https://github.com/ljharb/json-stable-stringify
https://github.com/ljharb/json-stable-stringify
Last synced: 5 months ago
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- Host: GitHub
- URL: https://github.com/ljharb/json-stable-stringify
- Owner: ljharb
- License: mit
- Created: 2022-10-25T08:06:19.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2025-04-22T05:35:23.000Z (6 months ago)
- Last Synced: 2025-05-14T01:13:19.256Z (5 months ago)
- Language: JavaScript
- Homepage:
- Size: 115 KB
- Stars: 63
- Watchers: 2
- Forks: 13
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Funding: .github/FUNDING.yml
- License: LICENSE
Awesome Lists containing this project
README
# json-stable-stringify [![Version Badge][npm-version-svg]][package-url]
[![github actions][actions-image]][actions-url]
[![coverage][codecov-image]][codecov-url]
[![License][license-image]][license-url]
[![Downloads][downloads-image]][downloads-url]
[![npm badge][npm-badge-png]][package-url]
deterministic version of `JSON.stringify()` so you can get a consistent hash from stringified results
You can also pass in a custom comparison function.
# example
``` js
const stringify = require('json-stable-stringify');
const obj = { c: 8, b: [{ z: 6, y: 5, x: 4 }, 7], a: 3 };
console.log(stringify(obj));
```
output:
```
{"a":3,"b":[{"x":4,"y":5,"z":6},7],"c":8}
```
# methods
``` js
const stringify = require('json-stable-stringify')
```
## const str = stringify(obj, opts)
Return a deterministic stringified string `str` from the object `obj`.
## options
### cmp
If `opts` is given, you can supply an `opts.cmp` to have a custom comparison function for object keys.
Your function `opts.cmp` is called with these parameters:
``` js
opts.cmp({ key: akey, value: avalue }, { key: bkey, value: bvalue }, { get(key): value })
```
For example, to sort on the object key names in reverse order you could write:
``` js
const stringify = require('json-stable-stringify');
const obj = { c: 8, b: [{ z: 6, y: 5, x: 4 },7], a: 3 };
const s = stringify(obj, function (a, b) {
return b.key.localeCompare(a.key);
});
console.log(s);
```
which results in the output string:
``` js
{"c":8,"b":[{"z":6,"y":5,"x":4},7],"a":3}
```
Or if you wanted to sort on the object values in reverse order, you could write:
``` js
const stringify = require('json-stable-stringify');
const obj = { d: 6, c: 5, b: [{ z: 3, y: 2, x: 1 }, 9], a: 10 };
const s = stringify(obj, function (a, b) {
return a.value < b.value ? 1 : -1;
});
console.log(s);
```
which outputs:
``` js
{"d":6,"c":5,"b":[{"z":3,"y":2,"x":1},9],"a":10}
```
An additional param `get(key)` returns the value of the key from the object being currently compared.
### space
If you specify `opts.space`, it will indent the output for pretty-printing.
Valid values are strings (e.g. `{space: \t}`) or a number of spaces
(`{space: 3}`).
For example:
```js
const obj = { b: 1, a: { foo: 'bar', and: [1, 2, 3] } };
const s = stringify(obj, { space: ' ' });
console.log(s);
```
which outputs:
```
{
"a": {
"and": [
1,
2,
3
],
"foo": "bar"
},
"b": 1
}
```
### replacer
The replacer parameter is a function `opts.replacer(key, value)` that behaves the same as the replacer
[from the core JSON object](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Using_native_JSON#The_replacer_parameter).
# install
With [npm](https://npmjs.org) do:
```
npm install json-stable-stringify
```
# license
MIT
[package-url]: https://npmjs.org/package/json-stable-stringify
[npm-version-svg]: https://versionbadg.es/ljharb/json-stable-stringify.svg
[deps-svg]: https://david-dm.org/ljharb/json-stable-stringify.svg
[deps-url]: https://david-dm.org/ljharb/json-stable-stringify
[dev-deps-svg]: https://david-dm.org/ljharb/json-stable-stringify/dev-status.svg
[dev-deps-url]: https://david-dm.org/ljharb/json-stable-stringify#info=devDependencies
[npm-badge-png]: https://nodei.co/npm/json-stable-stringify.png?downloads=true&stars=true
[license-image]: https://img.shields.io/npm/l/json-stable-stringify.svg
[license-url]: LICENSE
[downloads-image]: https://img.shields.io/npm/dm/json-stable-stringify.svg
[downloads-url]: https://npm-stat.com/charts.html?package=json-stable-stringify
[codecov-image]: https://codecov.io/gh/ljharb/json-stable-stringify/branch/main/graphs/badge.svg
[codecov-url]: https://app.codecov.io/gh/ljharb/json-stable-stringify/
[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/json-stable-stringify
[actions-url]: https://github.com/ljharb/json-stable-stringify/actions