Hacktoberfest 2026：维护者为十月标记出来的 issue，仍然开放、适合新手。 浏览 Hacktoberfest issue

bug(aria/combobox): keys pressed back to back are lost; only the last one reaches the popup

未关闭 适合新手
  • 哪里不对？
#33,973 0 条评论 0 个 reaction 已指派 0 人 在 GitHub 查看

维护者通常 1 天内回复

@drakeo338 已经在做这个了。

开始于 2026年10月20日。

  • #33975 来自 @drakeo338 —— 未关闭

评估

难度
2/5
预计耗时
1-3 小时
新手友好度
78/100
Issue 类型
缺陷
描述清晰度
描述清楚
活跃度
活跃
技术栈
angular, typescript
领域
accessibility, frontend

调研方向

从 Angular 的 ARIA combobox 实现中的 ComboboxPattern 入手。issue 指出，keyboardEventRelay 在此处被设置，随后重新分发到 popup control target。跟踪按键处理程序和 relay effect，然后为多个连续的 ArrowDown 事件添加或更新单元测试。完成标准是每个事件都按顺序处理，按三次会移动三个选项。

由索引模型根据 Issue 内容生成。

描述

area: aria/combobox gemini-triaged
Is this a regression?
  • Yes, this behavior used to work in the previous version
The previous version in which this bug was not present was

No response

Description

While the popup is open, ComboboxPattern relays navigation and typeahead keys to the popup through a signal: the key handler does this.keyboardEventRelay.set(e), and an effect later re-dispatches the event on the popup's control target. If a second key arrives before the effect runs, the signal is overwritten and the first key is never relayed.

Effects:

  • Down, Down, Down pressed quickly moves the active option once.
  • Typeahead loses characters: with options item, item-2, item-3, typing item-3 with no delay between keys lands on item; with 60 ms between keys it lands on item-3.
  • Test automation and tools that send keys in a burst (and some assistive technology input) see wrong results. Seen in Chromium through Playwright, and in unit tests.

Related: #33361 (same relay signal, different symptom: a stale event replayed on reopen).

Reproduction
import { Component } from '@angular/core';
import { TestBed } from '@angular/core/testing';
import { Combobox, ComboboxPopup, ComboboxWidget } from '@angular/aria/combobox';
import { Listbox, Option } from '@angular/aria/listbox';

@Component({
  imports: [Combobox, ComboboxPopup, ComboboxWidget, Listbox, Option],
  template: `
    <div ngCombobox #combobox="ngCombobox" tabindex="0">Pick one</div>
    <ng-template ngComboboxPopup [combobox]="combobox">
      <div ngListbox ngComboboxWidget #listbox="ngListbox" focusMode="activedescendant"
        [activeDescendant]="listbox.activeDescendant()">
        @for (o of options; track o) {
          <div ngOption [value]="o" [label]="o">{{ o }}</div>
        }
      </div>
    </ng-template>
  `,
})
class Repro {
  options = ['alpha', 'bravo', 'charlie', 'delta'];
}

const key = (el: Element, k: string) =>
  el.dispatchEvent(new KeyboardEvent('keydown', { key: k, bubbles: true }));

it('handles each key pressed back to back', async () => {
  const fixture = TestBed.createComponent(Repro);
  await fixture.whenStable();
  const combobox = fixture.nativeElement.querySelector('[ngCombobox]');
  combobox.focus();
  key(combobox, 'ArrowDown');            // open
  await fixture.whenStable();
  key(combobox, 'Home');
  await fixture.whenStable();
  key(combobox, 'ArrowDown');
  key(combobox, 'ArrowDown');
  key(combobox, 'ArrowDown');
  await fixture.whenStable();
  const id = combobox.getAttribute('aria-activedescendant');
  expect(fixture.nativeElement.querySelector(`[id="${id}"]`).textContent.trim())
    .toBe('delta');                       // actual: 'bravo'
});
Expected Behavior

Each key event is handled, in order. Three Down presses move three options.

Actual Behavior

Only the last key since the effect last ran is relayed. Three Down presses move one option ("bravo" in place of "delta").

A possible fix: relay each event synchronously from the key handler (or queue them), not through a single-value signal.

Environment
  • Angular: 22.2.1
  • CDK/Material: @angular/cdk 22.2.3, @angular/aria 22.2.3 (also in 22.3.0-next.2 and main)
  • Browser(s): Chromium (Playwright); Vitest with happy-dom
  • Operating System (e.g. Windows, macOS, Ubuntu): macOS
主要语言
TypeScript
星标
25k
派生
6.8k
平均合并
1 天 5 小时
30 天内合并 PR
67

环境准备

  • 没有 Dockerfile 或 Docker Compose 文件
  • 没有 Pull Request 模板
  • 阅读贡献指南

从这里开始

  1. 先读完整个 Issue，再读项目的贡献指南。
  2. 在 Issue 下留言说明你要接手 —— 这能避免两个人做同样的事。
  3. Fork 仓库，在一个分支上完成修改。
  4. 提交 Pull Request，并在描述里引用这个 Issue 编号。

angular/components 的其他 Issue

查看 angular/components 的全部 Issue

相似的 Issue

更多 TypeScript Issue

把新 issue 发到你的邮箱

精选适合新手参与的 GitHub issue 摘要。