File: /home/ploi/drdrive.lightweb.kr/node_modules/stable-hash-x/README.md
# stable-hash-x
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A tiny and fast (600B <sup>[unpkg](https://unpkg.com/stable-hash-x@latest/lib/index.js)</sup>) lib for "stably hashing" a JavaScript value, works with cross-realm objects. Originally created for [SWR](https://github.com/vercel/swr) by [Shu Ding][] at [`stable-hash`](https://github.com/shuding/stable-hash), we forked it because the original one is a bit out of maintenance for a long time.
It's similar to `JSON.stringify(value)`, but:
1. Supports any JavaScript value (`BigInt`, `NaN`, `Symbol`, `function`, `class`, ...)
2. Sorts object keys (stable)
3. Supports circular objects
## TOC <!-- omit in toc -->
- [Use](#use)
- [Examples](#examples)
- [Primitive Value](#primitive-value)
- [Regex](#regex)
- [Date](#date)
- [Array](#array)
- [Object](#object)
- [`Function`, `Class`, `Set`, `Map`, `Buffer`...](#function-class-set-map-buffer)
- [Cross-realm](#cross-realm)
- [Benchmark](#benchmark)
- [Notes](#notes)
- [Sponsors and Backers](#sponsors-and-backers)
- [Sponsors](#sponsors)
- [Backers](#backers)
- [Changelog](#changelog)
- [License](#license)
## Use
```bash
yarn add stable-hash-x
```
```js
import { hash } from 'stable-hash-x'
hash(anyJavaScriptValueHere) // returns a string
hash(anyJavaScriptValueHere, true) // if you're running in cross-realm environment, it's disabled by default for performance
```
## Examples
### Primitive Value
```js
hash(1)
hash('foo')
hash(true)
hash(undefined)
hash(null)
hash(NaN)
```
BigInt:
```js
hash(1) === hash(1n)
hash(1) !== hash(2n)
```
Symbol:
```js
hash(Symbol.for('foo')) === hash(Symbol.for('foo'))
hash(Symbol.for('foo')) === hash(Symbol('foo'))
hash(Symbol('foo')) === hash(Symbol('foo'))
hash(Symbol('foo')) !== hash(Symbol('bar'))
```
_Since `Symbol`s cannot be serialized, `stable-hash-x` simply uses its description as the hash._
### Regex
```js
hash(/foo/) === hash(/foo/)
hash(/foo/) !== hash(/bar/)
```
### Date
```js
hash(new Date(1)) === hash(new Date(1))
```
### Array
```js
hash([1, '2', [new Date(3)]]) === hash([1, '2', [new Date(3)]])
hash([1, 2]) !== hash([2, 1])
```
Circular:
```js
const foo = []
foo.push(foo)
hash(foo) === hash(foo)
```
### Object
```js
hash({ foo: 'bar' }) === hash({ foo: 'bar' })
hash({ foo: { bar: 1 } }) === hash({ foo: { bar: 1 } })
```
Stable:
```js
hash({ a: 1, b: 2, c: 3 }) === hash({ c: 3, b: 2, a: 1 })
```
Circular:
```js
const foo = {}
foo.foo = foo
hash(foo) === hash(foo)
```
### `Function`, `Class`, `Set`, `Map`, `Buffer`...
`stable-hash-x` guarantees reference consistency (`===`) for objects that the constructor isn't `Object`.
```js
const foo = () => {}
hash(foo) === hash(foo)
hash(foo) !== hash(() => {})
```
```js
class Foo {}
hash(Foo) === hash(Foo)
hash(Foo) !== hash(class {})
```
```js
const foo = new Set([1])
hash(foo) === hash(foo)
hash(foo) !== hash(new Set([1]))
```
### Cross-realm
```js
import { runInNewContext } from 'node:vm'
const obj1 = {
a: 1,
b: new Date('2022-06-25T01:55:27.743Z'),
c: /test/,
f: Symbol('test'),
}
const obj2 = runInNewContext(`({
a: 1,
b: new Date('2022-06-25T01:55:27.743Z'),
c: /test/,
f: Symbol('test'),
})`)
obj1 === obj2 // false
hash(obj1) === hash(obj2, true) // true
```
## Benchmark
```log
┌─────────┬────────────────────────────────┬──────────────────┬───────────────────┬────────────────────────┬────────────────────────┬─────────┐
│ (index) │ Task name │ Latency avg (ns) │ Latency med (ns) │ Throughput avg (ops/s) │ Throughput med (ops/s) │ Samples │
├─────────┼────────────────────────────────┼──────────────────┼───────────────────┼────────────────────────┼────────────────────────┼─────────┤
│ 0 │ 'stable-hash-x' │ '7877.4 ± 1.57%' │ '7042.0 ± 167.00' │ '138708 ± 0.05%' │ '142005 ± 3449' │ 126975 │
│ 1 │ 'hash-object' │ '17632 ± 0.73%' │ '16708 ± 458.00' │ '58820 ± 0.07%' │ '59852 ± 1600' │ 56716 │
│ 2 │ 'json-stringify-deterministic' │ '10901 ± 0.83%' │ '10250 ± 250.00' │ '95860 ± 0.05%' │ '97561 ± 2439' │ 91739 │
│ 3 │ 'stable-hash' │ '8318.5 ± 3.27%' │ '7042.0 ± 208.00' │ '138347 ± 0.06%' │ '142005 ± 4074' │ 120214 │
└─────────┴────────────────────────────────┴──────────────────┴───────────────────┴────────────────────────┴────────────────────────┴─────────┘
```
## Notes
This function does something similar to `JSON.stringify`, but more than it. It doesn't generate a secure checksum, which usually has a fixed length and is hard to be reversed. With `stable-hash-x` it's still possible to get the original data. Also, the output might include any charaters, not just alphabets and numbers like other hash algorithms. So:
- Use another encoding layer on top of it if you want to display the output.
- Use another crypto layer on top of it if you want to have a secure and fixed length hash.
```js
import crypto from 'node:crypto'
import { hash } from 'stable-hash-x'
const weakHash = hash(anyJavaScriptValueHere)
const encodedHash = Buffer.from(weakHash).toString('base64')
const safeHash = crypto.createHash('MD5').update(weakHash).digest('hex')
```
Also, the consistency of this lib is sometimes guaranteed by the singularity of the WeakMap instance. So it might not generate the consistent results when running in different runtimes, e.g. server/client or parent/worker scenarios.
## Sponsors and Backers
[](https://github.com/sponsors/JounQin)
### Sponsors
| 1stG | RxTS | UnRS | UnTS |
| ---------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------- |
| [](https://opencollective.com/1stG) | [](https://opencollective.com/rxts) | [](https://opencollective.com/unrs) | [](https://opencollective.com/unts) |
### Backers
| 1stG | RxTS | UnRS | UnTS |
| ------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- |
| [](https://opencollective.com/1stG) | [](https://opencollective.com/rxts) | [](https://opencollective.com/unrs) | [](https://opencollective.com/unts) |
## Changelog
Detailed changes for each release are documented in [CHANGELOG.md](./CHANGELOG.md).
## License
Originally created by [Shu Ding].
[MIT][] © [JounQin][]@[1stG.me][]
[1stG.me]: https://www.1stG.me
[MIT]: http://opensource.org/licenses/MIT
[JounQin]: https://github.com/JounQin
[Shu Ding]: https://github.com/shuding