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setBigTimeout

(evanhahn.com)
210 points cfj | 3 comments | 17 Oct 24 18:01 UTC | HN request time: 0.624s | 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. blixt ◴[18 Oct 24 17:38 UTC] No.41881685[source]▶
JS numbers technically have 53 bits for integers (mantissa) but all binary operators turns it into a 32-bit signed integer. Maybe this is related somehow to the setTimeout limitation. JavaScript also has the >>> unsigned bit shift operator so you can squeeze that last bit out of it if you only care about positive values: ((2*32-1)>>>0).toString(2).length === 32
replies(1): >>41882267 #
2. tubs ◴[18 Oct 24 18:42 UTC] No.41882267[source]▶
I assume by binary you mean logical? A + b certainly does not treat either side as 32bit.
replies(1): >>41882779 #
3. blixt ◴[18 Oct 24 19:41 UTC] No.41882779[source]▶
Sorry, I meant bitwise operators, such as: ~ >> << >>> | &