[Refactor] Handle pathological strings better #6
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Improve input string that are pathological by virtue of containing lots of whitespace but not at the end of the string. Such strings can lead to quadratic runtime of the `endWhitespace` regular expression, unnecessarily consuming computational resources. This patches addresses the problem by ensuring that the string does end with a whitespace character before removing whitespace character from the end of the string. This ensures that pathological inputs cannot cause quadratic runtime because such inputs won't reach the `endWhitespace` expression. An alternative solution would be to have a negative lookbehind in the `endWhitespace` expression. But, this regexp feature was not yet available in versions of JavaScript for which this polyfill is meant, hence it is not viable.
ericcornelissen
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If there's no regression test I'm not sure it's worth fixing. |
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Improve input string that are pathological by virtue of containing lots of whitespace but not at the end of the string. Such strings can lead to quadratic runtime of the
endWhitespaceregular expression, unnecessarily consuming computational resources.This patches addresses the problem by ensuring that the string does end with a whitespace character before removing whitespace character from the end of the string. This ensures that pathological inputs cannot cause quadratic runtime because such inputs won't reach the
endWhitespaceexpression.An alternative solution would be to have a negative lookbehind in the
endWhitespaceexpression. But, this regexp feature was not yet available in versions of JavaScript for which this polyfill is meant, hence it is not viable.(the change to the test is just a minor, unrelated correction)