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fixes #169: throw a RangeError in take/drop when input is NaN-ish #181

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merged 1 commit into from Jul 5, 2022
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fixes #169: throw a RangeError in take/drop when input is NaN-ish #181

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8 changes: 6 additions & 2 deletions spec.html
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Expand Up @@ -533,7 +533,9 @@ <h1>%Iterator.prototype%.filter ( _filterer_ )</h1>
<h1>%Iterator.prototype%.take ( _limit_ )</h1>
<emu-alg>
1. Let _iterated_ be ? GetIteratorDirect(*this* value).
1. Let _integerLimit_ be ? ToIntegerOrInfinity(_limit_).
1. Let _numLimit_ be ? ToNumber(_limit_).
1. If _numLimit_ is *NaN*, throw a *RangeError* exception.
1. Let _integerLimit_ be ! ToIntegerOrInfinity(_numLimit_).
1. If _integerLimit_ &lt; 0, throw a *RangeError* exception.
1. Let _closure_ be a new Abstract Closure with no parameters that captures _iterated_ and _integerLimit_ and performs the following steps when called:
1. Let _remaining_ be _integerLimit_.
Expand All @@ -555,7 +557,9 @@ <h1>%Iterator.prototype%.take ( _limit_ )</h1>
<h1>%Iterator.prototype%.drop ( _limit_ )</h1>
<emu-alg>
1. Let _iterated_ be ? GetIteratorDirect(*this* value).
1. Let _integerLimit_ be ? ToIntegerOrInfinity(_limit_).
1. Let _numLimit_ be ? ToNumber(_limit_).
1. If _numLimit_ is *NaN*, throw a *RangeError* exception.
1. Let _integerLimit_ be ! ToIntegerOrInfinity(_numLimit_).
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What if integerLimit is not in the safe integer range?

For example, in the case of Number.MAX_SAFE_INTEGER + 2 it will never take a value.

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This iteration happens on mathematical values, not floats, so the max safe integer for floats doesn't come into play at all here.

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Reasonable. It seems necessary to think about what should be used in polyfills for such cases.

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@bakkot bakkot Jul 6, 2022 •
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You could use a BigInt, but honestly, your computer is going to run out of time/memory before it runs into this problem.

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Iterator helper is one of the solutions for preventing out of memory in such cases and 2**53 is not such a big value that it can't happen for some years of a server work -) BigInt directly will not work for old env. However, I agree that there are many more priority tasks.

1. If _integerLimit_ &lt; 0, throw a *RangeError* exception.
1. Let _closure_ be a new Abstract Closure with no parameters that captures _iterated_ and _integerLimit_ and performs the following steps when called:
1. Let _remaining_ be _integerLimit_.
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