re: What is the oddest JavaScript behavior? VIEW POST


A colleague the other day noticed that the setTimeout/setInterval takes a 32 bit signed int as an argument, which is fine except that (as far as I know) JS doesn't natively support integers... but but instead Numbers are specifically 8 byte signed doubles. If you happen to have a interval or timeout every 2^31 miliseconds (ish) or more, then the value is interpreted as a negative number and therefore executes instantly and in terms of intervals repeatedly. So timeouts and intervals are limited to just under 25 days.


I'm guessing a web app won't need a 25-day timeout or interval.

I tried a very basic test on node and it seems to be waiting on it to execute... any idea why?


not sure... i just ran it in node and experienced the same issue as the browser. The following line should make node print without pausing:

setInterval(() => {console.log('log')}, 2**31)


setInterval(() => {console.log('log')}, -1)

where the following will take 596.5 hours (roughly):

setInterval(() => {console.log('log')}, 2**31-1)

I am currently on a Windows machine running v8.9.1, perhaps its solved in later versions?

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