Allowing Date.now() return fractional as well as integral bits (for submillisecond timing)

Paul Biggar pbiggar at mozilla.com
Fri Aug 6 13:27:34 PDT 2010


Hi,

In SpiderMonkey, we can very easily make Date.now() return fractional
bits, which allows sub-millisecond timing. I've been using this for a
few weeks, and it's been very useful for my small purposes (more
accurate benchmarks). We're now looking at making this a feature of
Date.now().

According to Brendan's reading of the standard, this is allowed,
partially due to Date.now() being underspecified. The question is
whether this is a good idea, or if we should shelve it pending the
nanoAge proposal, or propose a
Date.nowWithFractionalBitsAndABetterName() instead?

The Mozilla bug is here: https://bugzilla.mozilla.org/show_bug.cgi?id=585152

Comments appreciated.

Thanks,
Paul

-- 
Paul Biggar
Javascript core engineer
pbiggar at mozilla.com


More information about the es-discuss mailing list