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https://github.com/fraunhoferfokus/JSum
Consistent checksum calculation of JSON objects.
https://github.com/fraunhoferfokus/JSum
checksum hash json-objects
Last synced: 3 months ago
JSON representation
Consistent checksum calculation of JSON objects.
- Host: GitHub
- URL: https://github.com/fraunhoferfokus/JSum
- Owner: fraunhoferfokus
- License: agpl-3.0
- Created: 2017-01-23T10:00:04.000Z (almost 8 years ago)
- Default Branch: master
- Last Pushed: 2022-02-15T09:55:13.000Z (almost 3 years ago)
- Last Synced: 2024-05-16T13:02:12.856Z (6 months ago)
- Topics: checksum, hash, json-objects
- Language: JavaScript
- Homepage:
- Size: 105 KB
- Stars: 86
- Watchers: 9
- Forks: 8
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# JSum
Consistent checksum calculation of JSON objects.
[](https://github.com/fraunhoferfokus/JSum/actions/workflows/node.js.yml)
## Quick start
```js
const JSum = require('jsum')
const obj1 = {foo: [{c: 1}, {d: 2, e: 3}], bar: {a: 2, b: undefined}}
const obj2 = {bar: {b: undefined, a: 2}, foo: [{c: 1}, {e: 3, d: 2}]}
console.log(JSum.digest(obj1, 'SHA256', 'hex')) // 9a08ad6302b1e9e5682c365c8b24c5ca2ea6db5c90b672bc5b579879136dda0c
console.log(JSum.digest(obj2, 'SHA256', 'hex')) // 9a08ad6302b1e9e5682c365c8b24c5ca2ea6db5c90b672bc5b579879136dda0c
```
## Why this module?
My main goal was to create [`Etag`s](https://tools.ietf.org/html/rfc7232#section-2.3) from JSON objects. The most intuitive approach
would have been something like:
```js
const crypto = require('crypto')
function checksum (obj) {
return crypto.createHash('MD5').update(JSON.stringify(myObj)).digest('hex')
}
```
However, this approach would yield two different results for semantically same JSON objects:
```js
console.log(checksum({"a": 1, "b": 2})) // 608de49a4600dbb5b173492759792e4a
console.log(checksum({"b": 2, "a": 1})) // 9915965eb40d343a8fe26e4e341d1a05
```
`JSum` on other hand makes sure that semantically same JSON objects always get the same checksum! Moreover, it provides a good deal
of time advantage over some other viable modules\*:
| Module | Time (ms) to hash a 181 MB JSON file (from memory) |
|-------------------------|:---------------------------------------------------:|
| `json-hash` | `81537` |
| `json-stable-stringify` | `12134` |
| `JSum` | `7200` |
| `json-checksum` | `FATAL ERROR: [...] - process out of memory` |
For this trivial test a huge [random JSON file](https://github.com/zemirco/sf-city-lots-json)
(181 MB) was taken as the base for benchmarking. The listed modules were used to create `SHA256` hash of that file. To measure the time,
internal `console.time(()` and `console.timeEnd()` methods were used. Serious benchmarking is described below.
## Benchmarking
You can also run benchmarks to compare performance with similar modules:
```bash
npm i --no-save \
benchmarked \
fast-json-stable-stringify \
json-checksum json-hash \
json-stable-stringify
node benchmark/index.js
```
Results:
```
# benchmark/fixtures/medium.json (77986 bytes)
fast-json-stable-stringify x 1,191 ops/sec ±1.11% (89 runs sampled)
json-checksum x 406 ops/sec ±2.04% (89 runs sampled)
json-hash x 148 ops/sec ±2.08% (75 runs sampled)
json-stable-stringify x 1,051 ops/sec ±2.29% (88 runs sampled)
jsum x 1,339 ops/sec ±0.77% (93 runs sampled)
fastest is jsum
# benchmark/fixtures/small.json (456 bytes)
fast-json-stable-stringify x 116,709 ops/sec ±2.25% (91 runs sampled)
json-checksum x 36,311 ops/sec ±1.66% (91 runs sampled)
json-hash x 12,051 ops/sec ±3.62% (77 runs sampled)
json-stable-stringify x 91,078 ops/sec ±2.08% (89 runs sampled)
jsum x 116,130 ops/sec ±1.46% (90 runs sampled)
fastest is jsum
```