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feat: improved bytesToUuid func #434

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merged 3 commits into from May 4, 2020
Merged

feat: improved bytesToUuid func #434

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2136152
feat: improved bytesToUuid func
awwit May 3, 2020
149adf7
style: added comment to bytesToUuid func
awwit May 4, 2020
a660ec5
style: remove one line of comment
awwit May 4, 2020
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7 changes: 6 additions & 1 deletion examples/benchmark/benchmark.js
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Expand Up @@ -9,7 +9,12 @@ const uuidv5 = (typeof window !== 'undefined' && window.uuidv5) || require('uuid
console.log('Starting. Tests take ~1 minute to run ...');

const array = new Array(16);
const suite = new Benchmark.Suite();

const suite = new Benchmark.Suite({
onError(event) {
console.error(event.target.error);
},
});

suite
.add('uuidv1()', function () {
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44 changes: 22 additions & 22 deletions src/bytesToUuid.js
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Expand Up @@ -14,28 +14,28 @@ function bytesToUuid(buf, offset) {
const bth = byteToHex;

// join used to fix memory issue caused by concatenation: https://bugs.chromium.org/p/v8/issues/detail?id=3175#c4
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The issue linked above is still unresolved.

@awwit have you tried the examples in that issue in recent Node.js or Chrome versions to see if the issue still exists?

@broofa can you shed some light on this? I saw the discussion in #267 but cannot judge if this is still an issue?

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Oh, I just saw #267 (comment) which I must have missed while reading the other issue initially.

Seems like .toLowerCase() is also a workaround for the memory issue? If this turns out to be true (@broofa / @sava-smith can you confirm) then we should at least update the comment here to reflect the new hack?

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@ctavan I tried different ways to fix this bug. It still exists in the V8 engine. (Did not check for other engines).

The fastest option was ".toLowerCase()" on V8 engine. It also forms a normal-sized string like .join('').

There is still a compromise option (' ' + str).slice(1) which works even faster, but consumes a little more memory for the result string.

return [
bth[buf[i + 0]],
bth[buf[i + 1]],
bth[buf[i + 2]],
bth[buf[i + 3]],
'-',
bth[buf[i + 4]],
bth[buf[i + 5]],
'-',
bth[buf[i + 6]],
bth[buf[i + 7]],
'-',
bth[buf[i + 8]],
bth[buf[i + 9]],
'-',
bth[buf[i + 10]],
bth[buf[i + 11]],
bth[buf[i + 12]],
bth[buf[i + 13]],
bth[buf[i + 14]],
bth[buf[i + 15]],
].join('');
return (
bth[buf[i + 0]] +
bth[buf[i + 1]] +
bth[buf[i + 2]] +
bth[buf[i + 3]] +
'-' +
bth[buf[i + 4]] +
bth[buf[i + 5]] +
'-' +
bth[buf[i + 6]] +
bth[buf[i + 7]] +
'-' +
bth[buf[i + 8]] +
bth[buf[i + 9]] +
'-' +
bth[buf[i + 10]] +
bth[buf[i + 11]] +
bth[buf[i + 12]] +
bth[buf[i + 13]] +
bth[buf[i + 14]] +
bth[buf[i + 15]]
).toLowerCase();
}

export default bytesToUuid;