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lib: fix expensive isNaN call in readable streams #1925

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lib: fix expensive isNaN call in readable streams #1925

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2 changes: 1 addition & 1 deletion lib/_stream_readable.js
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Original file line number Diff line number Diff line change
Expand Up @@ -211,7 +211,7 @@ function howMuchToRead(n, state) {
if (state.objectMode)
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@thefourtheye thefourtheye Jun 9, 2015

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What if state is undefined?

return n === 0 ? 0 : 1;

if (n === null || isNaN(n)) {
if (n === null || n !== n) {
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@thefourtheye thefourtheye Jun 9, 2015

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Might be a little paranoid here and totally not related to this PR, but If n is not a number, then we might fail somewhere with improper error message I guess.

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@Fishrock123 Fishrock123 Jun 9, 2015

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Oh, good point. This may not just be checking it it is NaN, but also non-number values.

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@trevnorris trevnorris Jun 9, 2015

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@bnoordhuis This does change the functionality from isNaN(n) to Number.isNaN(n) (don't we all love JS). The only way I can think to make sure it matches is to change the check to:

if (n === null || (+n) != n) {

// only flow one buffer at a time
if (state.flowing && state.buffer.length)
return state.buffer[0].length;
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