Promise.withResolvers 怎麼用？把一次性事件轉成可取消的等待

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import assert from 'node:assert/strict';
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import { getEventListeners } from 'node:events';
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function waitForEvent(target, type, signal) {
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  if (signal.aborted) return Promise.reject(signal.reason);
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  const { promise, resolve, reject } = Promise.withResolvers();
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  function cleanup() {
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    target.removeEventListener(type, onEvent);
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    signal.removeEventListener('abort', onAbort);
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  }
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  function onEvent(event) {
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    cleanup();
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    resolve(event);
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  }
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  function onAbort() {
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    cleanup();
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    reject(signal.reason);
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  }
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  target.addEventListener(type, onEvent);
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  signal.addEventListener('abort', onAbort);
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  return promise;
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}
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const target = new EventTarget();
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const completed = new AbortController();
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const waiting = waitForEvent(target, 'ready', completed.signal);
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const first = new Event('ready');
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target.dispatchEvent(first);
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assert.equal(getEventListeners(target, 'ready').length, 0);
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assert.equal(getEventListeners(completed.signal, 'abort').length, 0);
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target.dispatchEvent(new Event('ready'));
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completed.abort();
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assert.equal(await waiting, first);
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const cancelled = new AbortController();
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const reason = new Error('畫面已關閉');
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const pending = waitForEvent(target, 'ready', cancelled.signal);
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cancelled.abort(reason);
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assert.equal(getEventListeners(target, 'ready').length, 0);
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assert.equal(getEventListeners(cancelled.signal, 'abort').length, 0);
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target.dispatchEvent(new Event('ready'));
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await assert.rejects(pending, error => error === reason);
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await assert.rejects(
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  waitForEvent(target, 'ready', cancelled.signal),
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  error => error === reason,
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);
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assert.equal(getEventListeners(target, 'ready').length, 0);
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assert.equal(getEventListeners(cancelled.signal, 'abort').length, 0);
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console.log('事件、取消及已中止訊號檢查通過');