node:events: EventEmitter import shape and emitter semantics parity tail

[andrewtdiz]

Current scan reports on 2026-06-04 show a focused node:events tail still failing:

• node-suite/events/imports/default-import
• node-suite/events/imports/named-imports
• node-suite/events/emitter/emit-multiple-args
• node-suite/events/emitter/event-names-symbols
• node-suite/events/emitter/instanceof
• node-suite/events/emitter/capture-rejections

Expected Node behavior for this cut:

• the default import is constructible as EventEmitter
• named exports expose EventEmitter, getEventListeners, getMaxListeners, setMaxListeners, and listenerCount
• new EventEmitter() instances satisfy instanceof EventEmitter
• emit(event, ...args) forwards all args to listeners and to events.once() promise resolution
• symbol event names are preserved for eventNames() and listenerCount()
• { captureRejections: true } routes async listener rejection to the error event

Non-goals for this issue:

• domain error routing from native EventEmitter, covered by fix(node): route domain errors from native EventEmitter #4402
• stream close lifecycle, covered by [codex] honor stream close lifecycle options #4386
• child_process stream-backed stdio, covered by fix(child_process): support stream-backed stdio #4401

[andrewtdiz]

I’m taking this as a focused node:events cut.

Scope:

• default/named node:events export shape for EventEmitter and helper functions
• EventEmitter prototype/constructor identity sufficient for instanceof
• variadic emit() delivery, including events.once() resolution arrays
• symbol event-name storage for eventNames() / listenerCount()
• captureRejections for async listener rejections on EventEmitter instances

Non-goals:

• domain error routing from native EventEmitter (fix(node): route domain errors from native EventEmitter #4402)
• stream close lifecycle ([codex] honor stream close lifecycle options #4386)
• child_process stdio/EventEmitter integration (fix(child_process): support stream-backed stdio #4401)

[andrewtdiz]

Checked this against current origin/main (2d9ec1b3f) in a fresh worktree. The fixtures listed here are now passing for me:

• ./run_parity_tests.sh --suite node-suite --module events --filter imports -> 3 pass / 0 fail
• ./run_parity_tests.sh --suite node-suite --module events --filter emitter -> 11 pass / 0 fail

No PR from me for this issue since the gap appears stale/covered by recent events work.

[andrewtdiz]

Opened PR #4424 for this cut: #4424

Covered in this PR:

• node:events EventEmitter import/export shape and constructor identity for instanceof
• variadic emit() delivery and events.once() args-array resolution
• symbol/coerced event-name handling for listener storage and lookup
• captureRejections listener promise rejection routing to error

Non-goals remain the previously scoped areas: native EventEmitter domain routing (#4402), stream close lifecycle (#4386), and child_process stdio/EventEmitter integration (#4401).