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perf: simple asString #787

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perf: simple asString #787

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439ae64
perf: simple asString
cesco69 Sep 22, 2025
2a2e4e4
fix: isWellFormed
cesco69 Sep 22, 2025
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35 changes: 5 additions & 30 deletions lib/serializer.js
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Original file line number Diff line number Diff line change
@@ -1,5 +1,7 @@
'use strict'

const findEscapeSequence = /["\b\t\n\v\f\r\/]/

Check failure on line 3 in lib/serializer.js

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GitHub Actions / test / quality-check / Lint Code 

Unnecessary escape character: \/

module.exports = class Serializer {
constructor (options) {
switch (options && options.rounding) {
Expand Down Expand Up @@ -88,37 +90,10 @@
}

asString (str) {
const len = str.length
if (len < 42) {
// magically escape strings for json
// relying on their charCodeAt
// everything below 32 needs JSON.stringify()
// every string that contain surrogate needs JSON.stringify()
// 34 and 92 happens all the time, so we
// have a fast case for them
let result = ''
let last = -1
let point = 255
for (let i = 0; i < len; i++) {
point = str.charCodeAt(i)
if (
point === 0x22 || // '"'
point === 0x5c // '\'
) {
last === -1 && (last = 0)
result += str.slice(last, i) + '\\'
last = i
} else if (point < 32 || (point >= 0xD800 && point <= 0xDFFF)) {
// The current character is non-printable characters or a surrogate.
return JSON.stringify(str)
}
}
return (last === -1 && ('"' + str + '"')) || ('"' + result + str.slice(last) + '"')
} else if (len < 5000 && str.isWellFormed()) {
// Only use the regular expression for shorter input. The overhead is otherwise too much.
return '"' + str + '"'
} else {
if (findEscapeSequence.test(str)) {
return JSON.stringify(str)
} else {
return '"' + str + '"'
}
}

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