fix: return the running execution's signal from getAbortSignal() in AsyncDebouncer and AsyncThrottler

[SimenB]

🎯 Changes

getAbortSignal() returns null inside the executing function in two cases, so the getAbortSignal JSDoc example, which only calls fetch inside if (signal), skips its request:

Case	Cause	Fix
AsyncDebouncer, any execution	#execute stores each execution's retryer under maybeExecuteCount + 1, and getAbortSignal() looks it up under maybeExecuteCount.	#execute uses maybeExecuteCount as the key, the same key AsyncThrottler uses.
AsyncDebouncer and AsyncThrottler, a newer call arrives but has not started yet	With no argument, getAbortSignal() looks up the newest call's count, which has no retryer yet.	With no argument, return the signal of the most recently started execution that is still running, as its JSDoc describes. An explicit maybeExecuteCount still looks up that execution.

If the newer call's execution has already started, getAbortSignal() with no argument returns that newer signal. Read the signal before the first await, as the JSDoc example does.

Fixes #186 and closes #187, which has the same key fix as the first row above.

✅ Checklist

• I have followed the steps in the Contributing guide.
• I have tested this code locally with pnpm run test:pr.

🚀 Release Impact

• This change affects published code, and I have generated a changeset.
• This change is docs/CI/dev-only (no release).

Summary by CodeRabbit

• Bug Fixes

  • Fixed getAbortSignal() for async debounced and throttled executions so it returns the active execution’s abort signal instead of null.
  • Preserved the correct signal while newer executions begin waiting or overlapping executions are in progress.
  • Improved signal selection for the latest active execution.

• Tests

  • Added coverage for overlapping debounced executions and throttled executions that remain active while subsequent calls begin.

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• .changeset/quiet-foxes-listen.md
• packages/pacer/src/async-debouncer.ts
• packages/pacer/src/async-throttler.ts
• packages/pacer/tests/async-debouncer.test.ts
• packages/pacer/tests/async-throttler.test.ts

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📝 Walkthrough

Walkthrough

The async debouncer and async throttler now use the most recently inserted retryer when getAbortSignal() is called without an execution count. Tests cover overlapping executions in both classes.

Changes

Async abort signals

Layer / File(s)	Summary
Latest retryer lookup and overlap tests packages/pacer/src/async-debouncer.ts, packages/pacer/src/async-throttler.ts, packages/pacer/tests/async-debouncer.test.ts, packages/pacer/tests/async-throttler.test.ts, .changeset/quiet-foxes-listen.md	Both classes use the latest retryer for default getAbortSignal() lookups. Explicit-count lookups remain unchanged. Tests check signal identity during overlapping executions. The changeset declares a patch release.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: kevinvandy

Merge Risk: ⚪ Minimal · up to f09cd

The abort-signal lookup change is mergeable after normal checks. A pre-existing overlap limitation remains, but this change does not worsen it.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 4…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely identifies the change to getAbortSignal() in both AsyncDebouncer and AsyncThrottler.
Description check	✅ Passed	The description includes the required Changes, Checklist, and Release Impact sections. It explains the behavior and motivation, marks the relevant checklist items, and reports testing and a changeset.

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Actionable comments posted: 1

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Inline comments:
In `@packages/pacer/src/async-debouncer.ts`:
- Line 366: Update the default retryer lookup in `getAbortSignal` to return the
most recently inserted active retryer when no `maybeExecuteCount` is provided;
keep explicit-count lookups unchanged. Add a test covering overlapping execution
where `maybeExecute()` advances the count while an earlier execution remains
active.

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