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setBigTimeout

(evanhahn.com)
210 points cfj | 1 comments | 17 Oct 24 18:01 UTC | HN request time: 0.256s | source
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yesco ◴[18 Oct 24 17:04 UTC] No.41881325[source]▶
> In most JavaScript runtimes, this duration is represented as a 32-bit signed integer

I thought all numbers in JavaScript were basically some variation of double precision floating points, if so, why is setTimeout limited to a smaller 32bit signed integer?

If this is true, then if I pass something like "0.5", does it round the number when casting it to an integer? Or does it execute the callback after half a millisecond like you would expect it would?

replies(3): >>41881670 #>>41881685 #>>41884172 #
1. DvdGiessen ◴[18 Oct 24 22:45 UTC] No.41884172[source]▶
When implementing a tiny timing library in JS a few years back I found that most engines indeed seem to cast the value to an integer (effectively flooring it), so in order to get consistent behaviour in all environments I resorted to always calling Math.ceil on the timeout value first [1], thus making it so that the callbacks always fire after at least the given timeout has passed (same as with regular setTimeout, which also cannot guarantee that the engine can run the callback at exactly the given timeout due to scheduling). Also used a very similar timeout chaining technique as described here, it works well!

[1]: https://github.com/DvdGiessen/virtual-clock/blob/master/src/...