo', ((event) => {
    console.log(event.target===eventTarget1, event.eventPhase===Event.AT_TARGET); // true true
    const path = event.composedPath();
    console.log(path.length === 1, path[0]===eventTarget1); // depends on the browser:
    // On Firefox + Node.js: true true
    // On Safari + Chromium : false false
  }));

  eventTarget2.addEventListener('foo', ((event) => {
    console.log(event.target===eventTarget2, event.eventPhase===Event.AT_TARGET); // true true
    const path = event.composedPath();
    console.log(path.length === 1, path[0]===eventTarget2); // depends on the browser
  }));

  eventTarget1.dispatchEvent(event);
  console.log(event.target===eventTarget1, event.eventPhase===Event.NONE); // true true
  console.log(event.composedPath().length === 0); // true

  eventTarget2.dispatchEvent(event);
  console.log(event.target===eventTarget2, event.eventPhase===Event.NONE); // true true
  console.log(event.composedPath().length === 0); // true
}

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/39199/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/39207/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/39255/

[lpinca]

Landed in 5c4e673.