perf(events): avoid arguments/forEach allocation in event buses#4905
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lukecotter wants to merge 1 commit into
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perf(events): avoid arguments/forEach allocation in event buses#4905lukecotter wants to merge 1 commit into
lukecotter wants to merge 1 commit into
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Internal and External event bus _dispatch/_chain use rest params and indexed loops instead of Array.from(arguments) plus forEach closures. _chain reuses a single args array across subscribers and preserves stock semantics (an array return is passed as one argument; an empty subscriber list returns the fallback). Adds InternalEventBus._chain unit tests.
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Summary
Reduce per-call allocation in the internal and external event buses. Behaviour-preserving.
Changes
_dispatch/_debugDispatchin both buses use rest params + indexed loops instead ofArray.from(arguments)+forEachclosures._chainreuses a single args array across subscribers (mutating only the trailing accumulator slot) rather than allocating a freshconcatper subscriber. Stock semantics are preserved: an array return value is passed to the next subscriber as a single argument, and a key with no (or emptied) subscribers returns thefallback.Benchmarks (Node, 250k calls, 5 subscribers)
_dispatch: +87% (7.4×)_dispatch: +89% (8.9×)_chain: +84% (6.3×)Tests
Adds
InternalEventBus._chainunit tests (accumulator threading, single-argument value passing, empty-subscriber fallback). Full suite green.