doc: clarify setTimeout millisecond precision behavior#62468
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vijaygovindaraja wants to merge 1 commit intonodejs:mainfrom
Open
doc: clarify setTimeout millisecond precision behavior#62468vijaygovindaraja wants to merge 1 commit intonodejs:mainfrom
vijaygovindaraja wants to merge 1 commit intonodejs:mainfrom
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Document that timer delays are tracked with millisecond precision internally, and that callbacks may appear to fire up to 1ms early when measured with sub-millisecond clocks (process.hrtime(), performance.now()). This is caused by rounding at the millisecond boundary and is most noticeable when timers interact with setImmediate() or other I/O. Refs: nodejs#26578 Signed-off-by: V Govindarajan <vijay.govindarajan91@gmail.com>
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Timer delays are tracked with millisecond precision internally. When
measured with sub-millisecond clocks (
process.hrtime(),performance.now()), callbacks may appear to fire up to 1ms earlydue to rounding at the millisecond boundary.
This has been a source of confusion for 7+ years (see #26578). Rather
than changing the timer implementation, this documents the existing
behavior so users understand the precision guarantee.
Approach discussed and endorsed by @apapirovski in #62466.
Refs: #26578