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Calculate string size in a browser precisely. #83

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1aded8c
Calculate string size in a browser precisely. Fixes https://github.co…
miktam Feb 7, 2023
e1cdc92
Merged the master
miktam Feb 11, 2023
f912efb
Use new Buffer.from().byteLength for node. Special case for an empty …
miktam Feb 11, 2023
4d7efa5
Add long string for browser test
miktam Feb 11, 2023
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8 changes: 5 additions & 3 deletions indexv2.js
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Original file line number Diff line number Diff line change
Expand Up @@ -6,11 +6,13 @@ const Buffer = require('buffer/').Buffer

/**
* Precisely calculate size of string in node
* Based on https://stackoverflow.com/questions/68789144/how-much-memory-do-v8-take-to-store-a-string/68791382#68791382
* @param {} str
*/
function preciseStringSizeNode (str) {
return 12 + 4 * Math.ceil(str.length / 4)
if (str === '') {
return 4
}
return new Buffer.from(str).byteLength
}

/**
Expand Down Expand Up @@ -88,7 +90,7 @@ function objectSizeSimple (obj) {
if (isNodeEnvironment()) {
bytes += preciseStringSizeNode(value)
} else {
bytes += value.length * ECMA_SIZES.STRING
bytes += new TextEncoder().encode(value).length
}
} else if (typeof value === 'number') {
bytes += ECMA_SIZES.NUMBER
Expand Down
90 changes: 3 additions & 87 deletions package-lock.json
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2 changes: 1 addition & 1 deletion package.json
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
{
"name": "object-sizeof",
"version": "2.6.1",
"version": "2.7.0",
"description": "Sizeof of a JavaScript object in Bytes",
"main": "indexv2.js",
"scripts": {
Expand Down
24 changes: 19 additions & 5 deletions test/test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,10 @@
/* global describe, it */

const should = require('should')
const v8 = require('v8')
const sizeof = require('../indexv2.js')
const LONG_STRING =
'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed ac vestibulum lacus, sit amet maximus libero. Aliquam erat volutpat. Quisque at orci tortor. Donec at mi nunc.'

describe('sizeof node.js tests', () => {
it('should handle null in object keys', () => {
Expand All @@ -23,12 +26,19 @@ describe('sizeof node.js tests', () => {
sizeof().should.be.equal(0)
})

it('of 3 chars string is 16 in node.js', () => {
sizeof('abc').should.be.equal(16)
it('of 3 chars string is 3 bytes in node.js', () => {
const abcString = 'abc'
sizeof(abcString).should.be.equal(3)
})

it('sizeof of empty string', () => {
sizeof('').should.be.equal(12)
const emptyString = ''
sizeof(emptyString).should.be.equal(v8.serialize(emptyString).byteLength)
sizeof(emptyString).should.be.equal(4)
})

it('sizeof of a long string', () => {
sizeof(LONG_STRING).should.be.equal(171)
})

it('boolean size shall be 4', () => {
Expand Down Expand Up @@ -143,8 +153,12 @@ describe('sizeof browser tests', () => {
global.document = {}
})

it('each caracter is two bytes in a browser environent', () => {
sizeof('abc').should.be.equal(6)
it('in a browser environent string', () => {
sizeof('abc').should.be.equal(3)
})

it('sizeof of a long string', () => {
sizeof(LONG_STRING).should.be.equal(171)
})

afterEach(function () {
Expand Down